Pressure/force computer controlled drug delivery system and the like

Field of the Invention

The present invention mainly relates to improvements in drug delivery, namely, systems for delivering drugs via subcutaneous injection / suction (syringes), providing intermittent, episodic or limited drug delivery (as opposed to continuous drug delivery via syringes). More particularly, the present invention relates to improved means for injecting and pumping subcutaneous drugs (liquids) by providing means and methods for controlling and controlling the interaction of a specific flow rate and pressure with fluid injection and suction for subcutaneous injection via a syringe.

Description of the Related Art

Infusion pump devices and systems are relatively well known in the medical field and are used for dispensing or dispensing medications to a patient. These may be compact pump housings or larger stationary pump housing assemblies. Dispensing of prescribed medications is described in the literature as dispensing by infusion tubes and appropriate catheters or the like when administered intravenously. These systems are constantly being upgraded to detect infusion line clogging. Blocking the line will cause an increase in pressure in the syringe. Systems are state-of-the-art designed to recognize a predetermined threshold or control pressure by means of occlusion pressure limits to ensure patient safety. U.S. Patent Nos. 5,295,967, 4,731,058 and 5,080,653 disclose systems (with syringes or the like) similar to those intended for use in intravenous drug delivery and, more particularly, for controlling occlusion during infusion. However, these systems do not provide the ability to deliver drugs via needle injection under the skin. In addition, these systems do not provide suction during drug delivery, which is a sanitary requirement for subcutaneous injections in an attempt to prevent the injection of a subcutaneous needle into the blood vessels.

Pain, tissue damage, postoperative complications have long been tolerated as a negative side effect using existing drug subcutaneous injection systems. This is widely supported in the literature of both dentists and therapists. Pain and tissue damage are a direct result of uncontrolled flow velocity in interaction with excessive pressures created by the delivery of drug solutions to tissues. It has been demonstrated that subjective patient pain is reduced by specific flow rates during drug delivery. It has also been scientifically demonstrated that certain pressures (too high without clogging as such) cause damage to specific tissue types. Therefore, it is important that the specific flow rate in interaction with the adjusted pressure range is maintained during fluid (drug) delivery during subcutaneous injection, protecting from subjective pain as well as tissue damage. It is also imperative that this system has the capacity to pump under velocity and pressure controlled conditions to eliminate the same negative effects during fluid movement. The US patent is cited here

No. 5,180,371, issued to Spinello, discloses an invention which enables the drug to be accelerated by a subcutaneous injection needle. However, the invention does not disclose means for determining, clarifying, or controlling pressure during drug administration.

In the early 1980s, several researchers (see, e.g., Rood, The Pressure Created by Inferior Alveolar Injections, British Decks J. 144: 280-282 (1978);

Wolton and Abbot, Periodontal Ligament Injection; a Clinical Evaluation JADA. (October 1981); Smith and Walton, Periodontal Ligament Injection; The Distribution of Injected Solution, Orai Surg 55: 232-238 (1983), clearly demonstrated and concluded that the pressure exerted by the injected fluid is important in preventing tissue damage and pain. Variability, different types of collagen, and connective tissue density define different levels of tissue sliding and elasticity. These changes are found between the objects under study and within the objects themselves. Rood in his 1978 article. stated that “the relationship between injection rate and pressure rise was clearly evident when 2.0 ml was injected with less volume loss. Several cases of high pressure and several unexpected low pressures have been observed. Many records have shown the disruption of the patient's tissue, and it is possible that these low pressures cause the fluid to no longer be present in a given area when the volume injected is similar to a predetermined volume of tissue. " Consequently, the flow rate does not appear to be directly related to the pressure at the time of insertion injection.

Smith and Walton described in their above-mentioned article that they performed a histological examination of the animal (dog families) using a technique to check the pressures of manual labor. They found that "the volume injected and the position of the needle are not always related to the distribution ... Medium to high injection pressure injection produces a deeper and more widespread dye penetration." This confirms that the pressure changes dangerously with the distribution of the solution in the tissue and that the volume is not always related to the pressure generated.

In a paper by Pashley, Nelson & Pashley, Pressures Created by Decks Injections (J Dent Res 1981) used a pressure transducer and a fixed flow rate created by a motor that controls a conventional syringe and clearly demonstrated that different fabrics have different tissue slippages. The pressure variability of the incision was statistically and clinically significant even at a fixed flow rate. Therefore, it can be concluded that they provided a huge variety of pressures using a »measured flow rate.¹

Pertot and Dejou, in their article "Ejects of the Force Developed during Periodontal Ligament Injections in Dogs (Orai Surg. Or. Med. Or. Pathol. 1992), described how they used a syringe coupled to a miniature force transducer and found a positive correlation between multiple tissues and syringe. a piston-driven force that measures the pressure generated on the periodontal ligament area by increased tissue activity. This experiment again demonstrates that pressure is an important factor in tissue damage and depends on collision resistance, not on the rate of solution flow to the tissue.

One of the goals of dental and medical care should be to treat patients in the most humane and painless way possible. The prerequisite for any treatment is to achieve the desired result without harming or causing the individual pain.

Therefore, in all areas of surgery, there is an important need for an injection system that can be used to control fluid without substantially causing pain and tissue damage to the patient.

SUMMARY OF THE INVENTION AND OBJECTIVES

To this end, the present invention is intended to minimize the subjective pain response and any potential damage to the patient's tissue caused by improper pressures produced by the administration of drugs by subcutaneous injection needle.

An additional purpose is to provide these benefits through the interchangeability of various drug sources, ie standard syringes as well as anesthetic cores or capsules.

An additional goal is to provide a system that can be easily used with very little training in physician practice.

A further object is to provide a system of the type discussed above having a substantially disposable part.

An additional objective is a system that can perform not only injections but also intrinsic suction and / or biopsy with the ability to control both velocity and pressure.

An additional object is to provide a system that automatically detects and uses the outlet (or inlet) pressure as a controlled parameter for any size and combination of syringe, tube, or needle.

Prior art references that attempt to use a pressure transducer to measure the pressure inside a syringe are known (see, for example, U.S. Patent No. 5,295,967). The main disadvantage of these systems is their inability to adapt the flow rate and / or pressure resistances of the fluid to the system or to the outlet pressure. (The outlet pressure refers to the pressure of the fluid flow just down the needle tip to the patient's body). In addition, prior art references do not provide any means for determining this outlet pressure. The present invention provides a microprocessor-based system that measures the pressure or force generated on the outside of the tissues and then uses these measurements to accurately determine the appropriate outlet pressure. In other words, with specific software, the system controls the output pressure and generates and maintains a specific flow rate, even when there are changes in system resistance.

The invention also provides a system that automatically compensates for any collision resistance in the system and which has been shown to affect flow rates and measured pressures. It is believed to be the first system capable of providing a well-defined flow rate and required pressure with respect to overall system resistance. It is argued that without this capacity, flow rates and outlet pressures for changing disposable assemblies consisting of different syringe, tube, needle sizes, and flow characteristics cannot be accurately obtained. An important feature of the system is that it controls and controls the pressure using a converter that generates a feedback parameter.

Briefly, according to the present invention, the fluid distribution system for injecting a fluid into a patient comprises a mechanical assembly and an electronic regulator. The mechanical assembly comprises an actuator and a disposable part consisting of a fluid holding device, such as a syringe, capsule and the like, and a fluid delivery sector comprising a tube connected to said fluid holding device and terminating in a needle adapted to be inserted into a dependent tissue. The actuator includes a housing with an internal motor and a casing to mount the fluid-containing device on the housing. The fluid reservoir has a reciprocating plunger. The sleeve is used to displace the piston with said engine. It is important that the transducer is used to determine the force or pressure in the fluid-generating device generated by the engine and used by the piston. If the liquid storage device uses a capsule, a probe shall also be provided to allow the capsule to be mounted in the same manner. The enclosure is arranged and constructed to accommodate syringes or capsules of a wide variety of sizes. The motor, the motor-coupled coupling, and the electronic regulator discussed below are located at least partially inside the housing for safety reasons.

The electronic controller is designed to control all system operations. The controller consists of a master microprocessor, which can be a standard standalone PC or laptop computer, and an internal executable that is commanded by the master microprocessor. The master microprocessor provides an interface with the clinician and collects data related to the mechanical assembly. The master microprocessor is also associated with a display used to provide instructions to the practitioner and to an input device that may include a keyboard, a touch screen, or an activated voice device for collecting information from the practitioner. The master microprocessor is further associated with memory that captures multiple databases, each database associated with a single disposable element as well as other parameters.

The fluid reservoir is filled and the assembly process is started to calculate, select, or obtain various operating parameters from a physician. The physician will also accurately determine fluid flow rates, peak discharge pressure, and total fluid volume to be prescribed. It then performs pneumatic control, such as using the foot pedal and activating the fluid flow.

Similarly, teams of physician practitioner and electronically voice commands can be initiated. During the assignment, the converter output is used to calculate the current fluid outlet pressure. As this outlet pressure approaches a certain threshold, the fluid flow rate is automatically reduced to avoid excessive outlet pressure, thereby ensuring that the patient does not experience unnecessary pain and tissue damage. Some optimal features are also provided, including suction, cleaning, or media change with or without air. '^:

Similarly, the system can operate on a biopsy, where inlet pressure and outflow or outflow rate are important controlled parameters.

Throughout the process, the practitioner is constantly provided with important information about the ongoing process, both visually and verbally, including current flow rate, total volume injected or withdrawn, outlet or inlet pressure, and other parameters. The executable microprocessor receives commands from the master microprocessor and generates the control signals needed to operate the motor.

Brief description of the drawings

FIG. 1 is a diagram illustrating the main components of a mechanical system of the present invention;

FIG. 2 shows an orthogonal view of the actuator;

FIG. 3 shows the main elements of the actuator;

FIG. 4 is a view of the actuator from FIG. 3 elements arranged in housing;

FIG. 5A is a top view of the housing without the bracket;

FIG. 5B shows an orthogonal view of a housing without a holder;

FIG. 6 is a view showing a clamp for mounting the syringe to the housing;

FIG. 7A shows a platform 14 of FIG. 2 top view;

FIG. 7B is a side view of the platform 14 of FIG. 2 and FIG. 6 view from above;

FIG. 8 is a side elevational view of a prior art core;

FIG. 9 is a schematic side view of a sampler using the core of FIG.

with the system according to Figs. 1-7; i

FIG. 10 is a block diagram of an electronic regulator;

FIG. 11 is a schematic diagram of a main flow controller of the system of FIG. s for operation; »** '*

FIG. 12A illustrates a typical display showing various options available for 3 ~ disposable elements;

FIG. Fig. 12B shows a typical display summarizing operating characteristics and parameters for a particular procedure;

FIG. 13 shows a typical display shown to the practitioner during preparation;

FIG. 14 is a graphical representation of control signals received from the foot pedal;

FIG. 15A and FIG. 15B depicts typical time curves of fluid flow and outlet pressure, respectively;

FIG. 16A and Figs. 16B is a graph of fluid flow versus outlet pressure versus time when said pressure is above threshold;

FIG. 17 shows a flow diagram for suction;

FIG. 18 shows a flow diagram for filling the syringe;

FIG. Figure 19 shows the syringe and related equipment required for filling;

FIG. Fig. 20 shows a flow diagram for determining a typical component to determine the outlet pressure.

Detailed Description of the Invention

The present invention relates to a delivery system for drugs, such as anesthetics, or to suction delivery, for example, for biopsy, in an effective manner which at the same time ensures that pain is minimized to the patient. The system comprises a mechanical unit operable with an electronic regulator.

The mechanical assembly is illustrated in Figs. 1-9 and the electronic regulator is shown in Figs. 10-18.

The drug delivery system 1 constructed in accordance with the present invention comprises an actuator 2, a delivery tube 3, and a handle 4 terminating with a needle 5. More particularly, the syringe 6 (or other fluid reservoir) is mounted on the actuator and one end of the tube 3 is connected to the syringe. 6. The actuator 2 actuates the piston 7 to selectively displace the liquid through the handle 4 and the needle 5 of the tube 3, or to invert the liquid. The actuator 2 is connected to an external controller to select various operating parameters, discussed in more detail below. This external regulator may be mounted on the actuator housing or as a separate control unit 8 connected to the actuator 2 by cable 9. The control unit 8 may be, for example, a personal computer or a laptop computer. Alternatively, the control unit 8 may be internal.

Details of the drive mechanism 2 are shown in Figs. 2-5. Starting from FIG. 2, the actuator 2 comprises a housing 10 with an upper surface 11 and an intermediate surface 12 located below the upper surface 11. Rails 13 are formed on the intermediate surface 12 and extend along the axis of the housing 10. The platform 14, which is arranged on the rails 13, can move back and forth parallel to said longitudinal axis, as described in more detail below.

On the upper surface 11, it is better to see FIG. 5A and FIG. 5B, there are two parallel long grooves 15 and 16 and a groove 17 formed between them. The end of each groove has extensions 18 facing each other. The groove 17 ends at the transverse opening 19.

The notches 15,16 are driven by the clamp 20. As can be seen from FIG. 6, the clamp 20 generally has a C-shaped housing 21 terminating with legs 22 facing each other and a wall 23. The bolt 24 with the head 25 passes through a threaded opening (not shown) in the wall 23 and ends with the claw 26.

The clamp 20 is so constructed and positioned that its legs 22 fit into the extensions 18 and allow the clamp to move horizontally in the indentations 15,16.

A groove 28 is formed on the upper surface 27 of the platform 14 (shown in more detail in Figs. 7A and 7B), which has a split key groove 29 on one side.

The motor 30 (Figures 3 and 4) is securely mounted inside the housing 10. A worm screw 31 is threaded through the motor 30. The worm screw 31 is arranged such that, when the motor 30 15 is actuated, the screw 31 moves in one direction or another, depending on its direction of rotation, parallel to the longitudinal axis of the housing 10. One worm screw 31 galW 'is fixed to a support 32 connected to the platform 33. The load chamber 34 is disposed between the platform 33 and the support 32 for transmitting and evaluating the force between the support 32 and the platform 33. The loading chamber 34 is bidirectional and can therefore measure both pressure and tension, depending on whether the worm screw 31 moves to the left. or to the right as in Figs. 3. Two short bars 35 are used to connect the support 32 to the platform 33 and prevent transmission of the engine-generated torque to the platform 33.

Two columns or rods 36, 37 extend between the platforms 14 and 33 and secure these elements together. These rods 36, 37 are slidably supported on housing 10 by two pairs of bushings 38, 39. Except for these bushings, platforms 14 and 33 slide inwardly and outwardly of housing 10. Rods 36, 37 extend through openings (not shown) in wall 40 located between surfaces 11 and 12. The rails 13 are hollow and matched to the worm screw 31 so as to enable the worm screw 31 to move along its axis in the housing 10.

Typically, the syringe 6 has a barrel 41 disposed in a groove 17 such that its finger loop 42 (shown in Fig. 6) lies in the opening 19. The syringe 6 also has a piston 7 slidable by a handle 43 inside the barrel 41. The handle ends at the finger rest 44. When the syringe 6 is in the groove 17, the finger rest 44 is in the opening 27 of the platform 14. In this position, the syringe 6 is secured to the housing 10 by pushing the legs 22 of the clamp 20 into the notch extensions 18 and sliding forward or sliding the clamp 20 to the left above the syringe 6 to the tip of the syringe barrel 41 at the opening 19. , push forward and squeeze the syringe barrel 6. The groove 17 serves to insert the syringe 6. The syringe terminates in the closure 45 used to connect the syringe to the tube 3.

It is to be appreciated that the motor 30, the support 32, the load chamber 34, the worm screw 31 and the platform 33 are housed inside the housing 10. The platform 14 is located outside the housing 10. When the motor 30 is actuated, as will be discussed later, it causes the worm screw 31 to move in one direction or another. In turn, the worm screw causes the platforms 14, 33 and the rods 36 and 37 to move together in the same manner, thereby forcing the piston 7 to move. The only elements that move out of the housing and into the housing are the rods 36, 37. Thus, the most vulnerable elements of the system are protected inside the housing from touching or spilling of liquids. In addition, the actuator 2 is adapted to handle syringes of various diameters and lengths. Similarly, the dispensing tube 3, the handle 4 and the needle 5 may be of any desired size.

In the following embodiment, the fluid is considered to be dispensed from syringe 6, so either the manufacturer must pre-fill the syringe with the liquid 6 or the physician or assistant should fill it in place prior to any action. However, in many procedures, it is more desirable to provide an injectable liquid in the core, such as the core 46 shown in FIG. 8. As can be seen from this Fig., The core 46 is in the form of a cylinder 47. On the one hand, the barrel 47 is provided with a plunger 48 of rubber or similar elastic material which can be slid back and forth on the barrel 47, optionally releasing the fluid contained therein. On the other hand, the core is a sealed membrane 49 which must be pierced before the contents of the core are released.

FIG. Fig. 9 shows the pickup 50 allowing the actuator from Figs. 1-7 to dispense liquid from the core 46. The pickup 50 has a holder 51 adapted to hold the core 46. The holder 51 has a first end comprising a connector 52 (e.g., a Luer connector) for connecting the pickup 50 to the supply tube 3. is a mandrel 53 constructed and disposed to pierce the membrane 49 when the mandrel 46 is inserted into the holder 51. At the other end, bracket 51 has radial projections 54 to engage bracket 51 with actuator 2. The core bracket 51 just described is disclosed in Application SN 09 / 028,009, filed Feb. 23, 1998, entitled "Tooth Grinding and Injection Assembly," herein incorporated by reference. links.

The pickup 50 further comprises a connecting member formed as a mandrel 55 with a hook or hook 56 at one end, at the opposite end with a thumb pin 57. The mandrel 55 passes through a cap 58 with protrusions 54 mounted on respective brackets 51 (not shown). in cap 58:

The cap 58 has a radial tab 59 about the finger lugs 42 in the shape of a standard arithmetic syringe 6. 3T

In order to mount the core 46 on the actuator 2, first the core 46 is pressed into the bracket 51 by its rear end. Once the core 46 is housed in the holder 51, the stem 55 is aligned along the axis of the holder 51, and then its mandrel 56 is pushed into the piston 48 until they engage snugly. The core 46 then moves toward the connector 52 until the pin 53 pierces the membrane 49, allowing the fluid contained therein to escape. In order to ensure that the liquid does not spill, the tube 3 may be pre-mounted on the connector 52, but this tube is provided for clarity in FIG. 9 omitted.

Instead of the hook 55, a plunger 60 may be attached such that, when the plunger is pushed into the holder 51, a vacuum or pressure connection is formed between it and the plunger 48. As a result, longitudinal movement of plunger 60 forces the plunger 48 to follow it. ejects or enters fluid into the system.

The cap 58 is then connected to the holder 51 by pushing the projections 53 into the corresponding recesses in the cap 58, thereby connecting the cap to the holder 51. The core 46 and the receiver 50 of this shape are similar to the syringe 6 and can be mounted on the actuator of FIG. 1-7, similar to a syringe 6, by clamping a cap 58 engaging a tab 59 in the opening 19 and engaging the thumb 57 with a notch 28 on the platform 14. Using the pickup 50 in this position, a motor 30 can be used to push or pull the stem 55 and piston 48 into the core 46 either by a hook 56 or a plunger, thereby forcing the fluid to escape or aspirate as desired. The hook 56 (or piston) formed on the end of the stem 55 guarantees proper coupling and rigid connection of the stem 55 to the piston 48, thereby ensuring that the piston 48 moves in the direction of the stem 55 and the platform 14 in both directions.

FIG. 10 is a block diagram of the electronic controller 61. The controller 61 is comprised of two microprocessors: a master microprocessor 62 and an executable microprocessor 63. The executive microprocessor 63 is used to receive signals that actually control the motor 30 and collect information relating to the position of the platforms 14, 33.

The master microprocessor 62 is used to store information relating to system interruptions including the syringe 6 and its contents, the knob 4 and the like, and to generate control signals for the executable microprocessor 63 necessary to operate the motor by supplying the contents of the syringe 6.

The physically executable microprocessor 63 and its circuit are housed in a housing 10. The main microprocessor 62 is incorporated into a control unit 8 which is connected to the housing 10 by a cable 9 as shown in FIG. 1.

As can be seen from Figs. 10, the microprocessor 62 is coupled to a memory 64, 25 to an input device 65, a display device 66 and an interface 67.

Memory 64 is used to memorize programming and data for the master microprocessor 62. Specifically, memory 64 is used to memorize six or more data banks, each of these banks for information such as: (a) syringes;

(b) pipeline; (c) needles; (d) liquids; (e) control mechanism parameters; and (f) templates that include a plurality of parameters for performing certain procedures.

Each of these parameters is used to determine the control signals generated by the executable microprocessor 63. Each of these databases stores the respective parameters of various commercially available products, or alternatively, parameter data obtained using a specific algorithm. The information related to the various elements is input in some form through the input devices 47 and confirmed by the display devices 66. These input devices may include a keyboard, touch screen, mouse, as well as a microphone. If a microphone is used, voice commands are interpreted in a voice recognition circuit 68.

Display unit 66 is further used to provide references as well as instructions on how the system 1 operates. Master microprocessor 62 generates operating commands for motor 30 and transmits to interface 67. The microprocessor 62 also provides the speaker 69 with a variety of spoken messages, including pre-recorded speech or synthesized words (generated by voice synthesis circuit 70), melodies, and the like, providing instruction to the practitioner and other information about the system and its components. doctor 's practitioner looking at the screen all the time.

The executive microprocessor 63 receives all commands via cable 9 or other communication means and interface 71.

One or more position sensors 72 and an interrupted control circuit 73 are also coupled to the executable microprocessor 63. As mentioned above, the force between the platform 33 and the support 32 is measured by a load cell 34. This load cell may be, for example, a S400 load cell, made by SMD, Ine. of Meridien, Connecticut.

The footswitch 74 is also associated with a footswitch or pedal 74. Preferably, the footswitch 74 is comprised of an air chamber with a flexible sidewall, this sidewall being adapted to vary the volume of air and the pressure inside the chamber, depending on the operator. The pressure sensor (not shown) is part of the foot pedal and is adapted to provide information about said pressure to an executable microprocessor 63 via an appropriate analog-to-digital converter 75. This type of foot pedal is known in the art and therefore its details are omitted here.

The sequence of system operations is now described in conjunction with Figs. 11. Starting with step 76, the system itself is first assembled. Because this step involves the exchange of information between the practitioner and the outside world, it is performed by a master microprocessor 62.

Step 76 involves, first, entering this information with a medical practitioner:

type of syringe used, type 3 of the tube (ie size and length), type of needle used and name of the liquid in the syringe and other references. The physician may enter this information manually using an input device such as a keyboard or a touch screen on the display. Alternatively, a plurality of relevant items (e.g., syringes) may be retrieved and displayed from databases and then presented to a practitioner. The practitioner then uses a standard pointing device, such as a mouse or touch screen, to select the appropriate syringe. Alternatively, a voice command may be used for this selection. FIG. 12A shows a typical screen for setting or selecting a syringe. As shown on this screen, when selecting or setting up the syringe, its physical characteristics such as length, nominal volume, stroke length, syringe strength are selected from the database and displayed on the screen. When the needle and fluid are identified, their characteristics are selected and displayed in the same way.

Some information, such as tube length 3, must be entered manually as this is difficult for the system to determine. However, other information as well as various operating parameters are set automatically. For example, the identification of the syringe may be encoded on the part of the syringe and read by the system. As described below, one of the required parameters is the cross-section of the syringe region A. This is determined by dividing the volume by stroke or length of the syringe.

As soon as the information relating to the system components is entered or otherwise selected, another screen will be presented to the practitioner (Fig. 12B). This screen is used to either provide information to the practitioner or to allow the practitioner to enter additional operating parameters needed to complete the preparation for work.

Screen FIG. 12B has five defined areas 77, 78, 79, 80, and 81. The area 77 physician provides or selects some general information, including determining the template to be used for this procedure, i.e., "PERIODONTIC INJECTION". Zone 78 - Parameters from Screen Fig. 12A is repeated in truncated form with information on syringe, needle, tube and liquid.

In Zone 79, the practitioner selects the type of process and requires (for example, injection) high and low flow rates, optimal pressure limitation. As mentioned earlier, this last parameter is very important as it controls the pain and tissue damage that the patient may experience during the procedure. Additional parameters such as flow rate at filling, suction volume and flow rate, purge volume and flow rate can also be selected in this zone.

In area 80, the practitioner determines the total amount of fluid to be dispensed, whether (a) the syringe is filled, (b) or inflated; or (c) Is filled without air. In this area, the practitioner also chooses whether to use suction or not. Finally, zone 81 is used to determine various parameters calculated from previously obtained or selected information, including system volume, flow rate maximum, '* pressure maximum, and the like.

In one embodiment of the invention, the system, more particularly the master microprocessor 62, uses these parameters to select from a template database a template that determines the sequence and programming characteristics required to deliver fluid through a needle at the required or optimum rate. The template for each syringe - needle set is calculated and memorized earlier. These templates have unique characteristics for each type of drug injection procedure. For example, the pattern for periodontal ligament injection is different from the injection for cranial anesthesia. Only a single template group or family associated with a specific procedure can be memorized in the main microprocessor memory, since no other such templates are needed.

Alternatively, the master microprocessor 62 may be programmed to perform the calculations required to generate these templates. However, it has been observed that for most applications, templates are pre-computed, programmed, and stored in a database, as discussed previously.

Once the preparation procedure has been completed, a test is performed in step 82 to determine whether the practitioner requires the syringe 6 to be filled using the device or not.

In most cases, it has been observed that the practitioner either prefills the syringe by hand or uses a pre-filled syringe or cartridge. If the syringe is not filled or loaded by a device, then in step 83, the master microprocessor 62 sends a command to the executable microprocessor 63 to push the platform 14 to its original position.

Referring to FIG. 10, the microprocessor 63 is coupled to the load cell 35 via an analog-to-digital converter 84, a free-directional memory 85, an erasable programmable read-only memory 86, and a limiting sensor 72. Using the information obtained from these elements, via the interface 71, the executable microprocessor 63 controls the operation of the motor 30. More specifically, the executable microprocessor 63 operates through an actuator circuit breaker 87 which generates step pulses for motor 30, causing it to rotate in one of two directions at different angular accelerations. The frequency of these pulses determines the motor speed. Different speeds can be used for high flow rates, low flow rates for cleaning, suction or filling. The physician-practitioner selects values ​​for all of these speed parameters, and then the microprocessor calculates the appropriate motor speed (ie, stroke rate) using the syringe and fluid delivery system dimensions.

The microprocessor 63 tracks the position of the platforms 14, 33 by counting the steps performed by the motor 30. Alternatively or additionally, other sensors may also be used to determine and confirm the position of the platforms, such as multiple positions of the platform 33 in its path. In a more preferred embodiment of the invention, there is at least one sensor 72 which detects the end position of the platform 33. All other positions of the platform 33 are calculated from this end position. For example, the end position could be the left end position shown in Figs. 4.

The motor 30 is typically made with rare earth permanent magnets, so it can be relatively compact and still generate high torque.

Returning to FIG. 11, in step 83, the microprocessor 62 sends a command for the microprocessor 63 to push the platform 33 to its end position. This type of list of all commands is stored in memory 64 as part of the control mechanism database. Microprocessor 63 holds the motor on until platform 33 reaches its end position, this position is changed by output from sensor 72 and communicated to microprocessor 62. Next, in step 88, microprocessor 62 orders

V _t platform 33 to its original position. This initial position is a function of the syringe selected and the amount of fluid in the syringe and is set by a template memorized in the template database.

System 1 is now ready to receive the pre-filled syringe. FIG. 13 shows a typical view of the display 66 which may be shown to the practitioner at this time. This screen has several step-by-step or programmed "buttons" that can be activated by the practitioner to initiate certain commands, as well as uncover several areas containing information for the practitioner. In this particular case, the display shows the following buttons 89, named: Quit, Print, 'Feet. Other times, other buttons may be displayed.

In addition, FIG. The display has the following information zones: message zone 90, which contains instructions for the next phase; or a message is displayed informing the practitioner of the current step or processes; two charts 91,

92, showing fluid flow and outlet pressure as a function of time, syringe symbol 93, pressure transducer 94 representing current outlet pressure as a percentage of maximum possible pressure (another parameter formed as part of the template), another transducer assembly generally designated 95 and showing these parameters : platform 33 position (and thus piston position in cylinder) inches from baseline, volume of fluid injected (or biopsied), current flow rate, cm³/ s, current pressure, pounds / m², the force applied and the force applied to the pedal switch 74. At the beginning of step 88, the display areas 90, 91, 94, and 95 indicate zero values ​​for the respective values, and the symbol 93 has a reference 96 indicating that the syringe has not been detected. Display area 90 shows a message instructing the practitioner to insert syringe 6 and press the pedal 74.

The practitioner can now take the pre-filled syringe and insert it into the groove 17 with the finger loop 42 inserted into the opening 19 and the finger support 44 inserted into the opening 28 of the platform 14. This initial position is defined as the position in which the pre-filled syringe 6 can be mounted with its finger rest 44 inserted into the opening 28. It should be noted that the system does not accept syringes in any other position. The software is used to ensure that the correct syringe is filled with the correct amount of liquid and that the other syringe cannot be mistakenly filled.

The system is waiting for step 97 to install the syringe. The physician-practitioner may determine that the syringe is mounted either by physically activating the footswitch 74 or by actuating the pedal button 89 on the display. Once the pedal signal is captured, medication can begin to flow. The first red stop symbol 96 is deactivated. If the practitioner requested cleansing, in step 98, the system is checked. If so, cleaning is performed in step 99, whereby the drug delivery system is freed from possible air bubbles. The volume of needle, handle, and tube is known, and therefore the volume of fluid to be cleaned is easily calculated.

As mentioned above, it is preferable that the foot switch 74 has an air bellows and an air pressure sensor (not shown). The air pressure sensor output is fed to an analog-to-digital converter 75 and the foot sensor output digital equivalent is fed to a microprocessor 63. The microprocessor 63 utilizes the sensors in conjunction with an information lookup table stored in erasable programmable memory 86 to determine or generate a switch position indication. It is found that for best response and maximum sensitivity, the switch position is converted to four different positions or statuses using hysteresis. In other words, as shown in Figs. 14, initially the switch is in the off position. When the switch is depressed, its internal pressure increases. When it reaches the first meaning

ON1, microprocessor 63 generates a LOW FLOW command. If the pressure increases but does not exceed ON2 then the LOW FLOW command is maintained. If the pressure drops below the OFF1 level, a dead position is detected. Normally the pressure OFF1 is lower than ON1. If the pressure is higher than ON2 then the HIGH FLOW command is generated. This HIGH FLOW command is not deactivated until the pressure drops below the pressure level OFF2, which is lower than ON2.

Returning to FIG. 11, if necessary after cleaning, determines the position or status of pedal 74 in step 100. If the LOW FLOW command is received, then the drugs are distributed at low flow rates. If the HIGH FLOW command is received, drugs are distributed at high flow rates. True meanings to teams

LOW FLOW and HIGH FLOW are set earlier as discussed above.

When the pedal is depressed, the engine is activated and rotates at a predetermined speed corresponding to the required flow rate (step 101). A typical drug delivery is shown in Figs. 15A and FIG. 15B, as it appears in zones 91 and 92, respectively. As can be seen from these graphs, the flow rate increases relatively rapidly to the first value of LOW at To, and directly to a constant level. The outlet pressure begins to rise in a somewhat irregular fashion, defined by the resistance of the fabric to fluid flow and other factors. At Tl, the pedal is activated to a higher level, and the fluid flow rate rises to a new speed. The outlet pressure also continues to rise. At T2, the pedal can be returned to a lower level LOW. As this process continues, the microprocessor 62 continues to control various pressure parameters (step 102), and accumulates the total dispensed volume and compares this volume with the total volume required (step 103). If it is not available, then in step 104, control is performed to determine if pedal 74 is still depressed. If so, step 100 is repeated. If not, then it is concluded that a suction is required and the suction mode is performed accordingly as described below with reference to FIG. 17th

In step 102, the current pressure set by the load cell is controlled to a threshold which is the peak pressure when the system is still safe. This pressure level depends on the components selected for the system. In addition, in step 102, the outlet pressure level is also controlled. As discussed above, fluid pressure at injection has been found to play an important role in the patient's pain and tissue damage during injection. However, if the pressure rises above a certain level, the pain increases dramatically. Thus, the present invention attaches great importance to flow rate control in a manner that provides a low level of outlet pressure.

Specifically, in step 102, if the pressure (i.e., system pressure 5 or outlet pressure) is found to be excessive, then in step 105, the flow rate is reduced. In step 106, the pressure is again controlled. If the pressure is still too high, the flow rate is reduced again in step 105. If the pressure is acceptable, the flow rate is resumed in step 107 and the process continues from step 103.

The flow rate and various other parameters are shown on the display to the practitioner 10 (Fig. 13) so that he can easily see what is going on. Probably the increase in pressure as shown in Figs. 16A and Figs. 16B in TX is caused either by blockage or when the needle reaches the bone. When an abnormal pressure is detected, a visual signal is given, also visually. Therefore, a physician practitioner is required to try to avoid high pressure. However, as the blockade continues and the pressure rises, the flow rate gradually decreases as seen in Figs. 16A until it stops completely.

Returns to step 103 when the required volume is reached, or if the practitioner activates the stop command, step 108 executes the end of the subroutine. During this subroutine, further movement of the syringe plunger is stopped and a message is given to the practitioner to remove the needle. The practitioner may remove the needle, disconnect tube 3 from syringe 6 and discard tube 3, handle 4 v

and needle 5. The suction subroutine discussed below is performed to ensure that fluid from needle 5 does not overflow.

In most cases, suction is required during drug infusion. For example, for infusion of anesthetics after needle insertion, suction requires monitoring of needle placement in the blood vessel. In this case, the suction causes some blood leakage from the blood vessels. This blood becomes visible in knob 4 or needle 5 hub.

As can be seen in Figs. 11, if the pedal is released in step 104, the ASPIRATE mode is initiated as shown in FIG. 17th

More specifically, step 109 performs a control to determine whether the piston 7 in the syringe 30 is stopped. If not, then step 110 controls to determine if the piston is moving at low speed. If so, then step 111 executes low speed braking mode to slow down and stop the engine. Alternatively, step 112 executes a high-speed stop mode to slow down and stop the engine.

Step 113 performs a control to determine if the suction execution 5 is sufficiently clear. Referring to FIG. 3, at the moment the suction command is received, the plunger 7 should be in the extreme right position so that it does not fall out while still pulling it out of the syringe. It is clear that such an event is undesirable. Therefore, in step 113, a control is performed to determine the position of the plunger and the length of the syringe to ensure that it is safe to perform suction without causing the plunger to fall out. If not, then the process stops and in step 114 an error message is displayed to the practitioner indicating that it is not safe to pump at this time.

Alternatively, in step 115, the motor is reversed and rotates in the opposite direction for a predetermined time, forcing the piston 7 to retract. When the piston has traveled a predetermined distance, it stops (step 116). The piston then moves again (step 117) until it returns to its original position in step 113. The engine is then stopped (step 118).

v

Steps 117 and 118 may be omitted if suction is performed at the end of the process as the needle is removed from the tissue.

As such, this system is used to deliver anesthetic to a particular procedure.

For example, if the procedure is periodontal ligature, then the following parameters are required:

Syringe Type: Syringe Size: Medication:

Specific drug weight

Inner diameter of tube:

Pipe Length: Needle Type:

Needle length:

toothed core

1.8 cm³ local anesthetic (Lidocaine HCI 2% and adrenaline 1: 100,000)

0,0361

0.015 in. 60 in. BD 30G y₂0.5 inches

Needle Inside 0.006 Inches Diameter:

Bottom speed: 0.0059 cm³/ s

Top speed: 0.370 cm³/ s

Pressure peak: 250 psi.

It has been observed that when using a normal syringe and needle of the above defined parameters to manually inject the same fluid, an output pressure of up to 660 psi or more is generated.

Other procedures include different syringes, drugs, tubes and / or needles.

As discussed earlier, the critical parameters controlled by the object system are the fluid outlet pressure at the needle tip, that is, the pressure in the tissue when the fluid exits the needle. This is the pressure given by the curves in Figs. 15A and FIG. 16A. However, this pressure is very difficult to measure directly. Therefore, the present invention provides indirect measurement rather than direct measurement. Specifically, the required outlet or needle pressure Pn is obtained from the force indicated by the chamber 34 and the physical characteristics of the system. Specifically, it is found that the outlet pressure during steady state (i.e., when the piston is moving at a constant speed) can be expressed as:

Pn = Ps - dVhn + dVhl - d (Fl + Ft + Fn) where Ps is the pressure generated at the junction of the piston and the liquid as the piston moves;

Vhn - rapid pressure on the needle;

Vhl - rapid pressure in the syringe; d - specific gravity of the fluid;

Fl, Ft and Fn are the losses due to flow friction in the syringe, tube and needle, respectively.

Other small pressure losses in the system have been found to be less than 1% and can be ignored here.

Friction losses are determined empirically and memorized as part of the template for each system element. For example, typical values ​​for Fl, Ft and Fn were found to be:

Fl = 0.1%; Ft = 89%; Fn = 11% of the total basic loss.

The density of the liquid is known and is generally similar to the density of water.

The accelerated pressures are calculated using the expression:

Vhl = a * Q² d / [(n / 4)² D⁴ (2g) j where a is the Reynolds number kinetic energy coefficient, the laminar flux is equal to 2;

Q is the corresponding fluid flow as in Figs. 15A and FIG. 16A; g is the gravitational constant;

D is the inside diameter of the element in question, ie the syringe for accelerated pressure Vhl and the needle for accelerated pressure Vhn.

An additional factor for acceleration must be added as the engine speed increases or decreases. This coefficient is given by the expression:

Ms * a / As + Mt * a / At + Mn * a / An, where Ms, Mt and Mn are the masses of the liquid in the syringe, tube and needle, respectively, and As, At and An are the respective slice areas.

An output pressure setting program (provided in the program list as "Needle Pressure") is added at the end of this description. As can be seen from this list and from the flow curve in Figs. 20, the first friction loss for each of the three components (syringe, tube, and needle) is calculated as follows to calculate the outlet pressure. In step 119, Reynolds number is determined by flow rate, component diameter, and viscosity. If Reynolds number is above 2000 (when turbulent flow is detected) then kinetic energy coefficient (step 120) is set to 1 and friction loss is calculated using Reynolds number (step 121).

For R <2000, (step 122), the kinetic energy factor is set to 2, another expression (step 122) is used to determine the loss due to friction (based on fluid viscosity, flow rate, and component diameter). In the absence of flow, both the friction loss and the kinetic energy coefficient are set to 0 (step 123). Next, when all the parameters of the components are calculated, the flow loss for each component is calculated, the clamping force is calculated, all of these parameters are used to obtain the outlet or needle pressure (step 124).

At all times, the microprocessor 62 checks the pressure (step 102 in Fig. 11), actually calculates the outlet or needle pressure Pn as described previously. FIG. 16B and FIG.

17B shows normal and abnormal pressure curves using these expressions, respectively.

Returning to Step 82 FIG. 11, if the device is to be used to fill the syringe, a filling subroutine is started as shown in FIG. 18. In step 125 FIG. The platform 14 is reset 14. Step 126 performs a test to determine if the syringe is filled with air or without air. If air filling occurs, in step 127, the platform moves the syringe head to the position when the syringe is completely filled. In step 128, the system waits for the syringe to be inserted.

The system must be connected to a source of fluid, such as a vial or bottle, to fill the syringe. Specifically, as shown in Figs. The valve 119 is used to connect the system to the fluid source 120 through the tube 122. To fill the syringe, the valve is disposed so that the fluid source 120 is connected to the syringe. FIG. 19th the fluid source 120 is shown inverted as it has an air cavity 122. For filling with air, the syringe plunger 7 is positioned as if the syringe is full, i.e., FIG. 19 in the position shown. For filling without air, the plunger is pushed in as close as possible to the opposite end, as shown in position 7A. When FIG. 19, the practitioner may insert the syringe into the groove 18 and connect it to the clamp 20 with the plunger head connected to the platform 14.

Returning to FIG. 18, now in step 128 the syringe is detected. In the step

129 the syringe is pushed forward into the emptying position by displacing air from the syringe to the source 120, thereby increasing the pressure therein. In step 130, the position is restored to the initial position with respect to the volume of fluid injected as previously determined by the physician. In step 131, the practitioner is reminded to turn valve 119 to connect syringe 6 to tube 3. The system now returns to step 132.

If step 126 determines that airless filling should occur, then step 127 pushes the platform 14 to the syringe emptying position. The system then waits for the syringe to be positioned in step 133, after which the system proceeds to step 130 as shown.

The system is described to the extent that it performs the injection process. However, it will be apparent to one skilled in the art that it may be used for the purpose of performing an effective biopsy such as spinal puncture or other similar anaerobic procedures. For this process, basically the same parameters can be used with minor adjustments. For example, instead of determining the outlet pressure, the practitioner will determine the inlet pressure. Some subroutines, such as cleaning, filling, or suction, are completely unnecessary for biopsy.

It will be appreciated that many changes can be made to the present invention without departing from the scope of the appended definition.

Program printout

Mathematical Application of the System 5 Example

T Pressure - Record

<td>Flow rate: total;</td><td>// Cubic inches / second (Input)</td>

<td>Mechanism force: general;</td><td>// Inches (DB)</td>

<td>(Machine resistance ???)</td><td></td>

<td>Load cell force: total;</td><td>// Inches (Input)</td>

<td>Syringe force: total;</td><td>// Inches (DB)</td>

<td>Syringe Diameter: Overall;</td><td>// Inches (Input)</td>

<td>Syringe length: total;</td><td>// Inches (DB)</td>

<td>Diameter of pipe: total;</td><td>// Inches (DB)</td>

<td>Pipeline Length: Total;</td><td>// Inches (DB)</td>

<td>Needle diameter: common;</td><td>H inches (DB)</td>

<td>Needle length: total;</td><td>//// Inches (DB)</td>

<td>Specific weight: total;</td><td>// Skewer / cubic inch (DB)</td>

<td>Viscosity: general;</td><td>// Units (DB)</td>

The term DB indicates that the parameter value is selected from one of the databases.

Input - means that the parameter was calculated previously.

Calculated - The value is calculated in this mode.

The end.

Other changes are determined during the process:

End Speed: Overall;

End time: double;

Implementation of function Calculate pressure (P: T Pressure): total; const

Kinetic energy factor = 2.0;

Gravity force = 386.4;

option

Kinetic energy factor for syringe: total;

Kinetic energy factor for needles: total;

Kinetic energy coefficient for pipeline: total; Syringe Friction Loss: Common;

Syringe flow loss: total;

Syringe rapid pressure: total;

Needle Friction Loss: Common;

Needle Flow Loss: Common;

Needle rapid pressure: total;

Pipeline Friction Losses: Common;

Pipeline Flow Losses: Common;

Speed ​​constant: total;

Braking force: total;

Reynolds number in syringe: total;

Reynolds Number in Pipeline: Total;

Reynolds number on needle: total;

Needle pressure: total; // Declared value

Volume, acceleration: total;

Speed ​​Now: Overall;

Time Now: Double;

to get started

Speed ​​constant: = P. specific weight / (area (PI / 4.0) * 2.0 * gravity test

Reynolds number in syringe: = P. flow rate / (PI * P. syringe diameter * (P. viscosity / 4));

if Reynolds number in syringe&gt; = 2000.0, then start Kinetic energy factor for syringe: = 1.0;

Syringe friction loss: = 0.25 / area (log10 (0.0000012 / (3.7 * P. 10 syringe diameter) + (5.74 / force (Reynolds number per syringe, 0.9)))); the end, otherwise the beginning

Kinetic energy factor for syringe: = 2.0;

Syringe friction loss: = (16 * P. viscosity * PI * P. syringe diameter 15) /

P. flow rate end;

to confirm

Syringe friction loss: = 0;

Kinetic energy factor for syringe: = 0;

the end;

to try

Reynolds Number in Pipeline: = P. Flow Rate / (PI * P. Diameter 25 * (P. Viscosity / 4));

if Reynolds number in pipeline&gt; = 2000.0 then start Kinetic energy coefficient for pipeline: = 1.0;

Pipeline Friction Loss: = 0.25 / area (log10 (0.0000012 / (3.7 * P. pipeline diameter) + (5.74 / force (Reynolds number in pipeline, 0.9))));

the end, otherwise the beginning

Kinetic energy coefficient for pipeline: = 2.0;

Pipeline Friction Loss: = (16 * P viscosity * PI * Pipe Diameter) /

P.flow speed end; to confirm

Pipeline friction loss: = 0;

Kinetic energy coefficient for pipeline: = 0;

the end;

to try

Reynolds number per needle: = P. flow rate / (PI * P. needle diameter * (P. viscosity / 4));

if Reynolds number on the needle:&gt; = 2000.0 then start

Kinetic Energy Ratio for Needles: = 1.0;

Needle friction loss: = 0.25 / area (log10 (0.0000012 / (3.7 * P. needle diameter) + (5.74 / force (Reynolds number on the needle, 0.9))));

the end, otherwise the beginning

Kinetic Energy Ratio for Needles: = 2.0;

Needle Friction Loss: = (16 * P. viscosity * PI * P. needle diameter) /

P. flow rate end;

to confirm

Needle friction loss: = 0;

Kinetic energy factor for needles: - 0;

the end;

Volume: = ((PI / 4) * area (P. syringe diameter) * P. syringe length) + ((PI / 4) * area (P. pipeline diameter) * P. pipeline length) + ((PI / 4 ) * area (P. needle diameter) * P. needle length)

Speed ​​now: = P. flow rate / ((PI / 4) * area (P. syringe diameter));

Current time: = now * 24 * 60 * 60;

if (time duration&gt; 0) and (not P. test mode) then start Initial Power On

Acceleration: = ((P. Specific Weight * Volume) / Gravity) * // ABS ???

((End speed - Current speed) / Current time Time duration));

end, otherwise start Acceleration: = 0;

the end;

End speed: = Current speed; // save for next time Current time: = Time duration;

Needle Rapid Pressure: = (Velocity constant * Kinetic energy factor for needles) * (Area (P. Flow rate) t

Force (P. Needle diameter, 4.0));

Syringe Rapid Pressure: = (Speed ​​constant * Kinetic energy factor for syringe) * (Area (P. Flow rate) /

Force (P. Syringe diameter, 4.0));

Syringe Flow Loss: = (Syringe Friction Loss * P. Syringe Length * Area (P. Flow Rate)) / (P. Syringe Diameter * 2.0 * Gravity Force * Area (PI * Area (P. Syringe Diameter) / 4 , 0));

Pipeline Flow Loss: = (Pipeline Friction Loss * P. Pipeline Length * Area (P. Flow Rate)) / (P. Pipeline Diameter * 2.0 * Gravity Force * Area (PI * Area (P. Pipeline Diameter) / 4 , 0));

Needle Flow Loss: = (Needle Friction Loss * P. Needle Length * Area (P. Flow Rate)) / (P. Needle Diameter * 2.0 * Gravity Force * Area (PI * Area (P. Needle Diameter) / 4 , 0));

Braking force: = P. Load cell force - P. Syringe force - P. Mechanism force;

// Braking force: = P. Load cell force;

Needle pressure: = (Braking force / (PI * area (P. Syringe diameter / 2)) Fast needle pressure + Syringe fast pressure (P. Specific gravity * (Syringe flow loss + Tubular flow loss + Needle flow loss) 20 (Acceleration) / (PI * area (P.Syringe diameter / 2))));

the end.