Method and device for subcutaneous injection with electrical stimulation of nerve

CLAIMING FOR PRIORITY

[001] This application is a continuation of US patent application No. 15 / 062,685, filed March 7, 2016, and US patent application No. 15 / 141,231, filed April 28, 2016. This application also claims priority under provisional patent application US No. 62 / 242,745, filed Oct. 16, 2015. The disclosures of each of the above patent applications are hereby incorporated by reference in their entirety.

FIELD OF TECHNOLOGY

[002] The present invention relates generally to drug delivery improvements and, in particular, to systems for subcutaneous injection / aspiration into a patient's body. More specifically, the present invention provides a method and apparatus for performing an injection that provides a clinician with feedback during subcutaneous needle placement.

LEVEL OF TECHNOLOGY

[003] In various medical procedures, it is desirable to position the needle in a specific area for administering a solution of a drug, such as an anesthetic or analgesic. Regional anesthesia with epidural tissue block and peripheral nerve block (PNB) are two examples. With regard to epidural anesthesia, to achieve effective regional anesthesia and blockade of nerve transmission to the central nervous system, an appropriate volume of local anesthetic solution must be injected in the immediate vicinity of the spinal cord at a specific level of the spinal column within the anatomical region known as the epidural "space". For a peripheral nerve block, a target nerve is identified and a needle is placed in close proximity to deliver an anesthetic to the nerve. Each of these procedures has complications related to the relevant anatomy.

[004] The epidural space is the part of the spinal canal not occupied by the dura mater and its contents. It lies between the dura mater and the periosteum, which covers the inner side of the spinal canal. The epidural space extends from the foramen magnum to the sacral fissure. The sheathed anterior and posterior nerve roots pass through the epidural space and join between the vertebral bodies and intervertebral discs. The epidural space from the lateral side is limited by the periosteum of the pedicles of the vertebral arches and the intervertebral foramen. The posterior epidural space is limited by structures such as the periosteum of the anterior surface of the plates, the articular processes and their connective ligaments, the periosteum of the base of the spinous processes, and the spaces between the plates filled with the yellow ligament. This space contains venous plexuses and adipose tissue, which is continuously associated with adipose tissue in the paravertebral space.

[005] The fluid-filled epidural space (posterior epidural space) is a limited anatomical area of ​​irregular shape with an area of ​​several square millimeters in relation to the cross section of the vertebrae and spine. The specified fluid-filled space is extremely narrow and is located in close proximity to the membrane of the spinal column, with the ligamentum flavum being located in close proximity to it. Thus, during insertion of the epidural needle, it is desirable to know when the tip of the epidural needle enters the fluid-filled space after ligament ligamentumum puncture. If the needle continues to advance after the tip enters the fluid-filled space, the needle can pierce the dura mater.

[006] The attending physician palpates the spinal column at the appropriate level between the vertebrae. Local anesthesia is performed through the superficial tissues, resulting in local anesthesia. The dermis is then punctured using a Tuohy needle and the needle is advanced while the doctor simultaneously presses on the syringe plunger. The pressure exerted on the piston inadvertently causes the volume of fluid to be continuously expelled from the needle into the tissues.

[007] Unfortunately, if the epidural procedure is not performed correctly or if the attention of the physician is distracted during the procedure, the needle can be advanced beyond its intended target space and can damage the spinal cord. It is known that from 2% to 3% of all injections are performed outside the intended target space and penetrate through the dura mater up to direct contact of the needle with the space in which the cerebrospinal fluid is located, and in some cases to direct contact with the spinal cord. which can lead to a life-threatening situation. Thus, the physician's precise and careful visual attention must be maintained throughout the entire procedure to monitor the exact location of the needle as it is inserted into the epidural space.

[008] In addition, when the Tuohy needle is moved after determining the exact location of the epidural space, the needle may be accidentally pulled out of the epidural tissue space when the syringe is removed, or due to accidental movement of the patient or the doctor's hand, or in the worst case, advanced into the dural which results in the so-called "wet touch", which can have dangerous long-term consequences for the patient's health. Even if the initial location of the epidural space has been properly determined, further advancement of the needle while injecting anesthetic solution into the spinal cord can inject a large dose of anesthetic solution into the spinal cord, resulting in temporary or permanent nerve damage.

[009] In addition to the disadvantages described above, pressure monitoring can be complicated by forward movement of the needle through the tissue during penetration. When the needle moves through the tissues in accordance with Newton's third law, pressure is generated that opposes the pressure pressure. The head pressure of the fluid discharged from the tip of the needle is counteracted by the counter-force generated as the needle is advanced through the tissue. This opposing counter force introduces an error in the outlet pressure measurement, in particular if the pressure is monitored on a continuous basis in real time during advancement and injection of the drug into the tissue. Inhomogeneous movement as the needle advances into the tissue mass causes pressure surges, and inaccuracies in pressure measurements can lead to false positives of maximum outlet pressure.

[0010] Below with reference to FIG. 12 describes the histology of the peripheral nervous system. The basic building block of the central and peripheral nervous systems is a single cellular unit, commonly known as an axon. The brain and central nervous system are made up of millions of axons. Branches from the central nervous system of the brainstem and spinal cord are a collection of highly organized axons, through which a network of sensory and motor pathways is formed. Collectively, this network of pathways is known as the peripheral nervous system.

[0011] In the peripheral nervous system, each individual axon is surrounded by a supporting connective tissue called endoneurium. The endoneurium contains small blood vessels (capillaries and venules) that deliver nutrients to these axons. The axons collectively form highly organized, densely packed fibers, which are surrounded by a thin but dense multilayer sheath of connective tissue that surrounds these fibers and forms a membrane structure called perineurium. The perineurium provides a dense protective layer, which is a physical and chemical barrier that provides sufficient protection for axons and endoneurium. This barrier is akin to the blood-brain barrier.

[0012] This separate formation of endoneurium and perineurium is called peripheral nerve fiber. When nerve fibers join together, they form fascicular bundles covered with epineurium, which is a connective tissue sometimes called internal epineurium. Many groups of nerve bundles are located in a heterogeneous matrix of connective tissue (fibrous-adipose tissue), which contains medium-sized vessels that are loosely located with the outer dense connective tissue. The bundle fascicular structures, surrounded by this additional densely and highly organized layer of fibrous tissue, called the external epineurium, are peripheral nerves.

[0013] The outer epineurium, being the outer layer, is in contact with adjacent structures. Loose connective tissue fills the space between the nerve and the surrounding tissue in conjunction with the external epineurium. Thus, there is an additional multilayered border outside the external epineurium that runs along the entire length of the nerve and is composed of extraneural connective tissue known as paraneurium. Laraneurium is a distinguishable multi-layered functional structure that allows the nerve to slide relative to other anatomical structures during musculoskeletal movements.

[0014] In 1912, electrical stimulation was proposed to facilitate the location of a nerve branch. Electrical nerve stimulation was introduced based on the understanding that nerve transmission is an electrochemical excitation response that travels along a nerve (axon). The use of stimulation of the body with an electric current made it possible to reveal the indirect excitation of both sensory fibers and motor fibers of the nerve. It turned out that when using electrical stimulation, there is a visible muscle contraction. When modulating the frequency and intensity of the discharge, contractions and relaxation of muscle groups innervated by the nerve branch were observed. This use of an indirect electrical discharge to elicit a response from a specific nerve has not become widespread, since physicians did not have the ability to precisely control the various parameters of the applied current. Disadvantages known since the first nerve stimulation still exist today and include:

- The inability to accurately modulate an electrical discharge at given distances applied to a surface in the projection of a nerve branch limits the benefits of nerve stimulation in identifying a particular branch of a nerve when nerve stimulation is used as the primary means of locating a nerve branch. For specific distances, when approaching a nerve branch blindly, different discharge rates in the range of 2.0 mA to 0.2 mA are recommended. However, there is no correlation between distance and intensity, as determined by the apparent response in the form of muscle contraction. Thus, more intense stimulation that elicits a visible response does not necessarily mean that the needle is farther away from the intended branch of the nerve. And the visible reaction to a less intense electrical discharge does not mean that the needle is in a position closer to the superficial extraneural and / or is located within the nerve, i.e. reached an intraneural position. Indeed, there does not seem to be a unanimous opinion regarding the location of the needle (intraneural or extraneural), determined on the basis of the response to an electrical discharge, regardless of its intensity, frequency and duration, applied to the nerve at a given distance.

- Another disadvantage of the method of nerve stimulation is the impossibility of setting the appropriate discharge for a certain distance from the outer surface of the nerve bundle, i.e. with extrafascicular position. The situation is further exacerbated if an intense shock of more than 1.0 mA is used in the intrafascicular position, as it can cause a severe reaction in the patient or, worse still, result in irreversible damage due to excessive electrical shock applied directly to the axon. Thus, it is impossible to determine which appropriate discharge should be applied for a particular distance from the nerve bundle.

- Another disadvantage is that confounding factors do not allow nerve stimulation to be considered accurate. These factors relate to the anatomical variation in a given patient as well as the anatomical variation between different patients. The body is made up of various tissue types, which include connective tissue from mineralized and non-mineralized tissues. These tissues are composed of water and collagen, adipose tissue (fat), muscle tissue, fluids (blood), bones, cartilage, etc. Each tissue type has a different electrical resistance and / or charging capacity when the discharge is applied to a target at a given distance. The variability of the fabric should not be underestimated or predicted. Consequently, prior art devices have the disadvantage of being unable to quantify the intensity of a particular discharge for a particular location. This results in the inability to elicit a predictable response to a given electrical discharge when used as the primary means of locating or proximity to a particular nerve.

[0015] In summary, variables such as discharge rate, frequency, and tissue electrical resistance do not allow standardization of the method to be able to locate a particular branch of a nerve.

DISCLOSURE OF THE INVENTION

[0016] In light of the drawbacks of the prior art, the present invention provides an injection system that improves the reliability and safety of injections, particularly injections that are performed to identify fluid filled body cavities in narrow layers of fascia or connective tissue. Based on the information, in particular, the results of continuous monitoring of the pressure projected onto the surface of the patient's body at the needle entry site, the operator can carefully and continuously monitor the movement of the needle while obtaining critical injection parameters such as outlet pressure, flow rate, warnings, threshold changes. outlet pressure values, as well as any important information that is usually shown elsewhere. This approach allows the operator to always concentrate visual attention on the injection site.

[0017] In addition, in accordance with another aspect of the present invention, there is provided an apparatus and method providing a mechanism for an operator to continuously guide needle insertion while receiving visual information projected onto a patient's body surface at an injection site, and thus allowing the operator to continuously hold Needle field of view and injection site for continuous fine motor coordination. This information can be provided in a variety of forms, from color variations, images, numbers, words and visual changes to forms such as intensity, blinking, coordinated lighting patterns, and the like.

[0018] According to another aspect of the present invention, there is provided a drug delivery device that continuously monitors the pressure of a fluid being introduced into a subject's body. The measured pressure resistance can then be continuously converted into a visual signal. The measurement results are then presented to the healthcare professional to determine or confirm whether the drug being administered is delivered to the target tissue. In addition, measurements are also recorded for later review and documentation of the clinical case. The upper pressure thresholds, as well as the control of the rate of administration of the drug, can be predetermined to eliminate the possibility of using excess pressure and / or rate of administration of the drug during this process.

[0019] In accordance with another aspect of the present invention, there is provided a method and apparatus for using the counter pressure in calculating the outlet pressure. The counter pressure depends on the speed of insertion of the needle. Thus, the system contains a mechanism for controlling the speed of needle insertion. In particular, the system may include needle marks as well as auditory or visual cues to suggest an appropriate needle insertion speed.

[0020] According to another aspect of the present invention, there is provided a hand-held unit to which a labeled needle is connected, adapted to accommodate a small display device, such as a light emitting diode or display screen that reproduces a blinking or visual instruction, and / or a loudspeaker delivering beep or beep, which may be intermittent, to coordinate the predetermined forward movement of the needle with the indicated visual or audible signals in relation to the advance of the needle based on the indicated marks on the surface of the needle as it penetrates the skin or other part of the body. Audible and visual modulations determine the speed of the needle advance so that the speed of the needle advance can be coordinated with the forward movement to improve the accuracy of determining the occurring back pressure used in calculations while monitoring the outlet pressure in real time.

[0021] According to one aspect of the present invention, a mechanism is provided for distinguishing between intrafascicular and extrafascicular needle placement.

[0022] According to another aspect of the present invention, a current discharge is transmitted via an ionic solution through a disposable syringe and tubing to the tip of a needle to stimulate a nerve.

[0023] According to another aspect of the present invention, there is provided a system that provides a constant flow of fluid from the tip of the needle during the advancement of the needle through tissues during peripheral nerve blockade to prevent the tip of the needle from being inserted into the nerve bundle. The constant flow of fluid from the tip of the needle acts as a means to displace or repulse dense structures from the tip of the needle as it is advanced.

[0024] According to another aspect of the present invention, there is provided a system that provides a certain speed or rate of movement of the needle forward in tissue to prevent biasing force of counter pressure applied to the needle when it advances the specified needle in and through tissue, while simultaneously and continuously measuring pressure at the tip of the needle.

[0025] According to another aspect of the present invention, when the needle does not advance, the back pressure is not subtracted from the head pressure when calculating the outlet pressure. It should be understood that a button or control on the handpiece may also be activated to correspond to forward movements in which the back pressure is subtracted from the head pressure in calculating the pressure, and thus a means is provided for distinguishing between a state when the needle is advancing and a state when the needle remains stationary within the fabric.

[0026] According to the present invention, there is also provided a hand-held unit, to which a marked needle is connected, and which is designed to accommodate a small light-emitting diode or display screen and / or a loudspeaker, the blinking and / or sound signal of which is coordinated with the indicated advance speed of the specified needle ... In one embodiment, the handheld unit comprises input devices for controlling the rate of administration of the drug, electrical stimulation, and communication with the central processing unit of the execution unit. In addition, in one embodiment, the handpiece includes a vibration chip or element for vibrating the handpiece to transmit a command or signal from a CPU to an operator. This vibration sensation can be discrete and can present a command warning or signal to the operator requiring a response. According to another embodiment, the hand-held unit also includes an output display device for additional display of information.

[0027] According to the present invention, there is also provided a peripheral nerve block injection device that uses a maximum backpressure range of 75 mmHg. (10.0 kPa) up to 500 mm Hg (66.6 kPa) to initiate electrical stimulation. Instantaneous discrete current delivery can be provided when a specific pressure value is detected within a pressure range. This signal is intended to control an instantaneous discrete current supply at a specific pressure value within a set pressure range.

[0028] In yet another aspect of the present invention, the system uses a CPU-set biasing head pressure value that is determined by the speed (tempo) and correlates with the speed (tempo) of forward movement of the marked needle in the tissue. The offset head pressure value is calculated and taken into account when calculating the head pressure value to eliminate pressure shift caused by counter pressure on the needle resulting from forward movement of the needle while using continuous flow and pressure monitoring.

[0029] According to another aspect of the present invention, there is provided an injection device that provides a current of 0.15 mA to 2.0 mA. The current is supplied in response to the determined output pressure. In addition, the electrical discharge must act for a discrete period from 1.0 sec to 10.0 sec. At the same time, when an electrical discharge acts, a control signal is transmitted to the central processor, requiring a response. An example of a response to a control signal:

i) confirmation of muscle contraction;

ii) changing the rate of administration of the drug to a higher one for dosing the drug.

[0030] According to yet another aspect of the present invention, there must be a first state (a specific outlet pressure value at a constant flow rate) and a second state (electric current stimulation) requiring an operator response to set a third state (presence / absence of observation) to obtain a result on exit (instructions and warning signal).

[0031] According to another aspect of the present invention, there is provided a device that provides a means for advancing a needle through tissues at a advancing speed in the range of 2 mm / sec to 20 mm / sec with a constant flow of fluid at a specific drug delivery rate.

[0032] In accordance with another aspect of the present invention, there is provided a method and apparatus for using the counter pressure in calculating the outlet pressure. The counter pressure depends on the speed of insertion of the needle. Thus, the system contains a mechanism for controlling the speed of needle insertion. In particular, the system may include needle marks as well as auditory or visual cues to suggest an appropriate needle insertion speed.

[0033] According to another aspect of the present invention, there is provided a hand-held unit to which a labeled needle is connected and which is configured to receive a small display device, such as a light emitting diode or a display screen, that provides a blinking or visual instruction, and / or a loudspeaker that beeps or beeps, which may be intermittent, to allow coordination of a defined forward movement with said visual or audible signal for advancement of the needle based on markers on the surface of the needle as it penetrates the skin or other body part. Audible and visual modulation determines the rate of advance of the needle so that the rate of advance of the needle can be coordinated with forward movement to improve the accuracy of determining the occurring back pressure, used in calculating the outlet pressure, which is monitored in real time.

BRIEF DESCRIPTION OF DRAWINGS

[0034] The above disclosure and the following detailed description of preferred embodiments of the present invention will be best understood when read with reference to the accompanying drawings, in which:

[0035] FIG. 1 shows a perspective view of a drug delivery system;

[0036] FIG. 2 shows a perspective view of the drug delivery system shown in FIG. 1, without injection unit;

[0037] FIG. 3 shows a side view of an injection assembly for the drug delivery system shown in FIG. 1;

[0038] FIG. 4 shows a fragmentary side view of an alternative injection assembly for the drug delivery system shown in FIG. 1;

[0039] FIG. 5 shows a functional diagram of the drug delivery system shown in FIG. 1;

[0040] FIG. 6 shows a functional block diagram of a drug delivery system in accordance with another embodiment;

[0041] FIG. 7 shows a screen shot of a display monitor for the drug delivery system shown in FIG. 1;

[0042] FIG. 8 shows an enlarged fragmentary sectional view of a portion of the spinal column of a patient with yet another embodiment of a drug delivery system;

[0043] FIG. 9 shows a schematic view of the drug delivery system shown in FIG. 8, when used by a patient;

[0044] FIG. 10 shows a side view of a needle assembly in accordance with another embodiment configured to be coupled to the drug delivery system shown in FIG. 1;

[0045] FIG. 11 shows a graph of fluid pressure versus time for needle insertion in an epidural medication procedure;

[0046] FIG. 12 shows a sectional view of a nerve bundle with nerve fibers;

[0047] FIG. 13 is a side view of an injection device for the drug delivery system shown in FIG. 2; and

[0048] FIG. 14 shows a block diagram of a method for introducing a fluid.

CARRYING OUT THE INVENTION

[0049] In the drawings as a whole and in FIG. 1-3, in particular, a drug infusion system is shown, generally designated by reference number 5. System 5 comprises a disposable injection assembly 10 and a computer-controlled drug delivery instrument 50 referred to as an execution unit. The injection assembly 10 comprises an insertion needle 24 adapted to be inserted into the body of a mammalian subject. The injection unit 10 is connected to an execution unit 50 which, during use, controls the flow of fluid to the injection unit. System 5 also includes one or more output devices that provide data to a healthcare professional during a procedure to assist in the proper insertion of a needle into a subject's body.

[0050] System 5 is configured to determine the precise location of fluid-filled tissue, such as epidural space, intra-articular space, eyeball, cysts, vessels, and other fluid-filled body cavities. The system is also configured to deliver the drug to such fluid-filled tissue. The medicament may contain, but is not limited to, local anesthetic drugs such as corticosteroids, hydroxyapatite, complementary drugs, sclerosing agents, and other drugs that are typically administered into fluid-filled tissue spaces for therapeutic purposes.

[0051] The injected fluid is absorbed into tissues at different rates. As a result, the fluid pressure changes. Thus, this fluid pressure (or internal pressure, referring to tissue resistance pressure) indicates several types of tissue and can be used to identify different tissue types.

[0052] System 5 allows the clinician to accurately identify fluid filled tissue space while limiting drug placement in non-target tissues. This applies to both diagnostic and therapeutic procedures. System 5 uses fluid pressure from the needle or catheter after placement of the needle / catheter in tissue to identify placement accuracy and monitor placement during injection or aspiration.

[0053] In particular, the system 5 includes one or more output devices for providing visual feedback regarding the detected fluid pressure in the insertion needle. The operator uses visual feedback as a guide during insertion needle placement. As shown in FIG. 1 and 2, the first output device may be a video display screen such as an LCD to show data to assist the operator. In addition, a second output device can also be provided. For example, the second output device may be a light emitting element configured to provide an output signal that is within the operator's field of view during a procedure. For example, the second output device may be a light emitting element configured to project a light beam onto the patient's body adjacent to the site where the needle is inserted into the patient's body.

INJECTION UNIT

[0054] As shown in FIG. 3-4, system 5 includes a disposable injection assembly 10 that includes a syringe 18 and an elongated flexible tube 22 having a first end connected to a syringe and an insertion needle 24 connected to a second end. Thus, fluid from the syringe can be displaced through the tube 22 into the needle 24. The injection assembly 10 also includes a pressure sensor for detecting the pressure of the fluid in the injection assembly. The pressure transducer may be located at one of several locations to measure pressure that correlates with the fluid pressure at the tip of the needle 24. In this case, the pressure transducer 20 is an integral fluid pressure transducer attached to the syringe 18 between the syringe and tubing 22. Thus pressure sensor 20 measures the pressure of the fluid as fluid exits the syringe and enters the tube 22 to which the insertion needle 24 is connected.

[0055] A computer controlled drug delivery system 50 in the system shown in FIG. 1-2, provides many patient benefits through precise injection delivery. An output cable 21 connects the pressure sensor 20 to the drug delivery system 50 so that the drug delivery system can vary the flow of fluid from the syringe in response to data from the pressure sensor 20. Thus, the drug delivery system 50 provides accurate and safe administration of drugs for various applications such as epidural anesthesia, intra-articular and other subcutaneous injections. A connection 12 is connected to a second cable 23 and a connector 30 that is inserted into the tool 50. The pressure sensor 20 is connected in series between the front end 19 of the barrel of the syringe 18 and the first end 25 of the tube 22. One exemplary connection is a luer lock for connecting the pressure sensor 20 to the tip of a syringe. The specified connection can be fixed by a threaded connection and / or a non-reversible threaded connection, such as a luer lock. In another embodiment, in this case, the pressure sensor 20 is permanently attached to the syringe by plastic welding or a chemical bonding agent such as an adhesive. Thus, the instantaneous actual fluid pressure in the drug delivery line 22 is recognized and used by the instrument, which provides an accurate approximation of the actual instantaneous fluid pressure at the point of the needle 24 or at the tip of the needle 24 and thus at the location in the patient's body where the tip of the needle is located. The electronic pressure sensor 20 transmits pressure data via electronic data cables 21, 23 which are connected directly to the central unit 50 for collecting pressure measurements.

[0056] The disposable injection assembly 10 is in the form of a disposable disposable kit in which all components are connected, and in this case, the connection is permanent. For example, the components of the injection assembly can be bonded together by welding or glue, epoxy or other adhesive, i. E. the syringe 18 is permanently connected to an electronic pressure sensor installed in the tube 22 or a transducer 20 permanently connected therebetween. This disposable assembly 10 is used and disposed of as a separate unit. It is also connected to the execution unit 50 via a second connector 16, which can be inserted into connector 14 in a key manner to ensure that only authorized disposable assemblies 10 are used and these assemblies are used only once.

[0057] The electronic pressure sensor 20 can be any of a variety of pressure sensors. One exemplary transducer type is a piezoelectric pressure transducer such as those commercially available from Merit Medical Systems, Inc. such as the Meritrans® brand model MER212 pressure transducer.

[0058] In a preferred embodiment, permanent attachment of the needle may be optional so that the clinician can select the preferred needle for a particular purpose. The components are individually assembled or in a preferred embodiment glued (ie, bonded) together and provided in the form of a single disposable kit for which the appropriate disposable components have been selected.

[0059] The preferred implementation is a connected disposable kit. It is contemplated that various configurations may be used in connection with the tool 50. They consist of components of various sizes, i.e. needles, syringe, tubing and pressure transducers. The system may include an identifying connector that uniquely identifies the details of each injection assembly (eg, needle size, tube length, etc.). The inclusion of an identifying connector in the kit allows you to confirm and identify the intended disposable kit. This approach provides verification of the system, which facilitates the use of the appropriate components and / or drugs. It is contemplated that the pre-filled syringe 18 can be provided with an injection assembly 10, or the syringe can be supplied empty so that it can be filled in situ with the required medication, saline, or other fluid. For pre-filled syringes 18, the identification connector 12 contains (in the microchip) information related to the drug contained in the syringe.

[0060] FIG. 4 shows portions of a disposable injection assembly according to yet another embodiment. This embodiment comprises an axially elongated rigid plastic sterile handle 27 attached to the second end of tube 22 and having a connector, such as a luer lock, that is releasably connected to a needle 24 selected for a particular type of injection into a selected anatomical site. The elongated handle 27 according to this embodiment facilitates manual control and precision in needle placement, in particular due to the pivot control. This is particularly useful for intra-articular (IA) injections (ie, inferior alveolar injections), and may also facilitate epidural and other types of injections. The elongated handle 27 is preferably about 15 cm (about 6 inches) in length, or in the preferred range of about 10-20 cm, with tube 22 being about 122 cm (about 48 inches) long.

AUTOMATED SYSTEM OF FLUID DELIVERY

[0061] As described above, the system 5 includes a fluid delivery system 50 for providing a controlled flow of medication to the injection node 10. Preferably, the fluid delivery system is an automated system, and in this case is a computer controlled fluid delivery system called execution unit 50 ...

[0062] As shown in FIG. 1-4, said execution unit is adapted to operate in conjunction with a disposable injection unit 10. The execution unit has a semi-cylindrical syringe receptacle 52 located in the upper surface of the execution unit 50 as shown in FIG. 2. The nest is adapted to receive the syringe 18 of the injection assembly 10. A pair of spring clips cooperate with the syringe to hold the syringe in the nest 52. The transverse groove in the socket is adapted to engage with the finger stop 88 at the end of the syringe barrel. Thus, the stop for the fingers of the syringe barrel interacts with the groove 55 and prevents axial displacement of the syringe barrel relative to the seat 52. The seat 52 further comprises a portion adapted to receive the plunger 70 of the syringe 18. As shown in FIG. 1, said seat is of such a length that a syringe barrel and piston can be received in the seat when the piston is extended toward the rear end of the piston barrel. In particular, the length of the seat is greater than the maximum length of the syringe in its extended state, so that the syringe can be positioned in the seat without interacting with the plunger when the plunger is extended from the barrel to its maximum length.

[0063] Execution unit 50 includes a movable platform 58 having three spring-loaded thumb rest latches or hooks 60 that are pivotally mounted on platform 58. Execution unit 50 controls displacement of the movable platform to control the release of the fluid from a syringe. In particular, platform 58 is movable along the axis of seat 52 to slide piston 70 into a syringe barrel. Initially, platform 58 is moved forward to engage the piston. In particular, the platform moves forward (to the right of the perspective view shown in FIG. 1) until the beveled surfaces of the three hooks engage with the thumb rest 72 of the piston 70. The continuous displacement of the platform 58 forces the thumb rest to wedge the hooks 60 radially outward until the hooks extend radially outward beyond the outside diameter of said thumb rest. As the platform 58 continues to advance, the beveled surfaces of the hooks 60 pass past the thumb rest 72, and at this point the hooks snap close to each other behind the thumb rest 72, so that the platform reliably interacts with the thumb rest, and the platform is displaced leads to displacement of the piston.

[0064] After platform 58 has gripped the thumb rest, a sensor in execution unit 50 senses resistance to further movement of platform 58 and the platform stops. At this point, the piston 70 is effectively attached axially to the platform 58 due to the engagement of the latches 60 with the thumb rest 72. Thus, further movement from left to right of platform 58 also causes piston 70 to move to the right to displace fluid from the syringe body. Likewise, any retraction of the platform (ie, movement to the left of FIG. 1) causes fluid to be sucked back into the syringe body.

[0065] The pressure sensor 20 of the assembly 10 is inserted into a proprietary connector 12, and the connector 12 is connected to the block 50 via a connector 30. The execution unit 50 houses a microprocessor or central processor 82, a panel 92 with electronic circuits, a power supply 94, and an electronic motor or motors 96 (since two syringes can be used as shown in FIGS. 5-6). Each electronic motor 96 drives a worm shaft 98 which moves the syringe arm 90 forward or backward. The syringe body 90 contains a load cell for detecting force. The armature 90 is connected to the platform 58 so that the platform can be moved in any direction. As indicated above, the disposable injection assembly 10 includes an identification and connection component 12, a syringe 18, a flow pressure sensor 20, a tubing set 22, and a needle 24.

[0066] The execution unit 50 is configured to provide a constant or variable flow of fluid. In this case, the execution unit can provide an intermittent flow of fluid in response to signals received from the electronic pressure transducer 20, which continuously senses the pressure of the fluid during the injection / injection procedure. Based on the predetermined pressure, the execution unit 50 can stop the flow of fluid when the determined pressure exceeds a predetermined threshold value. The predetermined threshold value can be set by the attending physician and stored in the memory 80 of the microprocessor or computer 82 located in the electronic part in the execution unit 50. Likewise, based on the target pressure, fluid flow is resumed when the fluid pressure falls below the target pressure. The same predetermined pressure can be used to control the interruption and resumption of fluid flow. In this case, the pressure will build up while the fluid initially enters the tissue, to a predetermined level, and then the flow will stop until the pressure drops below that predetermined level. When the pressure of the fluid falls below a predetermined level, the flow of the fluid will resume. Thus, the flow of fluid can start and stop during the procedure, turning into an intermittent flow of fluid.

[0067] The system can include predetermined pressure thresholds used to control the flow of medication from syringe 18 during a procedure. This allows the attending physician to selectively administer drugs to specific locations and targeted tissues for diagnostic and therapeutic procedures. The preselected maximum pressure limits and / or flow rates are stored in memory 80 and determine the maximum recommended pressures that patients are typically subjected to, or other criteria. When the pressure approaches this threshold, optical and / or audible alarms are generated for the attending physician, i.e. on the screen 62 and through the speaker 84, which are activated by data from the microprocessor 82. In addition, data describing the entire injection process is stored in memory 80 for later analysis.

[0068] The system 5 may directly measure the pressure of the fluid in the injection assembly 10, or the system may measure a characteristic indicative of the pressure of the fluid in the injection assembly. For example, pressure can be measured by determining the pressure resistance measured during infusion. The measured pressure resistance is continuously converted into a visual signal during the insertion procedure. However, drug consumption during the procedure can be based on fluid pressure detected in real time during the procedure. Thus, the flow rate of the drug varies and depends on the pressure in the system. Thus, the pressure of the fluid can be the primary control variable of the system.

[0069] Thus, the rate of drug delivery becomes a secondary variable that is modulated within a predetermined range to maintain the desired fluid flow. In one particular embodiment, the flow of fluid is stopped when the pressure exceeds a predetermined threshold (maximum pressure). The rate of delivery of the drug as a secondary variable may be limited so that the fluid is not injected too quickly at low pressure. It is assumed that the relationship between pressure and flow rate of a fluid can be binary or continuous. Binary communication exists when the injection device is configured to deliver fluid at a single predetermined rate for any pressure that is less than a predetermined maximum value. Thus, the flow of fluid is resumed or stopped based on whether the pressure exceeds a specified threshold. In another embodiment, the flow rate can also be modulated as a function of pressure. In this case, the flow rate will decrease as the pressure approaches the maximum allowable value and increase as the pressure drops. In another embodiment, the flow rate can be limited to a first predetermined maximum pressure and can be resumed at a second predetermined pressure that is different from the first.

[0070] As noted above, the system 5 may include a mechanism for displaying appropriate injection data, including, for example, instantaneous flow rates, pressures, and injection volumes on the screen 62 of the execution unit 50. Similarly, the system may include a mechanism for recording such information for later analysis after the procedure. For example, the system may include a nonvolatile electronic storage device such as a hard disk drive, flash drive, optical drive, or other medium for storing electronic data.

[0071] All measurements and information can be presented to the attending physician "in real time" so that the attending physician can determine if the injection is being delivered to the intended location and / or correctly defined tissues and modify the injection process accordingly. In addition, measurements can be recorded for later review and documentation of the clinical case.

[0072] It is also contemplated that a plurality of syringes that are driven by separate plungers to enable multiple drug delivery can be used, as well as a second syringe actuator that does not require a predetermined pressure to be achieved for any of the above purpose. The second actuator can be programmed for a specific rate of drug delivery to allow the infusion of a drug, such as a local anesthetic and other therapeutic drugs, into various tissues.

[0073] In yet another embodiment, the device may comprise two distinct syringe actuators, both of which are modulated based on fluid pressure, as described hereinabove.

VISUAL FLUID PRESSURE INDICATOR

[0074] As shown in FIG. 1, the system includes a visual signal generator 100 for providing visual signals corresponding to the fluid pressures detected by the system. The visual signal generator 100 provides feedback to the operator to guide the operator as the needle 24 is inserted into the subject's body. In particular, visual signals from the visual signal generator 100 provide continuous signals related to the proximity of the needle tip to a target location, such as a fluid filled space.

[0075] The visual signal generator 100 can be any of various indicator lights. For example, as shown in FIG. 1, the visual signal generator may include a light head 105 mounted at the end of flexible cable 102. Flexible cable 102 may be sufficiently stiff so that the cable can be bent into a desired position to achieve the desired orientation and maintain this position without external support. Thus, the operator can position the illumination element so that the light head 105 is directed towards a surface that is in the operator's field of view, while the operator's attention is focused on the insertion site on the patient's body. For example, light from a lighting element can be projected onto a surface adjacent to the subject's body, such as a wall or other flat surface. In another embodiment, preferably, the light head 105 can be positioned to project the light beam onto the patient. For example, light from a lighting element can be directed directly onto a subject's skin or clothing. More specifically, light can be projected onto the patient's body near the insertion site so that the light signals from the visual signal generator 100 are within the operator's field of view while the operator visually tracks the insertion site. Thus, the visual signals from the visual signal generator 100 provide the operator with useful information regarding the injection without having to look away from the injection site.

[0076] The light head 105 may include any of a variety of lighting elements. For example, light head 105 may include a light emitting diode, incandescent lamp, laser diode, or any other light emitting element. In addition, the lighting element 105 may include a plurality of such light emitting elements. Also, the lighting element 105 may comprise a plurality of lighting elements that change light intensity, color, and / or coherence. While light head 105 may contain one or more scattered light elements, preferably light head 105 provides a light beam that is coherent enough to be projected onto a patient and easily discernible by an operator during a procedure. Therefore, the light head 105 may include a lens 107 for focusing light of the lighting element (s) as shown in FIG. 2.

[0077] The light generated by the visual signal generator 100 is controlled by the execution unit 50. In particular, the visual signal generator 100 is controlled in response to electrical signals from the microprocessor 80 of the execution unit 50. The execution unit may comprise a separate control circuit that controls the visual signal generator 100 in response to control signals received from the execution unit microprocessor 80. In particular, the electronic control device for the lighting circuit can be configured to separately control each of the plurality of lighting elements in the light head 105. The light control circuit can control each lighting element by turning it on or off. The light control circuit can control the intensity of each lighting element. In addition, the light control circuit can control combinations of lighting elements to change the light produced by the visual generator. For example, the light control circuitry may employ combinations of lighting elements to change the color of the luminous flux emitted by the light head 105. For example, the light head can include a plurality of red, green, and blue lighting elements, and the electronic light control device can selectively control the illumination of the multi-colored lighting elements to create a beam of light having red, yellow, or green, or any of different colors.

[0078] In another embodiment, the light control circuit can control the lighting elements to create varying patterns of light projected by the visual signal generator. For example, a visual signal generator can project a beam of light having a specific pattern. In one embodiment, the visual signal generator 100 projects a first colored signal when the pressure sensor 20 detects a pressure within the first range; and the visual signal generator can project a second colored signal when the pressure sensor detects a pressure within the second range. In addition, when the pressure sensor detects a signal approaching a threshold value between the first range and the second pressure range, the visual signal generator can project a beam in which one discernible portion of the beam has a first color and another distinguishable portion of the beam has a second color.

[0079] In addition to controlling light intensity, color, and pattern, the light control circuit can control the flashing rate of the light. In particular, the light can be intermittent so that the light beam flashes on and off. The frequency of the on / off cycle can be controlled in response to pressure sensed by the system. The light control circuit can control the visual signal generator based on the absolute value of the detected pressure. In another embodiment, the light driving circuit can control the indicator based on a relative pressure detected value, meaning a current value relative to the most recently detected pressure. Thus, the light control circuit can change the light depending on whether the pressure is increased or decreased. Likewise, the light control circuit can control the light based on both the absolute and the relative value of the detected pressure. For example, the light control circuitry can control the lighting elements to generate a light beam having a specific color based on the detected pressure being within a specific pressure range. In addition, based on the relative pressure indicating that the pressure is rising, the light control circuit may cause the visual signal generator to flash in a selected color. In addition, the light can be controlled so that the blinking frequency increases as the pressure increases to the upper end of the pressure range. As soon as the pressure increases beyond the pressure range, so that the pressure is already at the lower end of the second pressure range, the light control circuit can control the visual signal generator so that it generates different colors of light flashing at a low frequency when the pressure is in the lower end of the second pressure range.

[0080] From the above, it will be appreciated that the visual signal generator 100 can provide a wide variety of colors and patterns that can provide continuous feedback to the operator for use in guidance during a needle insertion procedure. Some examples of a specific method are described below in which the visual signal generator 100 can provide continuous feedback light signals.

[0081] As described above, the visual signal generator can project a light beam onto any of a variety of surfaces, allowing the operator to see the light signal while maintaining focus on the injection site. The following describes how the light is projected onto the patient's body. It should be understood that this description is only given as an example of a surface onto which light is projected.

[0082] The execution unit 50 may be programmed so that the visual signal generator projects yellow light when the sensed pressure is in the 0-20 mmHg range. (0-2.7 kPa), green light when the detected pressure is in the range of 20-40 mm Hg. (2.7-5.3 kPa), and red light when the detected pressure is in the range of 40-200 mm Hg. (5.3-26.7 KPa). The light may flicker when the pressure increases. Thus, the visual signal generator projects a flashing yellow beam onto the patient when the needle is inserted into the patient's body and the pressure increases to a threshold pressure of 20 mmHg. (2.7 KPa). As soon as the pressure increases to 20 mm Hg. (2.7 kPa), the indicator light changes so that a green light beam is projected onto the patient. And the light flashes as the pressure increases. If the pressure remains constant, the light also remains constant (i.e. no blinking). In addition, when advancing the needle and increasing the pressure to 40 mm Hg. (5.3 kPa) the blinking frequency increases until the pressure reaches 40 mmHg. (5.3 KPa). At this point, the flashing frequency is significantly reduced and the color of the light beam changes to red.

[0083] In the above description, the visual signal generator provides a continuous feedback signal corresponding to the detected pressure, so that the operator can easily recognize various information about the detected pressure, including, in addition to pressure, the rate of change of pressure and the direction of change of pressure (increase, decrease) or slight change ... It should also be understood that the visual signal generator may provide color signals that indicate a warning, alarm, system error or failure, or any other miscellaneous system malfunction that requires operator attention. For example, in the above example, red is used to indicate that the fluid pressure is within a specific range. In another embodiment, red (or any other color) may be for indicating a warning, error, or other alarm. Thus, when the visual signal generator 100 projects a red beam or blinks a red beam, the operator is easily alerted to a problem that requires attention.

[0084] In addition, in the above description, the visual signal generator 100 provides a beam that corresponds to a specific state or characteristic of the pressure at the outlet of the injection unit. It should also be understood that the absence of light from the visual signal generator can also be used to provide information to the operator. For example, the visual signal generator can be turned off to prevent light from being projected when the pressure drops within a certain range. For example, if the pressure is below 10 mm Hg. (1.3 kPa), the visual signal generator can be switched off.

[0085] In addition to various colors and patterns, the visual signal generator 100 can provide graphical and / or human-readable information, including but not limited to numbers, letters, and symbols. For example, the visual signal generator 100 may project a numerical value of the pressure detected by the pressure sensor 20. Thus, the operator can easily see the pressure change in real time, without distracting his attention from the injection site and the needle that he is manipulating. In addition, graphic information can be combined with color or pattern changes to provide additional information to the operator. For example, a visual signal generator can project a numerical value of the pressure detected in real time. In addition, the color of the projected digits can change when the pressure value changes from one pressure range to the next, as described above. Likewise, the amount can be projected with a constant color such as a dark color, and the amounts can be embedded in a background having a color that belongs to a specific pressure range or other characteristic, as described above.

[0086] Of course, the graphical information projected by the visual signal generator is not limited to alphanumeric characters. The visual signal generator can provide any different types of graphic data. For example, a visual signal generator can project a graph of detected pressure values ​​over a long period of time so that an operator can see a graphical illustration of the pressure change on the graph, including the amount of change, rate of change, and various inflection points. Likewise, the displayed data should not be limited to real-time pressure values ​​detected by the pressure sensor 20 or otherwise obtained. The data projected by the visual signal generator may include information such as the rate at which the drug or fluid is delivered through the injection assembly 10, the amount of fluid in the syringe, the elapsed time since the start of needle insertion, and patient data. Accordingly, it should be understood that the visual signal generator may be configured and controlled to project any visual data that may be presented on a display screen, such as an LED screen, an LCD screen, or a CRT screen. The visual signal generator will project such visual data in a manner whereby the operator can easily see the data without taking special steps to obtain it or distracting his attention from the manipulation of the needle.

[0087] In the above description, the visual signal generator 100 is a lighting element that projects visual feedback to an operator for use in guiding needle insertion into a subject's body. In the above embodiments, the visual signal generator 100 is mounted on a semi-rigid arm or cable connected to the execution unit so that the lighting element can be positioned and oriented to project light onto the desired target area. FIG. 4 shows a visual signal generator 200 in accordance with another embodiment. According to this embodiment, the visual signal generator is mounted on an element of the disposable injection assembly 10 and / or is connected directly to said element. In particular, the injection assembly 10 includes an elongated sleeve 27 connected to the fluid tube 22. The sleeve 27 contains a locating element for connecting the needle 24 to the sleeve. For example, the sleeve 27 may include a luer lock.

[0088] As shown in FIG. 4, the visual signal generator 200 may be mounted on the elongated sleeve or otherwise coupled to the elongated sleeve. Thus, the sleeve 27 is an elongated rigid member for supporting the visual generator 200. The visual signal generator projects a visual signal in a forward direction, for example, onto the patient's body or near the injection site. Thus, the visual signal generator can project a beam whose axis is parallel or substantially parallel to the axis of the needle 24. The visual signal generator comprises an elongated cable 206 so that the visual signal generator can extend far from the execution unit 50. In particular, cable 206 includes a connector for connecting a visual signal generator to an execution unit to receive control signals from the execution unit, as described above with reference to the above embodiment.

[0089] Mounted on sleeve 27, visual signal generator 200 is positioned to project a beam of light onto the injection site. In particular, the visual signal generator is mounted such that at least a portion of the light beam 202 emitted by the visual signal generator is parallel to the axis of the insertion needle 24. In particular, the visual signal generator may be connected to the needle such that a substantial portion of the light beam 202 parallel to the axis of the needle.

[0090] In yet another embodiment, the visual indicator is a lighting element, such as one or more fiber optic elements that provide a visual light signal around elongated tube 22 or through elongated tube 22 of injection assembly 10. Thus, light can be projected into the fluid in the tube such that the light signal is near the needle due to the needle being connected to the tube, and the light is projected onto the needle or patient due to the fiber optic elements passing along the tube 22. Accordingly, it should be understood that the visual signal generator can be of any design that provides a visual signal projected onto a surface easily visible to the operator, without distracting the operator from the injection site.

[0091] Thus, the advantages of the present device over the prior art include:

(i) a mechanism for projecting an image representing the pressure value at the outlet to the surface of the patient's body so that the moment of identification of the fluid-filled tissue space, such as the epidural space, intra-articular space, the eyeball, cysts and blood vessels or other vessels of the body, can be determined with a fluid in addition to the above structures;

(ii) a mechanism designed to allow the operator to continuously hold the field of view at the needle insertion site on the patient's body while simultaneously projecting information onto the needle insertion site and eliminating the need for a remote visual screen or the need to look at the screen to obtain said visual information;

(iii) a mechanism configured to monitor the outlet pressure in a series of predetermined ranges, in which the light emitting source allows the operator to objectively discriminate threshold values ​​between different ranges through a discernible visible change such as a color change; and

(iv) a mechanism configured to monitor the outlet pressure through a projected visual image configured to use flashing patterns and / or flashing patterns to report an upward or downward trend in the outlet pressure. This also includes the ability to report a slight change in pressure by providing a visual indication.

CALCULATION OF THE FLUID PRESSURE AT THE NEEDLE OUTPUT

[0092] As described above, the fluid pressure is used to control the operation of the system 5. For example, the visual feedback provided by the visual signal generator 100 is based on the determined fluid pressure. There are various methods for calculating the fluid pressure at the exit of the needle.

[0093] The pressure sensor can detect the pressure of the fluid in the injection assembly 10. For example, as described above, the pressure sensor can be an in-line pressure sensor, such as a pressure sensor commercially available from Merit Medical part # 0001. In another embodiment a pressure sensor built into the execution unit 50 can detect the pressure of the fluid between the syringe 18 and the set 22 of tubing. In another embodiment, a strain gauge located at the abutment of the thumb syringe is used to determine the force acting on the plunger to calculate the pressure in the syringe. The command signal from the pressure sensor transmits pressure data to the central processor for calculation to determine the outlet pressure. The outlet pressure is calculated in accordance with a mathematical formula that subtracts the head pressure in each of the components proximal to the pressure measurement point. In addition, the calculated value is provided in relation to the counter pressure (acting against the head pressure), which correlates with the specific rate (ie, speed) of the forward movement of the needle through physiological tissues. Thus, the pressure value is an input parameter, and the calculated pressure value is calculated taking into account all the assumed system resistances to calculate the final objective value of the outlet pressure. The central processor of the execution unit uses the input values ​​and the setpoints specified in the software for calculation. The final calculated outlet pressure is used to control the central processor and motor, which controls the flow of fluid from the syringe 18.

[0094] As noted above, the back pressure can be subtracted from the measured pressure to determine the final value of the fluid pressure. The back pressure changes in response to the injection rate and the back pressure is subtracted from the measured fluid pressure when calculating the outlet pressure of the fluid. For example, the following values ​​represent back pressure values ​​for various needle insertion speeds.

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[0095] Since the speed of needle insertion significantly affects the counter pressure, it is desirable to control the speed of insertion of the needle. Accordingly, the system can include a manual unit 300 for assisting a user in inserting a needle at a controlled and known rate. In this case, a reusable manual block is used. However, it should be understood that the handpiece means can be used with a disposable needle assembly.

[0096] As shown in FIG. 10, handpiece 300 includes a hollow body 310 and an elongated hollow needle 340 extending forward from the body. A connector 332 is provided to connect the handpiece to the fluid line 22 of the injection assembly 10. In particular, connector 332 provides a moisture-tight seal for connecting the handpiece 300 at the rear end of the housing to facilitate connection of the handpiece to fluid in the syringe. Fluid flows into the handpiece and out through the 340 needle.

[0097] The needle 340 includes a plurality of marks 344 located along the needle body. In particular, the marks contain many lines drawn across the axis of the needle. Marks 344 are located at a certain known distance from each other. In particular, each mark 344 is located at the same distance from an adjacent mark. The marks are preferably located at least along a substantial portion of the length of the needle. In this case, the marks extend from the tip 342 of the needle 340 to the junction between the body 310 and the needle. The increment marks can be laser etched onto the surface of the needle, alternating colors or engravings on the surfaces of the needle at a specific distance, such as in increments of 1.0 cm.

[0098] Hand unit 300 may also include an indicator light 215 configured to provide an operator with regular prompts. Indicator light 315 can be a light emitting diode or other illuminating element that glows at a predetermined frequency depending on the intended injection rate. In particular, before starting the procedure, the operator enters various data regarding the procedure, and based on these data entered by the operator, the speed of needle insertion for the procedure is determined. The speed at which the needle is inserted is used to determine the flashing frequency of indicator 315. As described in detail below, the indicator light works like a metronome, which is a constant pacemaker for tracking needle insertion speed to improve accuracy and stability of needle insertion speed.

[0099] The handheld unit further comprises an audible indicator 320, such as a piezoelectric audible indicator, for emitting an audible signal such as a hum, tone, or ringing. The audible indicator 320 works like the indicator light 315, emitting a regular tone that can be used to set the rhythm for the insertion rate of the needle 24.

[00100] In addition, a control button 325 may be present in the hand-held unit. The control button 325 can act as an on / off button. However, the control button can also be configured to input various control commands. For example, the control button 325 may be configured to cancel one or more operations of the execution unit 50, as described in detail below.

[00101] Finally, the hand-held unit 300 may also include an output device such as a display screen for displaying various information such as the frequency of indicator light 315 and / or audible indicator 320. In addition, the display device can show additional information such as real-time pressure values ​​or "Continue", "Change position", "Enter", Injection rate 1, Injection rate 2, Low speed, High speed, Aspiration alerts. ...

[00102] As described above, the handset includes visual and audible indicators 315, 320. Of course, the handheld does not need to include both audible and visual indicators; it can only contain one indicator. In addition, although visual and audible indicators have been described above, various other alternative indicators may be used instead, such as a vibrating element that provides regular vibration indicator signals.

[00103] The determined audible / visual modulation indicates to the operator to advance the needle a certain increment based on the marks 344 on the needle. The forward displacement by a particular increment is counted after the surface of the needle penetrates the surface of the skin, dermis, or body part into which the needle penetrates. The speed from 0.5 cm / sec to 2.0 cm / sec is represented as the range of movement of the needle. Accurate movement speed is achieved by coordinating audio or visual modulation with the movement of a marked needle that penetrates the surface, this movement is noticeable by visual marks on the surface of the needle indicating specific distances. The marked needle is then advanced one increment (one notch) through the tissue surface in accordance with one "beep" and / or "blink".

[00104] The speed of the audio and / or visual prompts is set in the CPU and activated by the fluid flow. A range of 0.5 cm / sec to 2.0 cm / sec is contemplated, however, it is understood that any speed of coordinated progressive movement of the marks representing needle movement can be used. This forward travel speed, selected from the target values, introduces the corresponding back pressure value, which will be subtracted from the calculation to determine the objective tissue pressure value.

[00105] As an example of a working speed, the operator advances the needle 1.0 cm with each beep and visual "blinking" of the light emitting diode in order to coordinate the precise speed of the needle advance. This approach provides the ability to maintain accurate needle advancement speed. In addition, during the advancement of the needle, a continuous flow of fluid from the needle is provided, and the pressure is continuously monitored in real time.

[00106] As indicated above, the handpiece 300 may include a control button. The control button can be used when the needle is not advancing. In this case, pressing the button causes a control signal to be sent to the execution unit 50 so that the back pressure value is not subtracted from the output pressure calculation (since the needle does not advance, there is zero or substantially zero back pressure). It is contemplated that a button or control on the handpiece 300 can also be activated to correspond to forward movements in which the back pressure is subtracted from the head pressure calculation, and thus provides a means of distinguishing when the needle is advanced and when it remains stationary. in the fabric. Thus, activation of the button 325 during periods of minimum to zero needle insertion rate contributes to the accuracy of the needle exit pressures into the tissue during the procedure. In addition to the switch or control button described above, the handpiece may contain a second button or control element that, when used in reverse movements, would add additional head pressure to compensate for the back movement that causes the outlet pressure to decrease as the needle moves backward through fabrics.

[00107] In the above description, the handset includes a visual or audible indicator 215, 220 for setting the rhythm of the needle insertion speed. Despite the indicator (s) that can be installed on the handpiece, the above-described visual signal generator 100 can be used to provide visual signals to set the rhythm of the needle insertion rate. In particular, the visual signal generator 100 can project a visual signal at a constant and specific speed or frequency, similar to the flashing of indicator light 315. Since the visual signal generator 100 projects light near the injection site or in the field of view of the injection site, the operator can see the signal of the indicator light for setting the rhythm of needle insertion. Thus, as indicated above, the needle can be used separately from the rest of the handset. In particular, the needle with markers for controlling the speed of its insertion can be used with a conventional injection unit, such as the injection unit 10 described above. In this embodiment, the visual signal generator provides visual cues for controlling needle insertion speed.

[00108] Since the skin color of different people may differ from patient to patient, it is desirable to use an element that provides a uniform indication of signals when they are projected onto the patient's body. For example, it may be desirable to attach a background element onto which a visual signal can be projected. An exemplary background member can be a flexible patch that can be applied directly to the skin of a patient adjacent to the intended site of administration. The patch can be made from any of a variety of flexible materials such as cloth, paper, or plastic.

[00109] The patch has a working side on which visual signals are to be projected and a back side adapted to be attached to a patient. Preferably, the reverse side comprises an adhesive backing so that the patch can be easily adhered directly to the skin of the patient. For the adhesive backing, any of a variety of known adhesives can be used for removable bonding to a patient's body. The working side of the patch can be made in any of various patterns, but preferably the working side is a solid color. In addition, preferably the color of the patch is selected to enhance the contrast between the projected visual signal and the patch. For example, if the projected visual signals are generally dark in color, the patch may have a slightly tinted hue, such as white or off-white. Conversely, if the projected signals are generally light colors, the patch may have a dark tint, such as black.

[00110] As described above, the adhesive backing of the patch can be pressed against the body of the patient to adhere the patch to the patient. Preferably, the patch is applied adjacent to the intended site of administration, such as on the back of the patient near the spine. The visual signal generator is directed to the patch, and then the visual signal generator projects the visual signals as described above.

METHOD FOR INJECTING INJECTION INTO A FLUID-FILLED SPACE IN A PATIENT'S BODY

[00111] The following describes an exemplary method of administering an epidural injection to a patient using the system described above. Of course, the proposed system is not limited to use for administration of epidural injections only. Accordingly, it should be understood that the principles and methods described below can be readily adapted for injection into tissues and anatomical regions other than the epidural space.

[00112] The connective tissues of the body can create pressures above 200 mm Hg. (26.7 kPa) when a fluid is introduced into them at a rate of 0.07 ml / sec. Each tissue has its own characteristics of pressure density, represented as measurable pressures that can be detected in a given tissue type. Tissue density or resistance is measured using fluid pressure input from a computer-controlled drug delivery system configured to detect pressure resistance during infusion. It has also been found that fluid-filled cavities such as epidural tissues, intra-articular spaces, or body vessels have pressures measured at the time of injection that are well below 200 mmHg. (26.7 KPa). In fact, fluid filled cavities have been found to have significantly reduced pressure resistance to fluid flow and typically have pressure resistances close to zero when introduced into these fluid filled tissue regions.

[00113] The first predetermined upper pressure limit is determined by the attending physician. Typically, the first predetermined upper pressure limit is not more than 200 mmHg. (26.7 KPa). Using these settings, injection system 50 injects a small amount of drug into the patient's connective tissues and then selects a second target pressure below 50 mmHg. (6.7 kPa), at which the flow of the fluid is resumed. Therefore, the needle is properly positioned within the fluid-filled epidural tissue space, since the pressure in the epidural tissue space is expected to be from about +15 mmHg to about +15 mmHg. (+2 KPa) up to -15 mm Hg. (-2 kPa), while the pressure inherent in the ligamentum flavum (Ligamentum Flavum) is above 200 mm Hg. (26.7 KPa).

[00114] Measured pressures outside the ligamentous tissues are typically about 100-200 mm Hg. (13.3-26.6 KPa). Using an injection device 50 having a second predetermined pressure at which fluid flow is resumed, i. E. 50 mm Hg (6.7 kPa) or below, there is no significant fluid flow when the needle enters the subcutaneous tissue because the pressure builds up rapidly and persists while the needle is in the subcutaneous tissue (extra-ligamentous tissue). The attending physician, when inserting the Tuohy needle, encounters a yellow ligament. In this case, no fluid flow occurs, since, as indicated above, the yellow ligament exerts a pressure of more than 100 mm Hg. (13.3 KPa). After penetration through the entire thickness of the ligamentum flavum (i.e., when the needle enters the fluid-filled epidural space), the pressure drops sharply to below 50 mm Hg. (6.7 kPa), as a result of which an additional visual display device is triggered and / or an audible tone is generated and / or a voice message such as "Epidural space detected" sounds. At this point, the drug-containing fluid will begin to flow into the intended target site. Thus, intermittent fluid flow is used to identify target tissues. It is possible that the first and second set pressure values ​​are set the same to allow the fluid flow to resume only after the pressure falls below the set value.

[00115] The pressure sensor 20 or a plurality of sensors of the injection device 50 provide an automatic safety function in the event of an injection needle exiting the epidural tissue space (eg, due to a physician error or patient movement), or when a patient's vessel is threatened. If the needle 24 exits the epidural tissue space when it is withdrawn through the ligamentum flavum or in contact with the dura mater, the pressure will immediately rise to the first selected value of P1, which leads to a slowdown and possible stop of fluid flow at fluid pressures of more than 200 mm Hg. ... (26.7 KPa). This process was found to take about 2 seconds (see Ghelber-Regional Anesthesia and Pain Medicine, Volume 33, No. 4, 2008, p. 349, FIG. 2). If necessary, this pressure change from &lt;50 mm Hg. (&lt;6.7 kPa) up to&gt; 200 mm Hg (&gt; 26.7 kPa) re-triggers the optical and / or acoustic signal to alert the attending physician to misplaced needle. Flow is automatically resumed again when the needle returns to the epidural tissue space and the instantaneous pressure at the needle tip drops below P1, or, in another embodiment, after the pressure is reduced to a second selected pressure P2, which is equal to or below 50 mmHg. (6.7 KPa). This automatic protective function of the injection device helps to prevent the injection of anesthetic solution into the spinal cord.

[00116] FIG. 8 shows a portion of a subject's spinal column for epidural injection. Starting from the outer injection site for the tip of the needle 24 on the left in FIG. 8, the tissues at this site include various layers of skin, adipose and connective tissue 110, behind which is located the epidural space 112, which is an anatomical space of interest in accordance with one embodiment of the present invention. Behind the epidural space 112 is the dura 114 of the spinal cord 116. The rightward tip of the needle 24 passes through the tissues but stops before reaching the spinal cord. In this section, the bones of the spinal column are also shown in section.

[00117] Here, microprocessor 82 and memory 80 are programmed to use a first pressure P1 of, for example, about 200 mmHg. (26.7 kPa), which is equal to or greater than the instantaneous pressure of the fluid at the tip of the needle as it penetrates and moves through the tissue 110. At a pressure of P1 or higher, the motor 96 is stopped and the flow of fluid to the tip of the needle stops. When the tip of the needle enters the epidural space 112, the instantaneous fluid pressure falls below the P1 value and the microprocessor restarts the motor to resume fluid flow, now into the epidural space 112, in one embodiment. In a second embodiment, to resume fluid flow, the second selected pressure P2, stored in memory 80, needs to be reached. According to a third embodiment, upon reaching the third selected pressure P3 stored in the memory 80, which is greater than P2 but less than P1, the flow of fluid stops again. The achievement of this third pressure P3 indicates that the tip of the needle has rested against the dura mater 114 or otherwise left the target anatomical space. The cavities or layers through which the tip of the needle travels correlate with the pressure settings P1, P2 and P3, as shown in FIG. 8.

[00118] The first selected pressure P1 at which the fluid flow is stopped is preferably about 200 mm Hg. (26.7 kPa) for epidural injection, but can range from about 25 mm Hg. (3.3 kPa) to about 300 mm Hg. (40.0 kPa) depending on the tissue that the needle tip pierces first. The pressure P2 at which the fluid flow is resumed is preferably about 50 mmHg. (6.7 kPa) for an epidural injection, but can range from about 20 mmHg. (2.7 kPa) to about 150 mm Hg. (20.0 kPa) depending on the anatomical space of interest. The third selected pressure P3 at which the fluid flow is again stopped is preferably about 125 mmHg. (16.7 kPa) for epidural injection, but can range from about 80 mmHg. (10.7 kPa) to about 180 mm Hg. (24.0 kPa) depending on the anatomical space of interest. The use of three pressure settings improves flow on / off control as the needle tip moves through various tissue types for any fluid-filled anatomical space capable of accepting fluid at low pressure, as opposed to tissues surrounding the anatomical space.

[00119] It is contemplated that a non-pharmaceutical medium is used to identify the epidural tissue space during the needle placement phase of an epidural injection procedure. Suitable non-pharmaceutical fluids include, for example, sterile saline, artificial cerebrospinal fluid, Ringer's solutions, 5% dextrose solution, or filtered air. After the epidural space of the tissue has been identified using a differential pressure, the injection fluid is exchanged for a pharmaceutical-containing fluid. The use of a non-pharmaceutical fluid during the needle placement phase minimizes or prevents the introduction of pharmaceuticals into non-target tissues.

[00120] Another feature of the proposed device and method is the objective nature of the pressure measured by a computer-controlled drug delivery device that monitors the pressure during all phases of the injection process. Thus, the attending physician no longer relies on subjective "feelings", but receives objective information about the absolute values ​​during each phase of this risky operation. Each phase of the method is enhanced by the ability to continuously monitor pressure while using intermittent drug fluid flow, thereby allowing adjustments to be made to improve injection safety and efficiency.

[00121] In another embodiment, the attending physician can release a predetermined maximum allowable pressure after the needle enters the fluid filled space and begins injection. As indicated above, prior to penetration of the needle into the epidural space, the fluid pressure is greater than 200 mmHg. (26.7 kPa), resulting in only a small amount of fluid being delivered, or no fluid at all. After penetration of the needle into the fluid-filled space, the pressure decreases to values ​​below zero and gradually rises to values ​​of about 1-10 mm Hg. (133.3-1333 Pa). This decrease in pressure initiates the flow of fluid from the injection device. At this point, the maximum pressure setpoint can be changed to a new, lower maximum. For example, the predetermined maximum pressure at which the flow of fluid is stopped can be reduced to 25 mm Hg. (3.3 KPa), which provides an additional level of patient safety in case of contact of the injection needle with the dura mater or withdrawal of the needle from the epidural space. The new target lower maximum pressure results in an earlier cessation of fluid flow and with a reduced ectopic injection volume compared to the initial target value. The change in the predetermined maximum pressure stopping the flow of fluid can be performed manually by the attending physician or automatically by means of a control element in the injection device.

[00122] It should be understood that the value of 200 mm Hg. (26.7 kPa) as the predetermined maximum target pressure for stopping the fluid flow is only an example, and a lower or higher target pressure may be selected at the discretion of the attending physician. In addition, the value of the second target pressure of 50 mm Hg. (6.7 kPa) at which fluid flow is resumed is given by way of example only and merely illustrative, so that a lower or higher target pressure can be selected at the discretion of the attending physician. The proposed principles and methods can be modified for injection into almost any anatomical area. Of particular importance in this embodiment of the method and device according to the present invention is the ability to determine and select preset pressure values ​​for generating an intermittent drug flow for diagnostic and therapeutic drug administrations.

[00123] The methods described herein are equally suitable for injection into human and animal tissue.

[00124] FIG. 5-6 is a schematic diagram of the arrangement of tools and electronic components. As shown in FIG. 5, the visual signal generator 100 may be coupled to the CPU 80 of the execution unit 50. In particular, as described above, the CPU 80 may include a separate light control circuit that is configured to control the lighting elements of the visual signal generator 100. In particular, the light control circuit can receive signals from the CPU or other elements of the execution unit, and can control the lighting elements in response to the received signal.

[00125] FIG. 6 shows an alternative block diagram of the system shown in FIG. 5. As shown in FIG. 6, the visual signal generator 100 is connected to the display screen 62 of the execution unit 50. In particular, the visual signal generator 100 may be connected to a USB hub located on the display device. According to this embodiment, the visual signal generator 100 comprises a light control circuit configured to receive signals from a display device and control the light to provide the necessary visual feedback as described above. For example, the visual signal generator 100 can be configured to operate as a remote projection screen onto which any image shown on the display screen 62 can be projected.

[00126] FIG. 9 shows an execution unit with an attached light source 100 projecting a light image onto a target surface of the patient's body and a portion where the needle is inserted into the patient's body. The light indicates that the needle has detected a fluid-filled cavity by a color change projected onto the patient's body surface.

[00127] The use of emitted light projected onto the surface of the patient's body provides many advantages that cannot be realized by other mechanisms. In particular, a light emitting element configured to emit light with different colors and / or patterns provides:

(i) a mechanism configured to objectively represent one or more specific pressure thresholds that cannot be conveyed by a continuous acoustic tone;

(ii) a mechanism designed to effectively notify an operator when pressure rises or falls, without subjective interpretation, by changing colors and / or patterns of light that are objectively visually recognizable as distinguishable indicators;

(iii) a mechanism for allowing the operator to focus his field of view on the treatment site, and in particular, a mechanism whereby viewing the display device's remote screen does not require confirmation with an audible tone or other signal;

(iv) an inexpensive mechanism for transmitting information without the need for a remote display screen or ancillary equipment;

(v) a mechanism that removes the limitations of acoustic feedback in an operating room where there are many competing sounds and tracking devices that can distract the operator and lead to medical errors; and

(vi) a mechanism that does not emit sounds that the patient can interpret as a cause for concern during the procedure.

METHOD FOR EPIDURAL ADMINISTRATION

[00128] A top view of the tool shows a recessed cavity 52 and a recess 56, collectively referred to as a syringe receptacle, which allows the execution unit 50 to receive a standard 20 cc syringe 18. The piston recess 56 contains a movable armature 90 and platform 58, which cooperate with the thumb rest or flange 72 of the disposable syringe 18. The mechanism that interacts with the thumb rest has a plurality of spring-loaded hooks 60 as shown in FIG. 1 that automatically grip the thumb rest of the syringe.

[00129] As shown in FIG. 1, to engage the thumb rest 72 of the syringe, the spring-loaded hooks 60 move outwardly over the syringe stop 72 and then engage with the syringe stop in a hook manner. As a result of this action, the syringe stop locks as shown in FIG. 1, allowing the platform 58 to move the syringe piston 70 in any direction to perform aspiration. In addition, a strain gauge is integrated into the syringe fitting 90. The valve body 90 uses optical and mechanical means to identify the position of the syringe and allows the volume of fluid in the syringe to be calculated.

[00130] Step 1: The power of the execution unit 50 is turned on by a corresponding button on a separate side panel 64, as shown in FIG. 5, which contains the "On / Off", "Start / Stop", "Cleaning" and "Aspiration On / Off" buttons, as well as battery indicators. The On / Off button turns on the power to the execution unit and the LCD touch screen interface 62. On power-up, the syringe valve mechanism 90 automatically moves to a home position as shown in FIG. 1.

[00131] FIG. 1 armature 90 with a movable platform 58 with a receptacle 52, 56 for an abutment of the syringe for automatic interaction during aspiration is connected to a movable armature for a syringe located on the upper part of the execution unit.

[00132] The top of the execution unit has a syringe receptacle that contains stoppers or clips 54 located on its surface. These stops 54 interact with the surface of the syringe barrel 18 when the syringe is positioned in the receptacle to create an interconnection between the syringe and the receptacle.

[00133] Step 2: The execution unit 50 uses the disposable injection assembly 10 shown in FIG. 3, which contains the following system components.

[00134] Syringe 18: In a preferred embodiment, a standard 20 cc syringe from Becton Dickinson, Inc. is used. The design is not limited to a specific size or volume of the syringe. The operator loads the syringe with fluid from a suitable sterile container, such as a multi-dose drug vial or disposable glass ampoule. The operator can load the syringe completely or partially load the syringe as the auto-detection means determines the amount of fluid in the syringe.

[00135] In a preferred embodiment, an in-line pressure sensor 20 is used, such as a Meritrans® in-line pressure sensor from Merit Medical, South Jordan, UT. It is contemplated that a strain gauge in a syringe assembly can provide information corresponding to fluid pressure and eliminates the need for a secondary pressure transducer.

[00136] The hypodermic needle 24 may be a Tuohy needle, such as a 20Gx3.5 "Tuohy needle from Becton Dickinson, Franklin Lake, NJ. The sterile tubing set is a 22-48" type blood pressure tube such as a sterile tube from ICU Medical, Inc., San Clemente, California.

[00137] Any means for transmitting and communicating to the central processor of the execution unit, including but not limited to infrared radiation, Wi-Fi, Blue Tooth, or other wireless means, can be used as the identification connector 12. Verification of the disposable assembly can also be accomplished using automated marking or markup, such as bar-coding the injection assembly 10, and using a barcode reader to scan the barcode. The barcode may contain an element that acts as a key so that when the system receives a scan of the barcode of the corresponding injection unit, it opens the execution unit 50 for use. The identification connector 12 communicates with the execution unit CPU 80 to provide information related to the disposable injection assembly 10.

[00138] It is contemplated that additional information may be encoded in the identifying connector 12, such as but not limited to: drug information such as drug name and formulation, drug manufacturer, lot number; information related to the disposal of consumables; information related to the expiration of the medicinal product; information related to the sterility of the disposable kit; and the date and time that the identifying connector was used.

[00139] In a preferred embodiment, a 20 cc syringe 18 is connected to a Meritans model pressure transducer 20 with an identifying connector 12 attached and a set 22 of 48-inch blood pressure tubing. At the distal end of the tubing set, a Tuohy needle 24 (hollow) is attached as shown in FIG. 1, 2 and 7.

[00140] Step 3: After inserting the syringe 18 into the syringe receptacle, the operator views the initial screen 62 with the message "Load syringe and press Continue". The touch screen interface 62 allows the operator to press the "Continue" button, thereby automatically engaging the aspiration receptacle with the thumb rest of the syringe.

[00141] Step 4: The operator inserts the needle into the patient's body at the target site. As the operator advances the needle, the system detects feedback pressure in the needle and a visual signal generator projects a signal based on the detected pressure. The visual signal changes as the detected pressure changes. The operator continues to advance the needle using visual signals from the visual signal generator to guide needle insertion.

[00142] In the above example, the feedback from the visual signal generator is based on the detected pressure. However, as indicated above, the pressure depends on the flow rate of the fluid exiting the syringe. Accordingly, it should be understood that the signal from the visual signal generator may be based at least in part on the flow rate of fluid from the syringe into the patient's body.

[00143] The automatic syringe detection function uses the auto-engaging aspiration receptacle retention hooks to confirm that the correct size syringe is selected. Confirmation is set based on the size of the thumb rest and the diameter between the hooks of the auto-engaging aspiration receptacle. If the size of the syringe and the size of the receptacle do not match, the hooks will not engage. The loaded syringe is initially detected by a load cell contained in the syringe arm of the execution unit. The forward movement of the syringe armature is automatically stopped when resistance is detected at the thumb rest. The syringe armature then reverses the direction of movement after the spring loaded hooks engage with the syringe thumb rest. If a reduced bore syringe stop is used that is not the same size as a 20 cc syringe. cm, the hooks do not engage so the syringe is not detected. In response to an undetectable syringe, the system displays a warning message or gives a corresponding signal, and further use of the execution unit is terminated. For example, the light assembly 100 may emit a quick flash of a red warning light prompting the operator to correct the problem with the injection assembly.

[00144] The automatic syringe detection function uses an optical and / or mechanical sensor to detect signs of a syringe to thereby determine the volume of fluid in the syringe. The detected volume is shown on the display. Upon completion and confirmation of syringe detection, the system can automatically flush the tubing set with the appropriate volume of fluid to fully charge the disposable injection assembly 10.

[00145] In light of the above and as shown in FIG. 11, an exemplary method of use is described below, which includes using the functions of the visual signal generator 100 and the needle marker 344 along with the counter pressure to calculate the outlet pressure. The description below relates to an epidural procedure, but it should be understood that the method can also be applied to other processes, such as a peripheral nerve block procedure, in which fluid pressure in a needle is monitored.

[00146] Previously, the operator prepares the instrument, enters various parameters based on the patient information and the details of the procedure. In the present example, a hand-held unit 300 containing an epidural needle is used. The needle has marks at specific distances from each other, such as 1 cm sections that alternate between silver and black. The operator attaches the disposable tube 22 and pressure transducer 20 to the syringe 18. The visual signal generator 100 is then directed towards the patient so that the visual signal generator projects a light beam onto the patient near the target injection site. The data the operator enters into the system sets the required needle insertion rate, which also determines the back pressure, which will become part of the calculation when the system detects the outlet pressure.

[00147] The drug delivery tool 50 starts to operate and light is emitted from the visual signal generator 100. In this embodiment, a flashing light is emitted to provide a visual indication of how quickly the operator should advance the needle from one needle mark 344 to the next. For example, the visual signal generator 100 projects "green" light onto the patient's body surface for 2 seconds, during which 2 seconds the operator must slowly advance the needle to the next mark on the needle at the patient's skin surface. Then the light emitting source is switched to "black" for a very short period of time (0.1 sec). When the light switches back to "green" within the next two seconds, the operator must advance the needle to the next distance defined by marks 344 on the needle.

[00148] The operator continues to advance the needle into the tissue of the patient's body at a certain pace, which is controlled by a blinking pattern. This pattern of 2 second green emitted light followed by a short period of no light continues as the pressure rises from point "A" to point "B" in the graph shown in FIG. eleven.

[00149] As the pressure rises between points "A" and "B", the back pressure value is included in the algorithm to adjust the outlet pressure value shown on the screen. During this period, the pressure rises with a flashing green light.

[00150] A visual indication of green blinking at a specific rate alerts the user to two aspects of the system: 1) The needle must be inserted at a specific needle insertion rate by coordinating the rate of skin penetration (which in turn provides the instrument with a constant known counter pressure ); 2) It notifies the operator that the pressure is increasing from 0 mm Hg. (0 kPa) up to 100 mm Hg. (13.3 KPa) according to this embodiment. During this period, the execution unit may discharge fluid from the syringe through the needle.

[00151] The operator continues to advance the needle into the patient's body towards the target layer, which in this embodiment is the ligamentum flavum, while performing the epidural injection.

[00152] When the pressure reaches the "B" point as shown in FIG. 11, the motor of the execution unit 50 is stopped because the pressure of the fluid has reached a predetermined pressure limit that was previously determined. When the motor stops, the execution unit no longer expels the drug from the syringe. When the pressure reaches this preset value, the instrument stops the needle insertion rate indication by flashing the emitted light.

[00153] This value, if necessary, can be changed by the operator (in this case, it is 100 mm Hg (13.3 KPa)).

[00154] Upon reaching point "B", a special emitted visual alert is provided. Various colors can be used for it; according to this embodiment, white light is emitted in this case. This light can be steady or flashing to indicate that the maximum pressure has been reached.

[00155] Despite the fact that between the point "B" and "C" the pressure remains at 100 mm Hg for some time. (13.3 kPa), there is no additional visual information related to the movement of the needle. The operator, if necessary, can observe on the screen that the pressure value is 100 mm Hg. (13.3 KPa).

[00156] The operator continues to advance the needle so that the tip of the needle at point "C" enters the epidural space. A decrease in pressure occurs as the needle is inserted into the epidural space and the actuator motor 50 begins to displace the plunger, thereby displacing the drug from the syringe. However, the pressure decreases between points "C" and "D". The light emitting source emits a flashing red light, indicating that the pressure is dropping.

[00157] At point "D", the pressure reaches the inflection point and starts to increase again. Starting at point "D", the light emitted changes between points "D" and "E" and is now represented by a blinking green light that flashes at a pre-set 1 second rate, different from the needle insertion rate between points "A" and "B ".

[00158] At the point "E" of the inflection, the pressure again begins to decrease, and at this point the generator again changes the visual signal to a flashing red light before determining the predetermined discrete pressure value at the point "F".

[00159] After reaching point "F" and falling pressure below 40 mm Hg. (5.3 kPa) a constant red color is emitted between points "F" and "G", indicating that the outlet pressure is between 40 mmHg. (5.3 KPa) up to 20 mm Hg. (2.7 KPa).

[00160] After passing the "G" point, the pressure drops to a value of 20 mm Hg. (2.7 kPa), and a solid blue light is emitted, indicating that the pressure has reached the minimum value and the outlet pressure is in the range of 20 mmHg. (2.7 KPa) to 0 mm Hg (0.0 KPa).

[00161] At this point, the identification of the epidural space is confirmed by the operator and the use of the instrument ends.

ELECTRIC STIMULATED INFUSION SYSTEM

[00162] As shown in FIG. 10 and 13, the medication infusion system that contains electrical stimulation elements is designated 405. The system 405 is adapted to be used in a variety of procedures such as peripheral nerve blockade. System 405 contains a plurality of elements, which are the same elements as those described above in connection with the system denoted by reference number 5, or similar elements. Accordingly, elements in system 405 that are substantially similar to elements in system 5 have the same reference numbers.

[00163] The system 405 includes an injection unit 410 and a computer-controlled drug delivery tool 450, similar to an injection unit 10, and an execution unit 50 described above. The injection unit 410 contains an insertion needle 340 and is connected to an execution unit 450 which, during use, controls flow of fluid to the injection unit. System 405 also includes one or more output devices that provide data to a healthcare professional during a procedure to facilitate proper needle placement in a subject's body.

[00164] The system 405 is configured to locate an intrafascicular needle placement. The system is also configured to deliver the therapeutic drug to the intrafascicular location of the needle. The medicament may contain, but is not limited to, local anesthetic solutions such as corticosteroids, hydroxyapatite, combined reconstituting agents, sclerosing agents, and other drugs that are typically administered therapeutically into fluid-filled tissue spaces.

[00165] The intrafascicular position of the needle is the position in which the tip of the needle penetrates the perineurium such that the tip of the needle is located within the nerve bundle. The extrafascicular position of the needle is the position in which the needle is located anywhere outside the perineurium of the individual nerve bundle, which may contain an external epineurium or even a paraneurium, thus defined as completely extraneural.

[00166] The nerve can be permanently damaged if the tip of the needle penetrates the nerve bundle, and then the fluid under hydrostatic pressure causes changes in the neural and vascular tissues in the nerve bundle. This is because the outer layer of the nerve bundle is a protective layer of a relatively rigid, rigid protective structure. It protects the main components of the nerve, i.e. axons that are tightly packed in a bundle. In other words, the bundle of nerves is a densely packed formation with a thickened protective sheath. A bundle of nerves does not easily deform when stretched or compressed. Thus, the fabric's tendency to absorb fluids is extremely low and / or negligible. Penetration of the needle into the bundle of nerves does not necessarily cause permanent damage to portions of the axon, but the combined effect of penetration of the needle and the increased pressure within the nerve bundle caused by the infusion of fluids into the bundle can damage the capillary bed. In addition, fluid pressure-induced strangulation of axonal microcirculation prevents the immediate supply of nutrients following such physical trauma, resulting in initial necrosis. The cumulative effect of necrosis leads to an inflammatory response in attempts to initiate wound healing from an initial pressure-induced injury that continues to expand or accumulate to potentially irreversible damage.

[00167] However, in some cases, deliberate intrafascicular needle placement is desirable and necessary. Such cases include unrecoverable phantom pain after limb amputation. In addition, overactive neural stimulation of a specific limb can sometimes lead to treatable pain, and is another circumstance that requires intentional intrafascicular needle placement and drug delivery. Accordingly, system 405 and its use provides a method and apparatus for effectively distinguishing between extrafascicular and intrafascicular needle placement.

[00168] The injected fluid is absorbed through the tissue at different rates. As a result, the pressure of the fluid changes. Thus, fluid pressure (or internal pressure, referring to tissue resistance pressure) is an indicator and can be used to identify different tissue types.

[00169] System 405 allows the physician to accurately identify fluid filled tissue space while limiting drug delivery to non-target tissues. This applies to both diagnostic and therapeutic procedures. System 405 uses fluid pressure from the needle or catheter after placement of the needle / catheter in tissue to identify placement accuracy and monitor placement during injection or aspiration.

[00170] In particular, system 405 includes one or more output devices for providing audible and / or visual feedback regarding the detected fluid pressure in the insertion needle. The operator uses visual feedback for guidance during insertion needle placement. As shown in FIG. 13, the first output device may be a screen of a display device such as an LCD display device for displaying data to assist an operator. In addition, a second output device can also be provided. For example, the second output device can be a speaker for outputting an audio signal.

[00171] System 405 includes an injection assembly 410 that contains a syringe 18 and a sufficiently long length of flexible tubing 22 having a first end connected to a syringe and an insertion needle 340 connected to a second end. Thus, fluid from the syringe can be displaced through the tube 22 into the needle 24. The injection assembly 410 also includes a pressure sensor for detecting the pressure of the fluid in the injection assembly. The pressure transducer may be located at one of various locations to measure a pressure that correlates with the fluid pressure at the tip of the needle 340. In this case, the pressure transducer 20 is an integral fluid pressure transducer attached to the syringe 18 between the syringe and tubing 22. Thus , the pressure sensor 20 senses the pressure of the fluid when the fluid exits the syringe and enters the tube 22 to which the insertion needle 340 is connected.

[00172] The injection unit 410 may also include a reusable hand unit 300 to which a needle is attached. As shown in FIG. 10, an insertion needle 340 is connected to the front end of the handpiece, and a tube 22 is connected to the rear end of the handpiece. The handpiece 300 may include means to assist the operator during the insertion process, as detailed below. In addition, the handpiece 300 may be configured to provide electrical stimulation, as detailed below.

[00173] The injection unit can be manually operated to inject fluid. However, in this case, the flow of fluid from the injection assembly is controlled by a computer controlled drug delivery system 450, as described in detail below. An output cable 21 connects the pressure sensor 20 to the drug delivery system 450 so that the drug delivery system can monitor and optionally change the flow of fluid from the syringe in response to data from the pressure sensor 20. The pressure sensor 20 may be connected in series between the front end of the syringe barrel 18 and the first end of the tube 22. One exemplary connection is the luer-lock connection of the pressure sensor 20 to the tip of the syringe. The connection can be a threaded connection and / or a non-reversible threaded connection such as a LuerLok type connection. In another embodiment, the pressure transducer 20 may be permanently attached to the syringe by plastic welding or chemical bonding such as with an adhesive. Thus, the instantaneous effective fluid pressure in the drug delivery line 22 is recognized and used in accordance with the instrument, thus providing a close approximation of the instantaneous fluid pressure at the point or tip of the needle 340 and thus at a location in the patient's body. where the tip of the needle is located. The electronic pressure sensor 20 provides pressure data via electronic data cables that are connected directly to the central unit 50 to collect pressure measurements.

[00174] As described above, the system 405 may include a fluid delivery system 50 for providing controlled drug flow to the injection assembly 10. Preferably, the fluid delivery system is an automated system, and in this case is a computer controlled fluid delivery system called executing block 450, which acts like the execution block 50 described above, unless otherwise indicated in the description below.

ELECTRIC STIMULATION

[00175] The system 405 may also include an electrical stimulation element 334 that provides electrical nerve stimuli to target tissue in a patient's body. The electrostimulation element is a conductive element connected to the hand-held unit 300. The electrostimulation element is configured to deliver an electrical discharge of low intensity (i.e., about 0.15 mA to about 2.0 mA) and short duration (i.e., pulses of duration approximately 0.1 ms to 1 ms). Electronic stimulus elements provide stimuli for a short time (ie, approximately 1-10 seconds).

[00176] The electrical stimulator can be an external member or an internal member. For example, in FIG. 10 and 13 show one embodiment that includes external electrical stimulators. A conductive element 334, such as a conductive cable, connects the handpiece 300 to the stimulus generator 335 so that electrical stimuli can be transmitted from the stimulus generator to the handpiece. In turn, the hand-held unit is connected to an element capable of delivering an electrical discharge to the tissue. For example, the needle 340 may be made of a current-conducting material and the handpiece may include a connection to the needle providing a path for electrical current from the conductive element and the needle. In another embodiment, a conductive element, such as a wire, can extend along the needle and the needle can be electrically isolated from the wire. For example, the needle can be made of an electrically insulating material. An example of an external electrical stimulating element is an insulated needle sold under the trade name "Stimuplex®" or also a needle catheter sold under the trade name "Contiplex®C" by B. Braun Medical Inc., Bethlehem, PA.

[00177] In another embodiment, the system can use internal electrical stimuli. For example, the fluid introduced from a syringe can be an ionic solution that conducts electrical stimuli. The conductive element can be in contact with the fluid in the insulated needle. The needle can be made of various non-conductive materials. For example, the conductive element may extend along the path of the fluid at some point between the syringe 18 and the needle 340. For example, the conductive element can transmit electrical stimuli to the fluid at the rear end of the handpiece 300. If electrical stimuli are transmitted to tissue through the fluid, the needle 340 can be electrically isolated to minimize any leakage or loss of electrical charge through the sidewalls of the needle.

[00178] The electrostimulation element is connected to an electrical stimulus generator 335, which is an electrical source adapted to transmit an electrical discharge or impulse to the stimulating element. A stimulus generator can be located in execution unit 450 as shown in FIG. 13. With this arrangement, the stimulus generator 335 is coupled to the central processor of the execution unit such that the central processor provides electrical signals to control the operation of the stimulus generator. In another embodiment, the stimulus generator may be a separate element having a separate power source and separate control.

[00179] The system 405 may also include a user-controlled input device 470 that allows an operator to provide an input to control the system. The delivery device can be any of various devices, such as a hand or foot control device, that provides a means for the operator to start and stop drug delivery and to vary the delivery rate from one drug delivery rate to a second or third different predetermined delivery rate. drug. In another embodiment, the input device may be a button, touch screen, mouse, keyboard, or microphone for issuing audio input commands. In addition, the system may include multiple input devices to allow an operator to enter multiple inputs for various steps in a procedure. For example, the system may include a first input device, such as a foot pedal, that controls the flow of fluid through the device. Activation of the footswitch (i.e., depressing the switch) sends a signal to the execution unit's CPU, which in turn sends a signal to the motor to drive it so that fluid flows from the syringe into the needle 340 when the pedal is activated. In yet another embodiment, depressing the foot pedal at the first time point can control the start signal to start the fluid flow, and the fluid can continue to flow until the operator depresses the foot pedal again. Thus, the second push acts as a stop signal to stop the fluid flow. In addition, the system may include a second input device, such as a touch screen, so that when electrical stimulation is applied to a patient, the operator can enter an indication as to whether a muscle convulsion has been detected or the patient has noticed a sensation. In addition, the primary or secondary input device may be operated by a button, such as a button 325 on a handpiece. Activation of the control button 325 may signal the central processor to provide responsive input during the procedure.

[00180] As described above, the fluid pressure is used to control the operation of the system 5. Similarly, the fluid pressure is used to control the operation of the peripheral nerve block system 405. For example, system 405 can provide a signal to an operator if the fluid pressure exceeds a threshold, thereby indicating that the needle may be located intrafascicular. As described above, there are various methods for calculating the fluid pressure at the exit of the needle.

OPERATING METHOD OF THE SYSTEM CONTAINING ELECTRIC STIMULATION

[00181] The following describes an exemplary method of administering an epidural injection to a patient using the system described above. It should be understood that the present system is not limited to use only in peripheral nerve block procedures. Accordingly, it should be understood that the principles and methods described below can be readily implemented for injection into tissues and anatomical regions in a variety of applications and procedures.

[00182] The system can be used to determine if the needle is located in the bundle of nerves (ie, if it is located intrafascicular). The system performs determination based on the combination of several variables. First, if the needle pierced the endoneurium, the fluid pressure would be quite high because the axons are tightly packed into the endoneurium. In addition, if the needle pierces the endoneurium, the operator is likely to observe a noticeable response to electrical stimulation applied to the patient at or near the needle tip. Thus, if the operator receives a high fluid pressure alert and then uses electrical stimulation and notices a response, it is likely that the needle is positioned intrafascicular and thus needs to be repositioned. So, the system can work as follows.

[00183] As shown in FIG. 14, at step 500, the operator selects procedure parameters such as an upper threshold and / or fluid flow rate and / or needle advancement rate. For example, the operator can set an upper threshold pressure such as 300 mmHg. (40.0 KPa). In another embodiment, an upper threshold may be set in the system when an operator selects the type of procedure for which the system is to be used. Likewise, the operator can select the flow rate of the fluid through the needle, or the flow rate can be set automatically when the operator selects the type of procedure. In addition, the operator can select the duration of the electrical nerve stimulation during application. After selecting the procedure parameters, the operator provides an indication that the procedure should begin. For example, an operator can press the "Start" button on the execution block.

[00184] In step 510, the operator advances the needle into the patient's body. As described above, the needle can be advanced at any of a variety of insertion rates such as 3-10 mm / sec. Preferably, the needle is driven at a substantially constant speed. Accordingly, at step 510, the operator can insert the needle at a constant velocity, guided by indicator 315, as described above.

[00185] In step 515, while the operator advances the needle, the system continuously determines the feedback pressure in the needle and provides visual or audible feedback about the determined pressure. The visual signal changes when the detected pressure changes.

[00186] At block 520, the operator continues to advance the needle until the system issues a signal indicating that the fluid pressure has exceeded the high threshold.

[00187] At step 525, it is determined that the fluid pressure is above the high threshold so that the system issues an audible, visual and / or tactile warning signal. In response to a signal indicating that the fluid pressure has exceeded the upper threshold, the operator stops advancing the needle. In addition, the execution unit can stop the motor to stop the flow of fluid to the needle.

[00188] In step 530, an electrical nerve stimulation signal is applied to or near the tip of the needle 340. For example, as described above, electrical nerve stimulation can be transmitted to a conductive member located near the tip of the needle. Electrical stimulation of the nerve can be provided automatically by the system in response to fluid pressure exceeding an upper threshold. For example, when the pressure of the fluid exceeds an upper threshold, the system sends a signal to the operator. In addition, at that point or after a short delay such as 1-3 seconds, the system can perform electrical stimulation of the nerve. In another embodiment, an operator can apply electrical stimuli by providing an introductory prompt, such as a button press or a verbal command. In response to the operator's prompt, electrical nerve stimulation is applied to the patient. In other words, when the pressure of the fluid exceeds the upper threshold, the system prompts the operator to apply an electrical discharge, and in response to this signal, the operator applies an electrical discharge.

[00189] In step 540, the operator monitors the patient for any clinically observable response, such as muscle convulsion. The operator then provides input to the system indicating whether an observed reaction has been detected. For example, the operator can press the first button if he noticed a convulsion, or the operator can press the second button if he did not observe the convulsion. If the operator confirms the observed response, the method proceeds to block 545. If the operator has not confirmed the observed response, the method proceeds to block 560.

[00190] At block 560, the system provides an alert to the operator. The alert can be visual, audible and / or tactile. An alert alerts the operator that the needle may be positioned intrafascicular. For example, the system can provide an audible warning audible announcement such as the word "Warning" while providing a flash of light on the handpiece.

[00191] In step 550, the operator removes the needle and re-inserts it in an attempt to position the needle in the target area without piercing the perineurium. Thus, the method restarts at block 510.

[00192] If no response is observed at 540, the method proceeds to 560. At 560, the system provides a signal to the operator indicating that the needle is properly positioned for injection (ie, the tip of the needle is extrafascicular). For example, the execution unit 50 may provide an audible signal, such as an audible reproduction of the word “Continue,” or provide a visual signal, such as the word “Continue,” on the display screen of the execution unit or hand-held unit.

[00193] In step 565, the speed of the fluid is increased to a second speed that is higher than the first speed. The operator can enter a preliminary value that can be observed so that the operator can detect that the needle is properly positioned. After confirming placement, the operator can deliver a bolus (single dose) of fluid to anesthetize the patient. In another embodiment, an operator can deliver a bolus of fluid without entering a first value to verify needle placement. In either case, the fluid in step 565 is injected at a higher rate than the previous low rate. In yet another embodiment, in response to an indication that the upper pressure limit has been exceeded and an indication that no response is observed in response to electrical stimulation of the nerve, the execution unit can automatically increase the flow rate, for example, by increasing the engine speed.

[00194] Another advantage of the proposed device and method lies in the objective nature of the pressure measured by the computer-controlled drug delivery device, which is monitored during all phases of the injection process. Thus, the attending physician no longer relies on the subjective nature of the "sensation", but rather is provided with objective information about the absolute values ​​during each phase of this risky method. Each phase of the method is enhanced by the ability to objectively monitor pressure on a continuous basis.

[00195] It should be understood that the value of 300 mm Hg. (40.0 kPa) as the maximum target pressure for stopping the flow of fluid is just an example, and that a lower or higher target pressure may be selected at the discretion of the attending physician. The methods described herein are equally applicable to human and animal tissues.

[00196] Those of skill in the art will understand that the above-described embodiments may be made with changes or modifications without departing from the broad inventive concepts of the present invention. For example, in the above description, the system is described in the context of providing fluid infusion. However, it should be understood that the system can be used to position a needle while aspirating fluid-filled tissue. In particular, the injection device can be used to aspirate a fluid-filled tissue space after identifying said fluid-filled space has been determined. Aspiration can be used to retrieve a sample of tissue or extracellular fluid (i.e., cerebrospinal fluid, intra-articular fluid, blood, etc.) or can be used to determine the correct placement of the injection needle. During the aspiration procedure, the "inlet pressure" is measured in the same way as the pressure in the fluid-filled tissue space, which is characterized by a pressure drop. Likewise, false pressure drops are also identified using the aspiration procedure as the content of the internal tissue structure (i.e. cysts) is rapidly drained and the inlet pressure rises above the inlet pressure threshold.

[00197] Thus, it should be understood that the present invention is not limited to the specific embodiments described herein, but includes all changes and modifications that fall within the protection and principle of the present invention as defined by the appended claims.