Infusion fluid heat exchanger and cartridge

p00001Infusion fluid heat exchanger and corresponding cartridge

5 Background of the invention

p00002Field of the Invention

p00003The present invention is directed to a heating fluid for infusion in the body of a patient without damaging the fluid through exposure to temperature rise as well as preventing the introduction of air into the patient's body.

Background

p00004fifteen The fluid required in the treatment of a patient must often be stored cold at relatively cold temperatures with respect to the patient's body temperature. This refrigerated storage is often necessary to preserve the fluids in a state so that the function and integrity of the fluid is maintained. Fluids such as blood and other body fluids are usually stored at hypodermic temperatures ranging from 2 ° to 20 ° Celsius. Therefore, when fluids are introduced into the patient's body it is often necessary to heat the fluid to a suitable temperature not only to avoid any rapid decrease in the patient's body temperature, but also to ensure that the fluid being introduced can Run as necessary. It is known that the injection of cold fluids into a patient's body can create an important source of heat loss by conduction within the patient, often putting the patient at additional risk by cooling, too quickly or, at a temperature at that physiological damage can occur.

p0000525 However, during heating or when the temperature of the liquid increases, care must be taken to ensure that the heating itself does not create an additional complication. For example, if the blood is exposed to a temperature above 45º Celsius, severe hemolysis, destruction or degradation of blood cells can occur. Likewise, if the fluid gets too hot and is then introduced into the patient's body, physiological damage resulting from exposure to excessive temperatures, such as burns or other scars, can occur. The heating of the fluid by volume generally requires an application of too intense a heat source to heat all the fluid with any level of time efficiency. Similarly, heating the fluid for a prolonged period of time can lead to greater exposure of the material to the environment creating risks of contamination.

p0000635 Introducing the fluid into the patient requires an adjustable flow so that the appropriate amount of fluid depending on the need is supplied to the patient. Combining the fluid delivery medium with adequate and effective heating of the fluid is crucial for the correct supply of fluid to the patient. The prior art contains fluid systems for heating as they are infused into a patient. The way in which fluids heat up within these systems varies and can be carried out through convection or conduction. An example of a system that raises clinical problems heats the fluid that is being supplied to the patient through exposure to a hot fluid, such as water. Such systems are often complicated, require frequent cleaning, and can contaminate the clinical environment by introducing an additional substance - the heating fluid. Such a system often places a conduit through

p00007Four. Five of a liquid such as water, which is then heated, and the fluid that has to be supplied to the patient is extracted through the conduit thereby increasing the temperature of the fluid to be supplied. Such a system can be detrimental to a sterile environment and cannot be transported properly. On the other hand, these systems also have a large mass that requires significant power to heat that mass reaching a significant time to reach that temperature, or reach an ecstasy when a cold mass (such as a cold fluid bag) is introduced.

p00008In addition, during some fluid infusion procedures it is beneficial to adjust the temperature of the patient's body, either by heating or cooling it. As such, it is extremely beneficial to have an adjustable in-line fluid heating system so that the proper temperature can be regulated. In the cases

p0000955 of massive or emergent loss of fluid, it is often necessary to infuse extremely large amounts of fluid into the patient's body. In such cases, traditional fluid heating systems often put the fluid at risk from exposure to temperatures that could damage the fluid because the fluid must be heated very quickly. Such problems remain largely unresolved by the technique and the need for better in-line fluid infusers is abundant.

p00010When fluid is introduced into a patient's body it is crucial that no air is introduced into the patient's body. The introduction of air or air bubbles into a patient's body can have very harmful effects. Air embolisms can occur if air accumulates in a patient's bloodstream, resulting in cardiac arrhythmias, strokes, or pulmonary infarctions. Any of these

p0001165 Potential diseases can be life threatening and situations in which large volumes of body fluids are being infused need to be minimized. Therefore, it is extremely important that during the infusion of body fluids that both the air in the infusion system is controlled and that its introduction into the patient's body is avoided.

p00012Prior art devices that attempt to heat the fluid by infusion into the body often suffer from 5 very specific problems. For example, the heating system described in US Patent No.

p000133,590,215 issued to Anderson et al. It uses different regions of heat than the fluid is found as it progresses through the system. Specifically, the heating element or elements described in Anderson et al. the heat in the material that heats the fluid from a higher temperature decreases, at which the fluid enters the heat exchanger to a lower temperature, at which the fluid leaves the heat exchanger.

p0001410 Such a configuration not only makes it difficult to regulate the temperature of the fluid as the flow rate changes, but also runs the risk of having to expose the fluid to temperatures above which the fluid should be exposed, taking the risk of damaging the fluid.

p00015Similarly, the meandering fluid flow path described in Anderson et al. create the typical type flow

p00016fifteen Laminar observed in most heat exchanger systems. For example, U.S. Patent No. 5,245,693 to Ford et al. It describes a meandering flow pattern that is long compared to its width and wider compared to its depth. This type of flow is consistent with a non-turbulent laminar flow path. A non-turbulent flow path requires additional thermal energy to enter the fluid system to increase the temperature of the fluid system evenly until

p00017twenty a desired temperature

p00018US 2005/008354 A1 describes a disposable fluid infusion cartridge according to the preamble of claim 1, that is, it comprises a heat exchanger comprising the first and second faces of an interior heat exchange zone defined by a first and second pluralities of 25 superimposed fins, creating a deep trajectory of substantially uniform tortuous flow, in which each fin has a height ratio with respect to the width of at least 1: 2, whereby the fluid enters the second face of the heat exchanger by means of a first access and loads a first flow cavity to through the width of the heat exchange zone before at least partially flowing through the width of each subsequent superimposed fin and through the heat exchange zone and outside the second access in the

p0001930 First face of heat exchanger.

p00020US 4707587 A illustrates and describes the exact winding path shape exhibiting non-turbulent laminar flow characteristics, which requires a heat increase to adequately heat the fluid.

p0002135 In US 5591251 A, an air trap shown in Figure 3 has a wedge-shaped baffle that projects inwardly from the middle portion of the air trap, which functions to divert incoming fluid to a chamber upper and lower chamber separately, after which gravity causes the blood to flow down and mix. The blood flowing down in the lower chamber is directed towards your

p0002240 middle section to further allow it to mix with the blood flowing from the upper chamber. After mixing, gravity continues to force the blood to pass from the lower chamber through the perforations in a filter and out of the exit port, which is illustrated by positioning itself centrally.

p00023US 6464666 B1 describes a very simple bubble trap that has a tube connected to the access

p00024Four. Five output 40 of the container, a bubble trap 50 and an outlet 54 connected to the patient. A gas exhaust port vents the gases that escape the communicated fluid.

Summary of the invention

p00025fifty The present invention provides disposable fluid infusion cartridge according to claim 1. The disposable cartridge according to the present invention will allow an efficient transfer of thermal energy to the fluid being administered by infusion into the patient's body. The cartridge will also ensure that harmful amounts of air are not introduced into the patient's body.

p0002655 The embodiment provides a system for increasing the temperature of a fluid that is infused into a patient's body while the infusion is being performed. A heating system of this type is also known as an in-line heating infusion system. The embodiment also provides better air control in the infusion system such as to prevent the introduction of air into the body of the patient receiving the infusion of fluids. The embodiment also provides a system pump that provides a variable flow rate.

p0002760 It serves a lot of needs and purposes of infusion.

Brief description of the drawings

p00028Figure 1 is an elevational view of the internal elements of a disposable cartridge according to the present invention.

p00029Figure 2a shows a different orientation of the disposable cartridge according to the present invention (proximal lid of the disposable removed).

p00030Figure 2b shows the disposable cartridge side of an embodiment of the present invention that abuts 5 with the pump housing.

p00031Figure 2c shows the pump housing with an exposed stage representing a face of the present invention.

p00032Figure 3 shows a half of the heat exchanger - a plurality of fins.

p00033Figure 4 is a cross-section of the artificially recessed heat exchanger, showing a fluid flow path according to an embodiment of the present invention.

p00034fifteen Figure 5 is an exterior view of an air trap comprised in the cartridge of the present invention.

p00035Figure 6 is a cross section of an air trap comprised in the cartridge of the present invention.

p00036Figure 7 shows the shape of the fluid that a heat exchanger could charge in accordance with the present invention.

p00037Figure 8 shows a disposable cartridge of an embodiment of the present invention.

Detailed description of the invention

p0003825 The present invention contemplates a disposable heat exchange cartridge for use in the infusion of fluids into a patient's body. The disposable heat exchange cartridge is coupled so that it can be separated to an infusion pump device that provides not only the energy or power necessary to transport heat to the fluid being infused, but also provides the generation pump. flow and mechanisms for the supervision and regulation of certain aspects of the fluid infusion system. In this description of the invention reference will be made to the embodiments shown in Figures 1-8 in which the same reference numbers are used to designate equal parts in all drawings. Figures 1 and 2a-c describe a presently preferred embodiment of the present invention and should not be construed as limiting.

p0003935 An embodiment of the present invention is a disposable fluid infusion cartridge comprising a heat exchanger having upper and lower faces and an interior heat exchange zone defined by a first and second plurality of overlapping fins, creating a path depth. of substantially uniform flow, in which each fin has a height ratio to the width of at least 1: 2, whereby the fluid enters the lower face of the heat exchanger through a lower access and loads a lower flow cavity through the width of the heat exchange zone before flowing through the heat exchange zone heat and outside an upper access on the upper face of the heat exchanger.

p00040The disposable fluid infusion cartridge may further comprise an air trap that has upper and lower faces, an inner surface, which receives the fluid from the heat exchanger, and which further comprises a

p00041Four. Five fluid flow disruptor and a purge mechanism to purge air from the air trap and prevent air from passing beyond the air trap. The disposable cartridge of this embodiment may have a ratio of the height of the fins to the width of the fins from about 1: 2 to 1:50, preferably from about 1: 4 to 1:25, and more preferably from about 1: 5 to 1:10. The height of the fins in the present embodiment may be from about 6.35 mm (0.25 inches) to about 25.4 mm (1 inch).

p00042The disposable cartridge of the present embodiment may have a ratio of the flow path depth to the fin height of about 0.01 to about 1: 1. The flow path of the heat exchange zone of the present embodiment may have a depth of approximately 0.25 mm

p0004355 (1 inch) to approximately 6.35 mm (0.25 inches). In addition, the distance between a first and second fins within the same plurality of fins may be from about 6.35 mm (0.25 inches) to about 12.7 mm (0.5 inches). In addition, the heat exchanger of the present invention may be composed of two symmetrical units fixed to each other, a single unit, or be composed of at least two units fixed to each other.

p00044The air trap of the present embodiment of a disposable fluid infusion system may be cylindrical, in which the air trap is taller than wide. The air trap of the present embodiment further comprises a fluid flow disruptor that extends from the inner surface of the bottom face of the air trap. In addition, the purge mechanism can use an ultrasonic detection mechanism to control the volume of fluid in the air trap. Similarly, the purge mechanism of the present embodiment can use a valve in a fluid outlet port and a valve in a tandem air outlet access for

p00045force the air out of the air outlet access as the volume of the fluid inside the air trap increases to a predetermined level. The air trap of the present embodiment can effectively remove the air when it moves out of its vertical axis up to 45 °.

p000465 In accordance with the present invention, the disposable infusion cartridge may comprise a heat exchanger comprising a closed path of uniform tortuous flow containing short segments of linear flow length, creating a fluid tape, greater in width than the length of the segments of the flow length, uniform, for improved exposure to the inner surface of the heat exchanger and the mixing of the fluid through non-laminar flow to improve thermal transfer within the fluid. The disposable infusion cartridge of this embodiment may further comprise a cylindrical air trap to remove air from the disposable cartridge comprising an upper and lower face and further comprising a fluid inlet port, a fluid outlet port, a port air outlet, and a fluid flow disruptor, wherein the air trap creates a fluid vortex and the fluid flow disruptor creates a pressure differential in the fluid outlet access to extract the fluid from the air trap.

p00047fifteen The cartridge of this embodiment may have a ratio of the length of the short segments of the tortuous flow path to the width of the flow path of about 1: 2 to 1:50, preferably about 1: 4 to 1 : 25, and more preferably from about 1: 5 to 1:10. In this embodiment, the length of the short segments of the tortuous path may be from about 6.35 mm (0.25 inches) to about 25.4 mm (1 inch) in length. Similarly, the depth of the tortuous flow path has a depth relationship with respect to the length of the short flow length segments of approximately 0.01 to 1: 1, with a specific depth of approximately 0.25 mm ( 0.01 inch) to approximately 6.35 mm (0.25 inches).

p0004825 The heat exchanger of the present invention can create the tortuous path through at least a plurality of fins. Within the plurality of fins, the distance between a first and second fin can be from about 6.35 mm (0.25 inches) to about 12.7 mm (0.5 inches).

p00049The fluid flow disruptor of the air trap of the current embodiment may extend from the inner surface of the air trap. In addition, the purge mechanism can use an ultrasonic detection mechanism to control fluid height. Similarly, the purge mechanism can use a valve in a fluid outlet port and a valve in a tandem air outlet port to force air out of the air outlet port as the volume increases of the fluid inside the air trap. In addition, the purge mechanism valves can be controlled by the control mechanisms contained within a

p0005035 Pump housing reversibly attachable to the cartridge.

p00051In a further embodiment of the present infusion cartridge, the device may comprise at least one pressure monitor to control the fluid pressure inside the disposable cartridge, as well as a bubble detector to control the presence of bubbles within fluid that is passed through the disposable cartridge.

p00052The heat exchanger 101, as depicted in Figure 1, is contained within the disposable cartridge.

p00053100 The disposable cartridge is attached so that it can be separated to the pump system such that once the treatment is completed, the disposable cartridge can be removed and discarded. The disposable cartridge is autonomous and once connected to the pump system does not need to be adjusted or manipulated. The fluid enters the

p00054Four. Five disposable cartridge in the primary inlet tube 102 that draws fluid from the fluid source. The fluid is introduced into the primary inlet tube 102 and proceeds beyond a first T-junction that serves as the incoming flow pressure monitor 103. The incoming flow pressure monitor 103 is in fluid communication with a first chamber of air 151. The incoming flow pressure monitor 103 determines the fluid flow pressure as it enters the pump loop 104 to allow adequate fluid flow regulation. The pump loop 104 interacts with a rolling or otherwise removable pressure system. The pump loop 104 in its interaction with a pumping system pushes the fluid through the disposable cartridge 100. When the fluid exits the pump loop 104 it flows through a second T-junction that serves as the outgoing flow pressure monitor 105. The outgoing flow pressure monitor 105 determines the fluid pressure as it exits the loop. of the pump 104 so that the flow of the fluid through the disposable cartridge 100 can be regulated.

p0005555 The fluid is then passed to the heat exchanger 101 through the inlet port of the exchanger 106 on the bottom face of the heat exchanger. After the fluid has been passed through the turbulent medium established by the heat exchanger 101, it exits through the outlet access of the exchanger 107 which is located a position opposite the inlet access of the exchanger 106 on the upper face of heat exchanger 101. At this point, the infusion fluid has withstood its heating and the desired temperature has been reached.

p00056The fluid exits the heat exchanger 101 through the outlet access of the exchanger 107 and then enters the air trap 110 at approximately the midpoint along the longitudinal axis of the air trap 110.

p0005765 The fluid flows out of the air trap 110 and through a third t-junction that serves as an out-of-flow bubble detector 112. The out-of-flow bubble detector 112 determines whether excess amounts of air have infiltrated the system. If an unacceptable level of air remains in the fluid as it flows past the bubble detector out of flow 112, the system will not allow infusion of that fluid into the patient's body. If the fluid does not contain air, or a minimum amount of air that is acceptable, the fluid is passed to the bubble detector out of the flow and to the patient through the primary outlet tube 111.

p000585 A detailed description of the heat exchanger 101 requires reference to Figures 3 and 4. The heat exchanger 101 can be created by two halves molded from the same mold each containing a plurality of fins. A first half 301 is composed of the inlet access of the exchanger 106 and a plurality of fins comprising a series of spaced fins 302. With the exception of a specially sized flow fin 303, each of the fins 302 have the same size and are spaced equidistant from each other. As the fluid enters the heat exchanger 101 through the inlet access of the exchanger 106, the fluid fills the flow cavity 304 defined by the inner walls of the heat exchanger and the flow fin 303. When in operation, the heat exchanger is oriented in such a way that a lower face, in which the inlet hole is located, and an upper face, in which the

p00059fifteen orifice, are oriented in a vertical way forcing the fluid to flow in an upward direction through the heat exchanger and against gravitational forces. Due to the special shape given to the flow fin 303, the fluid fills the flow cavity 304 before proceeding through the heat exchanger 101.

p00060Figure 4 is used to describe the flow of fluid through the heat exchanger 101, the fluid enters the flow cavity 304 through the inlet port of the exchanger. Due to the differentially sized flow fin 303, the fluid first fills the flow cavity 304 before rising above the first fin. This preliminary filling allows the fluid to fill the width of the heat exchanger and flows like a wide ribbon of fluid through the fins opposed to a laminar flow through a long but narrow duct. The flow fin 303 performs proper diffusion of fluid by creating a thinner flow vacuum 305 between the fin

p0006125 of flow 303 and the first of the plurality of fins on a regular basis. The fluid then flows to the length of the heat exchanger 101 between the inlet port of the exchanger and the outlet port of the exchanger. As the fluid rises, it travels in a wave like a superficial but wide band of fluid. The short, wide flow linear flow pattern created by the heat exchanger creates a turbulent flow that causes increased molecular circulation within the fluid. While the laminar flow within typical ducts, such as tubes, see higher molecular "turns" in the central portion of the duct, the turbulent flow inside the heat exchanger 101 provides much more exposure of different molecules to the inner surface of the exchanger of heat thus facilitating a more efficient and effective energy transfer.

p00062Returning to Figure 3, the other half of the heat exchanger can be created from the same mold, in which

p0006335 the input of the exchanger 106, becomes the output of the exchanger. Once formed, the two halves are mounted together using means known in the art, including but not limited to, bolts, screws or other mechanical means, as well as glues, cements, or other chemical means. If mechanical means are used, then fixing tabs 306 can be used to house the fixing devices.

p00064Figure 4, the cross-sectional view of the heat exchanger, further shows the seal seat 401 which provides a space for placing a seal around the circumference of the heat exchanger to increase the fluid impermeability of the heat exchanger, such Like an O-ring It should be noted that although the heat exchanger of the present embodiment is described as being formed from two halves

p00065Four. Five identical, the heat exchanger could be formed as a single piece or more than two pieces. To facilitate manufacturing, however, two identical halves as described herein allow for the appropriate result at a lower cost.

p00066The heat exchanger of the present invention can be formed from any number of materials: molten anodized aluminum, copper, gold, and the like. The material chosen for use in the heat exchanger of the present invention must be capable of adequate heat conduction and dispersion to ensure proper distribution of heat across the surface, as well as thermal transfer to the fluid to be heated. . Thermodynamics dictates that for two materials with the same specific heat, which is the amount of thermal energy required to change the temperature of the material of one unit per unit of mass, material 55 with a greater mass will more efficiently transfer heat to the material with a minor mass This level of efficiency is often understood as thermal capacitance - because materials with higher thermal capacitance (i.e. mass) will retain more heat during the transfer of energy to the adjacent material sufficient to significantly increase the temperature of the second material without unwanted loss. of energy By analogy, heat exchange occurs between the heat exchanger and the infusion fluid by way of example, a material with a mass of 1.5 kg is heated to 60 ° C and placed in close and direct contact with a material which has a mass of 0.5 kg at a temperature of 40 ° C. When heating is completed, both materials reach a temperature of 55 ° C. The energy stored by the hottest component through its increase in mass allows a better exchange of thermal energy between the two materials. The selection of a material, taking into account the special needs of the present invention, therefore, requires

p0006765 consideration of the mass of the material, as well as the thermodynamic properties of that material.

p00068Figure 5 shows an enlarged view of the air trap 110 and its connective ducts. Although the air trap is described with reference to specific forms, it should be apparent to one skilled in the art that any form that allows the reversal of the fluid flow direction in the fluid outlet access of the air trap will allow the air tracking and removal of the cartridge system. The air trap is generally shaped

p000695 cylindrical with a vaulted upper part 501 and flattened lower 502. The fluid enters the air trap 110 at the inlet port of the air trap 503 which is located approximately midway along the longitudinal axis of the trap air . The fluid enters the air trap 110 from the heat exchanger in order to remove trapped air or enter the fluid. The air that is removed can come from the lack of purging in the source of air fluid before introducing it into the present invention. It is also possible that the heating of the fluid causes the release of gas from the envelope creating bubbles that if allowed to enter the patient's body could be harmful or even fatal. The fluid exits the air trap 110 through the fluid outlet access 505 which is located at the bottom 502 of the air trap.

p00070Figure 6 represents a cross section of the air trap 110. In this view, the access can be observed

p00071fifteen input of the air trap 503, since it is in the interface with the air trap. The air trap inlet access 503 is smoothed towards the inner wall of the air trap and is positioned outside the midline of the longitudinal axis of the air trap. This position of the entrance of the air trap 503 in relation to the midline of the longitudinal axis of the air trap causes the fluid being introduced into the air trap to flow over the cylindrical shape of the air trap in one direction clockwise as the fluid fills and continues to enter the air trap. This flow pattern creates a vortex in the air trap by pulling the air down, toward the fluid outlet access. At the bottom 502 of the air trap is a flow disruptor 601 that is located adjacent to the fluid outlet access 505. The flow disruptor can be extended from the inner wall of the air trap or from the inner wall of the bottom 502 of the air trap. Since the fluid, which is traveling clockwise over the air trap, flows through the disruptor of

p0007225 flow 601, a pressure differential is created in the fluid outlet port 505 by extracting the fluid from the air trap and allowing air or gas bubbles to flow upward along the longitudinal axis of the air trap.

p00073Returning to Figure 5, the fluid level inside the air trap is continuously monitored while the infusion device is being operated. When the fluid level in the air trap 110 falls below the lower level sensor 506 a valve located at or above the fluid outlet access 505 is closed. At approximately the same time that the valve located at or above the fluid outlet access 505 is closed, a valve located at or above the air outlet access 504 opens. With the fluid outlet access 505 closed, the fluid entering the air trap 110 forces any air present in the air trap to rise along the longitudinal axis 35 of the air trap. Because the air outlet access 504 is open, the air inside the air trap is forced out of the air trap and into the air outlet tube 108 shown in Figure 1. When the fluid level in the air trap 110 rises above the upper level sensor 507, the valve in the air outlet access 504 closes. At approximately the same time that the valve in the air outlet 504 closes, the valve in the fluid outlet 505 opens again. With fluid outlet 505 open, fluid flowing to the patient through the primary outlet tube is restored

p00074111.

p00075The air trap used in the present invention is capable of operating at different inclinations and orientations. The cylinder formed by the air trap is between 76 mm and 254 mm (3 inches and 10 inches) high,

p00076Four. Five preferably between 89 mm and 178 mm (3.5 inches and 7 inches), and more preferably between 102 mm and 152 mm (4 inches and 6 inches). The diameter of the air trap cylinder is between 13 mm and 51 mm (0.5 inches and 2 inches), preferably between 16 mm and 38 mm (0.625 inches and 1.5 inches), and more preferably between 19 mm and 32 mm (0.75 inches and 1.25 inches). The air trap is able to properly remove the air from the fluid as it is passed through it, even when the air trap tilts out of its vertical axis up to 45 °.

p00077As mentioned above, the efficient transfer of heat from the heating element to the heating fluid strongly impacts the present invention. The use of the present invention of a wide, short linear path flow pattern allows a more turbulent flow with a very large contact area. The contact area 55 described is the area of ​​the interface between the heat exchanger and the fluid that is passed through it. Described as a fluid belt, the fluid traveling through a heat exchanger manufactured in accordance with the present invention will flow over very short linear distances along the short linear distance segments, but will be proportionally greater. In fact, the cavity created by the flow of fluid through the heat exchanger is wider than long, and longer than deep, thus creating a form of tortuous tape for the fluid to pass through it. Figure 7 is a representation of the fluid flowing through the heat exchanger 100. The fluid flow of Figure 7 is first shown as having filled the inlet port of the exchanger as an inlet fluid 701. The fluid then fills the flow cavity like the fluid in the cavity 702. Next, the fluid flows to the first heat exchanger through the smaller gap created by the flow fin indicated as the first restricted flow 703. It should be noted that the linear flow distance λ, defined by the height of the fins and represented the short segments of flow length, is smaller than the flow width ω. The relationship between the linear flow distance λ and the width of

p00078flow ω may be about 1: 2 to 1:50, preferably 1: 4 to 1:25, and more preferably 1: 5 to

p000791:10 It is the relationship between the linear flow distance and the flow width that creates the tape-shaped flow pattern depicted in Figure 7. By having a short linear flow, the fluid flows through the heat exchanger with more turbulence. than a typical long meandering path. The introduction of the turbulence in the fluid avoids the flow of the laminar type that a winding flow path of this type can create. Unlike only the molecules within the central portion of the fluid flow, that is, those molecules that are not directed at the interface, changing faster than the molecules at the interface, the turbulent flow created by the present invention exposes more molecules. of fluid in the interface allowing an improved thermal transfer. Similarly, this turbulent flow creates greater contact between the molecules in the fluid that flows through the

p0008010 heat exchanger. With greater contact between the molecules in the fluid, greater heat exchange and transfer can occur leading to the effective exchange of heat from the exchanger to the fluid that has to be supplied to the patient.

p00081A cartridge heat exchanger manufactured in accordance with the present invention creates this flow path.

p00082fifteen turbulent and maintains it as the fluid flows along the fins. The fins, as depicted in Figure 3, create a half of the flow path for the fluid to follow. The fins on the same side of the heat exchanger are equally sized and spaced, that is, the distance between a first fin 307 and a second fin 308 is the same across the entire interval of the heat exchanger. For the purposes of thermal transfer involving a fluid flowing in the heat exchanger, the distance between a first and

p00083twenty second fins of the same plurality of fins may be 6.35 mm to 12.7 mm (0.25 inches to 0.5 inches), preferably 12.7 mm to 20.32 mm (0.35 inches at 0.45 inches), and more preferably from 9.4 mm to 10.9 mm (from 0.37 inches to 0.43 inches). The length of the fins in the middle of the heat exchanger dictates the linear flow distance. The length of the fins may be about 6.35 mm to 25.4 mm (0.25 inches to 1.0 inches), preferably 12.7 mm to 20.32 mm (0.5 inches to 0 , 8 inches), and more

p0008425 preferably from 15.24 mm to 17.8 mm (from 0.6 inches to 0.7 inches). The flow path also contains a depth element created by the separation distance between the upper part of the fins in a first plurality of fins and the valley between two fins in a second plurality of fins. The flow path may have a depth of about 0.25 mm to 6.35 mm (0.01 inches to 0.25 inches), preferably 0.76 mm to 3.17 mm (0.03 inches to 0.125 inches), and more preferably from 1.02 mm to

p0008530 2.70 mm (from 0.04 inches to 0.110 inches). The width of the fins may be 76 mm to 114 mm (3 inches to 6 inches), preferably 89 mm to 127 mm (3.5 inches to 5 inches), and more preferably 101 mm to 114 mm ( 4 inches to 4.5 inches).

p00086The transfer of thermal energy to the heat exchanger occurs in the exposed portion of the exchanger

p0008735 of heat, which is the portion not covered or contained within the disposable cartridge. The flat plate 801 of the heat exchanger is visible in Figure 8 exposed from the housing 802 of the disposable cartridge 100. The disposable cartridge 100 is detachably attached to the pump system through a first fixing region 803 and a second region fixing 804. The fixing regions allow the disposable cartridge to be securely and firmly fixed in the pump system. It is extremely important that the flat plate

p0008840 801 of the heat exchanger is located as close as possible to the heating element or stage. It is equally important and difficult to ensure that the flat plate 801 of the heat exchanger is uniformly close to the heating element or stage. It is even known that with smooth materials, when it comes to solids, they are rarely completely in contact when considered at a microscopic level. Therefore, the flat plate 801 should be as uniform and smooth as possible in order to achieve the greatest

p00089Four. Five possible surface comes into contact with the heating element or stage. The surface area of ​​the flat plate 801 that contacts the heating element or stage can be from about 20 square inches to about 100 square inches, preferably from about 25 square inches to about 50 square inches, and more preferably from about 30 inches square to approximately 45 square inches. Similarly, the pressure exerted on the cartridge

p00090fifty disposable 100 to hold the flat plate 801 in close contact with the heating element or stage should increase if the surface of the flat plate 801 and the heating element or plate are not smooth. If the flat plate 801 and the heating element or stage are placed immediately next to each other, an air interface is considered to exist between the two surfaces. Because while the surfaces are extremely close and the pressure is exerted on the flat plate, to press the two surfaces together 801,

p0009155 the gaps will remain between the surfaces. Therefore, it is possible to reduce these gaps by coating the heating element or stage that contacts the flat plate 801 of the heat exchanger with a thermal pad that adjusts and fills the empty spaces between the surfaces with a material that is a conductor of heat better than air, still allowing reasonable contact pressure to be used. If the air serves as an interface between the surface of the flat plate 801 of the heat exchanger and the element or

p0009260 heating stage, then, the greatest pressure must be exerted on the system in order to achieve an efficient transfer of thermal energy. Using a material that fills the gaps and is a better conductor of heat than air allows the system to be established with a lower and more reasonable pressure applied to the surface interface.

Example

p00093An infusion system under the present invention shown in Figure 2a-c. The disposable cartridge is shown with half of its outer cover removed in Figure 2a. For orientation purposes, the air trap 110 is

p000945 visible extending outside the outer cover 201 in the right portion of the figure. The outer cover of the disposable part is made of resistant polymeric material. Figure 2b shows the side of the disposable cartridge that will come into contact with the pump housing 250 shown in Figure 2c. Again for orientation, the air trap 110 is shown in Figure 2b in the left portion of the figure extending out of the outer cover 201. The exposure surface 225 of the heat exchanger 101, which will come into contact with the pump system stage, is shown in Figure 2b. Figure 2c shows the pump housing containing the roller pump to interact with the pump loop 104. Figure 2c also shows the plate 275 that provides thermal energy to the heat exchanger contained within the disposable cartridge. All the elements of this Example are in fluid connection with each other.

p00095fifteen The coupling handle 280 allows the user to reversibly connect the disposable cartridge 100 to the pump housing 250 by fixing or other locking mechanisms extending from the locking housings 285 located on the plate 275. When the coupling handle 280 is manipulated, the fastener or other locking mechanisms contained within the locking housings 285 extend and couple the disposable cartridge 100 the fixing points 210 that are located on the exposure surface 225 of the heat exchanger. heat 101. When coupled, the force provided to couple the exposure surface 225 of the heat exchanger 101 to the plate 275 is approximately 170 pounds to 230 pounds with the normal force being around 200 pounds. Located between the exposure surface 225 and the plate 275 there is a conductive material, or silpad, which allows a very close and uniform contact between the roller and the heat exchanger. The material chosen as the silpad is a silicone-based pad, Chomerics T500®,

p0009625 supplied by Chomerics, located in Woburn, MA. The silpad allows a better thermal transfer from the plane 275 to the heat exchanger 101 than what an air interface would allow. In this Example, the silpad is approximately 0.02 inches thick, plus or minus 0.005 inches, and covers the entire deck. In addition, in this example the surface area of ​​the flat plate 801 that makes contact with the heating element or stage is approximately 35 square inches.

p00097For the purposes of this Example, the fluid that is infused into the patient is blood. The fluid entering the pump system incorporated in this Example is at 20 ° C. The rate at which the infusion is carried out is 1000 ml / min. The pump contained within the pump housing in this Example is capable of pumping the fluid at a rate of 10 ml / hour at 1200 ml / min.

p0009835 Once the cartridge is engaged, the roller pump contained within the pump housing will apply pumping pressure to the pump loop 104 causing the causing fluid to flow from a source of fluid through the cartridge sufficient for infusion to 1000 ml / min Referring again to Figure 1, blood is introduced into the primary inlet tube 102 and proceeds beyond a first t-junction that serves as the incoming flow pressure monitor 103. The incoming flow pressure monitor 103 is in fluid communication with a first air chamber 151. The incoming flow pressure monitor 103 determines the blood flow pressure as it enters the pump loop 104 to allow adequate blood flow regulation.

p00099The incoming flow pressure monitor 103 controls the negative pressure in the event that the fluid remains

p00100Four. Five inside the disposable cartridge, but that is not flowing in the direction of the patient. Such a circumstance could arise if the fluid source bag collapses, but nevertheless fluid remains in the cartridge. If the pressure in the incoming flow pressure monitor 103 falls below 1 mmHg, then the pump will stop pumping.

p00101When blood leaves the pump loop 104 it flows through a second t-junction that serves as the outgoing flow pressure monitor 105. The outgoing flow pressure monitor 105 determines the blood pressure as it leaves the outlet. pump loop 104 so that blood flow through disposable cartridge 100 can be regulated. The outgoing flow pressure monitor measures the pressure of the fluid that comes through the cartridge. Here, the pressure is controlled to block the flow so that when the pressure exceeds 500

p0010255 mmHg the pump will shut down to prevent damage.

p00103The blood is then passed through the heat exchanger 101 through the inlet access of the exchanger 106. The heat exchanger 101 of this example is created from two halves as shown in Figure 3. The two halves are created. From the same mold in such a way that inverting a mold and fixing the two joints creates the heat exchanger. The material used in the creation of the heat exchanger of this Example was anodized aluminum. The use of this material meets the objective of the present invention by creating a large differential mass between the heat exchanger and the fluid, the blood, which is heated. The heat conduction capacity of anodized aluminum allows excellent dissipation of thermal energy through the heat exchanger. The surface of the anodized aluminum creates such an inert biological surface to avoid both the reaction with, or the adsorption of, biological material, while the blood or other fluid is passed through it. In the present example, treat with protein adsorption, blood on the surface of the material

p00104It can generate a trigger of the coagulation cascade. Proteins adsorbed on the inner surface of the heat exchanger, even if they do not activate the coagulation cascade, can be degraded and separated. Once separated from the surface of the heat exchanger, these degraded or denatured proteins can react with other proteins or cells contained in the blood in harmful ways. Anodized surface

p001055 The interior of the heat exchanger therefore prevents any damage to the blood as it passes through the heat exchanger.

p00106When a cartridge according to the present invention is used, the effective heat exchange of the heat exchanger to the infusing fluid achieves an appropriate increase in the fluid temperature without having to expose the fluid to a temperature of 45 ° C or more. Instead of having regions of varied temperature to which the blood or fluid is exposed, the constant temperature of the heat exchanger allows a more efficient transfer of thermal energy to the blood. At a flow rate of 1000 ml / min, reaching a fluid outlet temperature of 37 ° C means never having to expose the blood to a temperature of 45 ° C, which could be harmful to the fluid being infused. In fact, when using anodized aluminum, an efficiency of 95-96% has been achieved in

p00107fifteen the transfer of thermal energy to the blood sufficient to generate a 17 ° C increase in temperature.

p00108Once the blood enters the heat exchanger, the blood fills the flow cavity before proceeding through the entire heat exchanger. Blood fills the first flow cavity due to the narrow flow area created by the flow fin that defines the flow cavity. By creating a smaller flow path for the flow over the first fin, as shown in Figure 7, blood will not cross the longitudinal axis of the heat exchanger before it fills the flow cavity causing the flow pattern Flow through the fins of the exchanger has a shape similar to a wide belt.

p00109The fins used in the heat exchanger described in Figures 2a-c are spaced at approximately

p0011025 10.2 mm (0.4 inches). The depth of the flow path created by the separation of the two pluralities of fins is approximately 2.03mm (0.08 inches). The fins are approximately 109 mm (4.3 inches) wide and 15.75 mm (0.62 inches) high. This creates a linear flow distance ratio with respect to width of approximately 1: 7. The flow fin 303, as seen in Figure 3, is wider than the rest of the fins through the heat exchanger. This greater width of the flow fin 303 creates a narrower flow path in said fin when the two halves of the heat exchanger are connected. In this Example, the width of the flow path created by the flow fin 303 is approximately 0.76 mm (0.03 inches). Since the blood flowing through the heat exchanger in this Example will travel along a path of least resistance, the flow cavity 304 will be filled before the blood travels beyond the flow fin 303. The blood then travels through the fins, it is created by a turbulent flow pattern in the

p0011135 blood as it travels through the heat exchanger. This turbulent flow ensures an increased exposure of more molecules within the blood fluid to the heat exchanger thereby increasing an efficient transfer of thermal energy.

p00112Once the blood flow reaches the upper part of the heat exchanger, it exits through the outlet access of the exchanger 107 which is located in a position opposite the inlet access of the exchanger 106 of the heat exchanger 101. At this point , the infusion fluid has withstood its heating and the desired temperature has been reached. Then, the blood enters the air trap 110 in a position approximately midway between the top and bottom of the longitudinal axis of the air trap 110. In this Example, the air trap is approximately 107 mm (4, 2 inches) along its axis

p00113Four. Five longitudinal, vertical and approximately 25.4 mm (1 inch) in diameter. The air trap inlet access 503 is located approximately 53.3 mm (2.1 inches) from the bottom of the air trap (see Figure 6). As blood is passed through the air trap inlet access, blood moves in a clockwise direction as blood fills the air trap. This flow of blood clockwise creates a vortex of fluid in the air trap. The fluid flow disruptor 601, which in this Example extends from the inner surface of the bottom of the air trap to approximately 12.7 mm (0.5 inches), creates a sufficient pressure differential in the access of 505 fluid outlet to draw blood and not all trapped air.

p00114Air can be trapped in the blood in this Example through several mechanisms. By adding the

p0011555 blood as it is attached to the infusion pump system, essentially failing to properly purge the blood source before fixation to the system. In addition, heating the fluid itself can cause the release of the gas stored in the blood, which can be harmful if it is introduced into the patient.

p00116As the amount of air in the air trap 110 increases, the blood level in this Example falls within the air trap. When the blood is below the lower level sensor 506, which in this Example is an ultrasonic sensor, the valve in the fluid outlet port 505 is closed. When the valve in the fluid outlet port 505 is closed, the valve is opened in the air outlet port 504 which is located at the top of the air trap. This increases the volume of blood in the air trap by forcing the air to exit 65 from the air outlet 504. The ultrasonic sensors are located in the pump housing.

p00117250 The ultrasonic sensors use the silicon buttons attached to the air trap in the lower level sensor 506 and in the upper level sensor 507 in order to effectively control the level of fluid in the air trap. When the blood level rises above the upper level sensor 507, also an ultrasonic sensor, the valve in the air outlet 504 closes. Approximately at the same time that the valve in the air outlet port is closed, the valve in the fluid outlet port 505 opens and the blood leaves the air trap and continues

p001185 towards the patient.

p00119In this Example, the fluid is then passed through a third pressure monitor that controls the overall flow within the cartridge based on the pressure. If there is a blockage, and the pressure starts to rise, this pressure monitor will try to keep the pressure within an acceptable range, which can be between 100 and 300 mmHg.

p0012010 If the pressure in this pressure monitor rises above 500 mmHg the pump will shut down.

p00121In the present example, however, before blood reaches the patient, it is passed through the out-of-flow bubble detector 112 (see Figure 1). The out-of-flow bubble detector analyzes the blood on its path to the patient to determine that the air trap has removed potentially harmful air from the system.

p00122fifteen The bubble detector of this Example uses an ultrasonic sensor that sends a signal through the tube. Air bubbles present in the system will attenuate the signal. The system will turn off the pump if bubbles as small as 30 to 50 μL are detected. The system is capable of detecting bubbles of this size at a maximum flow rate of 1200 ml / min.