Infusion fluid heat exchanger and cartridge

ES 2 575 237 T3

DESCRIPTION

Air trap for an infusion cartridge

Field of the invention

The present invention is directed to a warming fluid for infusion into the body of a patient without damaging the fluid through exposure to increased temperature as well as preventing the introduction of air into the body of the patient.

Background

The fluid required in treating a patient must often be stored cold at temperatures relatively cold relative to the patient's body temperature. This refrigerated storage is often necessary to preserve fluids in a state so that the function and integrity of the fluid is maintained. Fluids such as blood and other body fluids are often 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 function as required. It is known that injecting cold fluids into a patient's body can create a significant source of heat loss by conduction within the patient, often putting the patient at additional risk by cooling, too rapidly, or at room temperature. that physiological damage can occur.

However, during heating or when increasing the temperature of the liquid, 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 45 ° Celsius, hemolysis, the destruction or severe degradation, of blood cells can occur. Similarly, if the fluid becomes too hot and then enters the patient's body, physiological damage resulting from exposure to excessive temperatures, such as burns or other scars , can occur . Heating the fluid by volume generally requires too intense an application of a heat source to heat the entire fluid with any level of time efficiency. Similarly, heating the fluid for a prolonged period of time can lead to increased exposure of the material to the environment creating risks of contamination.

Introducing the fluid into the patient requires an adjustable flow so that the appropriate amount of fluid depending on need is delivered to the patient. Combining the fluid delivery medium with adequate and effective fluid heating is crucial for the correct delivery of fluid to the patient. The prior art contains fluid systems for warming as they are infused into a patient. The way fluids are heated within these systems varies and can be done through convection or conduction. An example of a system that poses clinical problems heats the fluid that is being delivered 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 - warming fluid. Such a system often places a conduit through a liquid such as water, which is then heated, and the fluid to be delivered to the patient is drawn through the conduit thereby increasing the temperature of the fluid that is being delivered. it has 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, taking a significant time to reach that temperature, or reaching a stasis when a cold mass (such as a bag of cold fluid) is introduced.

Also, during some fluid infusion procedures it is beneficial to adjust the patient's body temperature, either by heating it or by 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 cases of massive or emergent fluid loss, 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 by exposure to temperatures that could damage the fluid because the fluid must heat up very quickly. Such problems remain largely unsolved by the art, and the need for better in-line fluid infusers is abundant.

When fluid is introduced into a patient's body it is crucial that no air is drawn into the patient's body. Introducing air or air bubbles into a patient's body can have very detrimental effects. Air embolisms can occur if air builds up in a patient's bloodstream resulting in cardiac arrhythmias, strokes, or pulmonary heart attacks. Any of these potential illnesses can be life threatening and situations where large volumes of bodily fluids are being infused need to be minimized. It is therefore extremely important that during infusion of bodily fluids that both the air in the infusion system be controlled and that the introduction thereof into the patient's body is avoided.

ES 2 575 237 T3

Devices of the prior art that attempt to heat fluid by infusion in the body often suffer from very specific problems. For example, the heating system described in US Patent No. 3,590,215 issued to Anderson et al. uses different regions of heat than the fluid encounters as it moves through the system. Specifically, the heating element or elements described in Anderson et al. they decrease the heat in the material that heats the fluid from a higher temperature, at which the fluid enters the heat exchanger, to a lower temperature, at which the fluid leaves the heat exchanger. Not only does such a setup make it difficult to regulate the temperature of the fluid as the flow rate changes, it also runs the risk of having to expose the fluid to temperatures above which the fluid should be exposed, running the risk. of damaging the fluid.

Similarly, the meandering fluid flow path described in Anderson et al. creates the typical laminar flow observed in most heat exchanger systems. For example, United States Patent No. 5,245,693 to Ford et al. 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 type flow path. A non-turbulent flow path requires additional thermal energy to enter the fluid system to raise the temperature of the fluid system uniformly to a desired temperature.

GB 1 407 982 A discloses an air trap according to the preamble of claim 1.

Summary of the invention

The present invention provides an air trap according to claim 1.

The present invention also provides better air control in the infusion system such as to avoid introduction of air into the body of the patient who is receiving the fluid infusion.

Also disclosed is a system for increasing the temperature of a fluid being infused into a patient's body while the infusion is being performed. Such a heating system is also known as an in-line heating infusion system. A system pump provides a variable flow rate that serves a wide range of infusion needs and purposes.

A disposable cartridge will allow efficient transfer of thermal energy to the fluid being infused into the body of the patient. The cartridge will further ensure that harmful amounts of air are not drawn into the patient's body.

Brief description of the drawings

Figure 1 is an elevational view of the internal elements of a disposable cartridge in accordance with the present invention.

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

Figure 2b shows the side of the disposable cartridge of one embodiment of the present invention abutting the pump housing.

Figure 2c shows the exposed platen pump housing depicting one face of the present invention.

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

Figure 4 is a cross section of the heat exchanger, artificially hollowed out, showing a fluid flow path in accordance with one embodiment of the present invention.

Figure 5 is an exterior view of an air trap in accordance with the present invention.

Figure 6 is a cross section of an air trap in accordance with the present invention.

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

Figure 8 shows a disposable cartridge of one embodiment of the present invention.

ES 2 575 237 T3

Detailed description of the invention

The present invention contemplates a disposable heat exchange cartridge for use in infusing fluids into the body of a patient. The disposable heat exchange cartridge is detachably attached to an infusion pump device that provides not only the energy or power required to transport heat to the fluid being infused, but also provides the pump for generating flow and mechanisms for monitoring and regulating 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 numerals are used to designate like parts throughout the drawings. Figures 1 and 2a-c describe a presently preferred embodiment of the present invention and should not be construed as limiting.

One 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 superimposed fins, creating a depth of trajectory. substantially uniform flow, where each fin has a height to width ratio of at least 1: 2, whereby the fluid enters the bottom face of the heat exchanger through a bottom port and loads a bottom flow cavity across the width of the heat exchange zone before flowing through the heat exchange zone. heat and out a top access on the top face of the heat exchanger.

The disposable fluid infusion cartridge may further comprise an air trap having upper and lower faces, an inner surface, which receives fluid from the heat exchanger, and further comprises a fluid flow disruptor and a purge mechanism. to purge air from the air trap and prevent air from passing past the air trap. The disposable cartridge of this embodiment may have a fin height to fin width ratio of about 1: 2 to 1:50, preferably about 1: 4 to 1:25, and more preferably about 1: 5 to 1:10. The height of the fins in the present embodiment can be from about 0.25 inch to about 1 inch.

The disposable cartridge of the present embodiment may have a flow path depth to fin height ratio of from about 0.01 to about 1: 1. The flow path of the heat exchange zone of the present embodiment can have a depth of about 0.01 inches to about 0.25 inches. Also, the distance between a first and second fins within the same plurality of fins can be from about 0.25 inches to about 0.5 inches. Also, the heat exchanger of the present invention can be composed of two symmetric units fixed to each other, a single unit, or be composed of at least two units fixed to each other.

The air trap of the present embodiment of a disposable fluid infusion system may be cylindrical, where the air trap is taller than it is 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 sensing mechanism to monitor the volume of fluid in the air trap. Similarly, the purge mechanism of the present embodiment may utilize a valve in a fluid outlet port and a valve in an air outlet port that work in tandem to force air out of the air outlet port as tailored. that the volume of the fluid within the air trap increases to a predetermined level. The air trap of the present embodiment can effectively remove air when moving off its vertical axis by up to 45 °.

In another embodiment of the present invention, the disposable infusion cartridge may comprise a heat exchanger comprising a closed uniform tortuous flow path containing short segments of linear flow length, creating a ribbon of fluid, greater in width than length of segments of the flow length, uniform, for enhanced exposure to the interior surface of the heat exchanger and mixing of the fluid through non-laminar flow to enhance heat transfer within the fluid.

The disposable infusion cartridge of this embodiment may further comprise a cylindrical air trap for removing air from the disposable cartridge comprising an upper and a lower face and further comprising a fluid inlet port, a fluid outlet port, and a fluid outlet port. air outlet, and a fluid flow disruptor, where the air trap creates a fluid vortex and the fluid flow disruptor creates a pressure differential at the fluid outlet port to extract the fluid from the air trap.

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 about 1: 5 to 1:10. In this embodiment, the length of the short segments of the tortuous path can be from about 0.25 inch to about 1 inch in length. Similarly, the depth of the tortuous flow path has a depth to length ratio of the short flow length segments of approximately 0.01 to 1: 1, with a specific depth of approximately 0.01 inches at about 0.25.

The heat exchanger of the present invention can create the tortuous path through at least one

ES 2 575 237 T3 plurality of fins. Within the plurality of fins, the distance between a first and second fins can be from about 0.25 inches to about 0.5 inches.

The air trap fluid flow disruptor of the current embodiment may extend from the interior surface of the air trap. In addition, the purge mechanism can use an ultrasonic sensing mechanism to control the fluid height. Similarly, the purge mechanism may utilize a valve in a fluid outlet port and a valve in an air outlet port that work in tandem to force air out of the air outlet port as volume increases. fluid inside the air trap. In addition, the valves of the purge mechanism can be controlled by control mechanisms contained within a pump housing reversibly attachable to the cartridge.

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

The heat exchanger 101, as depicted in Figure 1, is contained within the disposable cartridge 100. The disposable cartridge is detachably attached to the pump system such that upon completion of the treatment, the disposable cartridge can be removed and discarded. The disposable cartridge is self-contained and once connected to the pump system does not need to be adjusted or manipulated. Fluid enters the disposable cartridge at primary inlet tube 102 which draws fluid from the fluid source. Fluid enters the primary inlet tube 102 and proceeds past a first tee that serves as the inflow pressure monitor 103. The inflow pressure monitor 103 is in fluid communication with a first flow chamber. air 151. The incoming flow pressure monitor 103 determines the pressure of the fluid flow as it enters the pump loop 104 to allow for proper regulation of the fluid flow. The pump loop 104 interacts with a rolling or otherwise detachable pressure system. The pump loop 104 in its interaction with a pumping system pushes the fluid through the disposable cartridge 100. As fluid exits the pump loop 104 it flows through a second tee that serves as the outflow pressure monitor 105. The outflow pressure monitor 105 determines the pressure of the fluid as it exits the loop. of pump 104 so that the flow of fluid through disposable cartridge 100 can be regulated.

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

Fluid exits heat exchanger 101 through exchanger outlet port 107 and then enters air trap 110 at approximately the midpoint along the longitudinal axis of air trap 110. Fluid flows out of the air trap 110 and through a third tee junction serving as the 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 out-of-flow bubble detector 112, the system will not allow infusion of that fluid into the patient's body. If the fluid does not contain air, or a minimal amount of air such that it is acceptable, the fluid is passed to the bubble detector out of flow and to the patient through the primary outlet tube 111.

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 port 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 are the same size and are spaced equidistant from each other. As fluid enters heat exchanger 101 through exchanger inlet port 106, fluid fills flow cavity 304 defined by interior walls of heat exchanger and flow fin 303. When in operation, the heat exchanger is oriented in such a way that a lower face, where the inlet orifice is located, and an upper face, where the outlet orifice is located, are oriented in a vertical way forcing the fluid to flowing in an upward direction through the heat exchanger and against gravitational forces. Due to the special shape given to flow fin 303, fluid fills flow cavity 304 before proceeding through heat exchanger 101.

Figure 4 is used to describe the flow of fluid through the heat exchanger 101, the fluid entering 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 over the first fin. This preliminary fill allows the fluid to fill the width of the heat exchanger and flows as a wide ribbon of fluid through the opposing fins in laminar flow through a long but narrow conduit. Flow flap 303 performs proper fluid diffusion by creating a thinner flow vacuum 305 between flow flap 303 and the first of the plurality of regularly shaped flaps. The fluid then flows up to the length of the

ES 2 575 237 T3 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 waveform like a shallow but wide ribbon of fluid. The wide flow, linear short path flow pattern created by the heat exchanger creates a turbulent flow that causes increased molecular circulation within the fluid. While laminar flow within typical conduits, such as tubes, see higher molecular "turns" in the central portion of the conduit, turbulent flow within heat exchanger 101 provides much more exposure of different molecules to the interior surface of the exchanger. of heat thus facilitating a more efficient and effective energy transfer.

Returning to Figure 3, the other half of the heat exchanger can be created from the same mold, where the inlet port of the exchanger 106 becomes the outlet port of the exchanger. Once formed, the two halves are assembled 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 fixation tabs 306 can be used to house the fixation devices.

Figure 4, the cross-sectional view of the heat exchanger, further shows the seal seat 401 which provides a space to place a seal around the circumference of the heat exchanger to increase the fluid impermeability of the heat exchanger, such as like an o-ring. It should be noted that although the heat exchanger of the present embodiment is described as being formed from two identical halves, the heat exchanger could be formed as a single piece or more than two pieces. To facilitate manufacture, however, two identical halves as described herein allow the proper result through lower cost.

The heat exchanger of the present invention can be formed from any number of materials: cast anodized aluminum, copper, gold, and the like. The material chosen for use in the heat exchanger of the present invention must be capable of conducting and dispersing adequate heat to ensure correct 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 by one unit per unit mass, the material with a higher mass will more efficiently transfer heat to the material with a mass less. This level of efficiency is often understood as thermal capacitance - because materials with higher thermal capacitance (i.e. mass) will retain more heat during energy transfer to the adjacent material enough to greatly increase the temperature of the second material without unwanted loss. of energy. By analogy, the heat exchange occurs between the heat exchanger and the infusion fluid for 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 having a mass of 0.5 kg at a temperature of 40 ° C. When heating is complete, both materials reach a temperature of 55 ° C. The energy stored by the hotter 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 consideration of the mass of the material, as well as the thermodynamic properties of that material.

Figure 5 shows an enlarged view of the air trap 110 and its connecting conduits. Although the air trap is described with reference to specific shapes, it should be apparent to one skilled in the art that any shape that allows reversal of the direction of fluid flow at the fluid outlet port of the air trap will allow the tracking and eliminating air from the cartridge system. The air trap is generally cylindrical in shape with a domed top 501 and a flattened bottom 502. Fluid enters the air trap 110 at the air trap inlet port 503 which is located approximately midway through the air trap. 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 may come from the lack of purging in the air fluid source prior to 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. Fluid exits air trap 110 through fluid outlet port 505 located at the bottom 502 of the air trap.

Figure 6 represents a cross section of the air trap 110. In this view, the inlet port of the air trap 503 can be seen as it is at the interface with the air trap. The air trap inlet port 503 is smoothed toward the interior wall of the air trap and is positioned off the midline of the longitudinal axis of the air trap. This position of the air trap inlet port 503 relative 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 at a clockwise direction as fluid fills and continues to enter the air trap. This flow pattern creates a vortex in the air trap pulling air down toward the fluid outlet port. At the bottom 502 of the air trap is a flow disruptor 601 that is located adjacent to the fluid outlet port 505. The flow disruptor can extend from the interior wall of the air trap or from the interior wall from the bottom 502 of the air trap. Since the fluid, which is traveling clockwise over the air trap, flows through the flow disruptor 601, a pressure differential is created at the fluid outlet port 505 drawing the fluid out of the air trap.

ES 2 575 237 T3 air and allowing air or gas bubbles to flow upward along the longitudinal axis of the air trap.

Returning to Figure 5, the fluid level within the air trap is continuously monitored while the infusion device is being operated. When the fluid level in the air trap 110 drops below the lower level sensor 506 a valve located in or on the fluid outlet port 505 closes. At about the same time that the valve in or on the fluid outlet port 505 closes, a valve in or on the air outlet port 504 opens. With fluid outlet port 505 closed, fluid entering air trap 110 forces any air present in the air trap up the longitudinal axis of the air trap. Because the air outlet port 504 is open, the air within 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 air trap 110 rises above upper level sensor 507, valve in air outlet port 504 closes. At approximately the same time that the valve in the air outlet port 504 closes, the valve in the fluid outlet port 505 opens again. With the 505 fluid outlet port open, the fluid flowing to the patient through the primary outlet tube is restored

111.

The air trap depicted in the present invention is capable of operating at different inclinations and orientations. The cylinder formed by the air trap is between 3 inches and 10 inches in height, preferably between 3.5 inches and 7 inches, and more preferably between 4 inches and 6 inches. The diameter of the air trap cylinder is between 0.5 inches and 2 inches, preferably between 0.625 inches and 1.5 inches, and more preferably between 0.75 inches and 1.25 inches. The air trap is capable of adequately removing air from the fluid as it is passed through it, even when the air trap is tilted off its vertical axis by up to 45 °.

As mentioned above, the efficient transfer of heat from the heating element to the fluid being heated strongly impacts the present invention. The use of the present invention of a wide, short linear path flow pattern allows for a more turbulent flow with a very large contact area. The contact area that is described is the area of ​​the interface between the heat exchanger and the fluid that is passed through it. Described as a ribbon of fluid, fluid traveling through a heat exchanger made in accordance with the present invention will flow 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 it is long, and longer than it is deep, thereby creating a tortuous ribbon shape for fluid to pass through. Figure 7 is a representation of the fluid flowing through the heat exchanger 100. The fluid flow of Figure 7 is shown first as having filled the inlet port of the exchanger as an inlet fluid 701. The fluid then fills the flow cavity as the fluid in the cavity 702. The fluid then 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 by the short flow length segments, is less than the flow width ω. The ratio of the linear flow distance λ to the flow width ω can be about 1: 2 to 1:50, preferably 1: 4 to 1:25, and more preferably 1: 5 to 1:10. It is the relationship between the linear flow distance and the flow width that creates the ribbon-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. Introducing turbulence into the fluid prevents the laminar-type flow that such a meandering flow path 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 at the interface allowing for improved heat transfer. Similarly, this turbulent flow creates greater contact between the molecules in the fluid flowing through the heat exchanger. With greater contact between the molecules in the fluid, greater heat exchange and transfer can occur conducting effective heat exchange from the exchanger to the fluid to be delivered to the patient.

A heat exchanger manufactured in accordance with the present invention creates this turbulent flow path and maintains it as the fluid flows along the fins. The fins, as depicted in Figure 3, create one half of the flow path for the fluid to follow. The fins on the same side of the heat exchanger are equally dimensioned and spaced, that is, the distance between a first fin 307 and a second fin 308 is the same throughout the entire interval of the heat exchanger. For the purposes of heat transfer involving a fluid flowing in the heat exchanger, the distance between a first and second fins of the same plurality of fins can be 0.25 inches to 0.5 inches, preferably 0.35. inches to 0.45 inches, and more preferably 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 can be from about 0.25 inches to 1.0 inches, preferably from 0.5 inches to 0.8 inches, and more preferably from 0.6 inches to 0.7 inches. The flow path also contains a depth element created by the distance between the top of the fins in a first plurality of fins and the valley between two fins in a second plurality of fins. The flow path can have a depth of approximately 0.01

ES 2 575 237 T3 inches to 0.25 inches, preferably 0.03 inches to 0.125 inches, and more preferably 0.04 inches to 0.110 inches. The width of the fins can be 3 inches to 6 inches, preferably 3.5 inches to 5 inches, and more preferably 4 inches to 4.5 inches.

Thermal energy transfer to the heat exchanger occurs in the exposed portion of the heat exchanger, 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 removably attached to the pump system through a first attachment region 803 and a second region fixing 804. The attachment regions allow the disposable cartridge to be attached to the pump system securely and firmly. It is extremely important that the flat plate 801 of the heat exchanger is located as close as possible to the heating element or platen. 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 platen. It is even known that with smooth materials, when it comes to solids, they are rarely fully in contact when considered on a microscopic level. Therefore, the flat plate 801 must be as uniform and smooth enough as possible in order to get as much surface area as possible in contact with the heating element or platen. The surface area of ​​the flat plate 801 that contacts the heating element or platen may 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 about 30 inches. square to approximately 45 square inches. Likewise, the pressure exerted on the disposable cartridge 100 to hold the flat plate 801 in close contact with the heating element or platen must be increased if the surface of the flat plate 801 and the heating element or platen are not smooth. If the flat plate 801 and the heating element or platen are immediately placed next to each other, an air interface is considered to exist between the two surfaces. Because while the surfaces are extremely close and pressure is exerted on the flat plate, to press the two surfaces together 801, the gaps between the surfaces will remain. Accordingly, it is possible to reduce these gaps by coating the heating element or platen that contacts the flat plate 801 of the heat exchanger with a heating pad that fits and fills the voids between the surfaces with a material that is a conductor. heat better than air while still allowing a reasonable contact pressure to be used. If air serves as the interface between the surface of the flat plate 801 of the heat exchanger and the heating element or platen, then the greatest pressure must be exerted on the system in order to achieve 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 establish with a lower and more reasonable pressure applied to the surface interface.

Example

An infusion system under the present invention is 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 visible extending out of the outer cover 201 in the right portion of the figure. The outer cover of the disposable part is made of strong 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 shell 201. The exposure surface 225 of the heat exchanger 101, which will come into contact with the stage of the pump system, 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 platen 275 that provides the thermal energy to the heat exchanger contained within the disposable cartridge. All the elements of this Example are in fluid connection with each other.

The coupling handle 280 allows the user to reversibly connect the disposable cartridge 100 to the pump housing 250 by clamping or other locking mechanisms that extend from the locking housings 285 located on the platen 275. When the coupling handle 280 is manipulated, the clamp or other locking mechanisms contained within the locking housings 285 extend and engage the disposable cartridge 100 the attachment points 210 that are located on the exposure surface 225 of the heat exchanger. heat 101. When engaged, the force provided to engage the exposure surface 225 of the heat exchanger 101 to the platen 275 is approximately 170 pounds to 230 pounds with the normal force being about 200 pounds. Located between the exposure surface 225 and the platen 275 is a conductive material, or silpad, that allows 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®, supplied by Chomerics, located in Woburn, MA. The silpad allows for better heat transfer from the 275 board to the 101 heat exchanger than 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 platen. Also, in this example the surface area of ​​the flat plate 801 that contacts the heating element or platen is approximately 35 square inches.

For the purposes of this Example, the fluid that is infused into the patient is blood. The fluid entering the system

ES 2 575 237 T3 pump 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 fluid at a rate of 10 ml / hour to 1200 ml / min.

Once the cartridge is attached, 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 fluid source through the cartridge sufficient for infusion at 1000 ml / min. Referring again to Figure 1, blood is introduced into primary inlet tube 102 and proceeds past a first tee 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 pressure of the blood flow as it enters the pump loop 104 to allow adequate regulation of blood flow.

The inflow pressure monitor 103 controls the negative pressure in the event that the fluid remains within the disposable cartridge, but is not flowing in the direction of the patient. Such a circumstance could arise if the fluid source bag collapses, but fluid remains in the cartridge nonetheless. If the pressure on the incoming flow pressure monitor 103 drops below 1 mmHg, then the pump will stop pumping.

As blood exits the pump loop 104 it flows through a second tee junction that serves as the outflow pressure monitor 105. The outflow pressure monitor 105 determines the pressure of the blood as it exits the outlet. loop pump 104 so that the flow of blood through disposable cartridge 100 can be regulated. The outflow pressure monitor measures the pressure of the fluid coming through the cartridge. Here, the pressure is controlled to block the flow so that when the pressure exceeds 500 mmHg the pump will shut off to prevent damage.

The blood is then passed through the heat exchanger 101 through the inlet port of the exchanger 106. The heat exchanger 101 in this example is created from two halves as shown in Figure 3. The two halves are created starting from the same mold in such a way that inverting a mold and fixing the two together creates the heat exchanger. The material used in creating the heat exchanger in this Example was anodized aluminum. The use of this material fulfills 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 anodized aluminum surface creates such an inert biological surface to prevent both reaction with, or adsorption of, biological material, while blood or other fluid is passed through it. In the present example, dealing with protein adsorption, blood on the surface of the material can trigger the clotting cascade. Proteins adsorbed on the inner surface of the heat exchanger, even if they do not activate the coagulation cascade, can degrade and separate. 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 damaging ways. The inner anodized surface of the heat exchanger therefore prevents any damage to the blood as it passes through the heat exchanger.

When using a cartridge in accordance with the present invention, effective heat exchange from the heat exchanger to the fluid being infused achieves an appropriate increase in fluid temperature without having to expose the fluid to a temperature of 45 ° C or more. . Rather than having regions of varying temperature that blood or fluid is exposed to, the constant temperature of the heat exchanger allows for 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 detrimental to the fluid being infused. In fact, using anodized aluminum has achieved an efficiency of 95-96% in the transfer of thermal energy to the blood sufficient to generate a 17 ° C increase in temperature.

Once 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 flap that defines the flow cavity. By creating a smaller flow path for flow over the first fin, as depicted in Figure 7, the blood will not pass through the longitudinal axis of the heat exchanger before it fills the flow cavity causing the pattern of flow through the fins of the exchanger has a shape similar to a wide ribbon.

The fins used in the heat exchanger described in Figures 2a-c are spaced approximately 0.4 inches. The depth of the flow path created by the separation of the two pluralities of fins is approximately 0.08 inches. The fins are approximately 4.3 inches wide and 0.62 inches high. This creates a linear flow distance to width ratio of approximately 1: 7. 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 the flow fin when the two halves of the heat exchanger are connected. In this Example, the width of the flow path created by flow fin 303 is approximately 0.03 inches. Since the blood that

ES 2 575 237 T3 flows through the heat exchanger in this Example will travel along a path of least resistance, flow cavity 304 will fill before blood travels past flow flap 303. Blood It then travels through the fins, created by a turbulent flow pattern in the 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 efficient heat energy transfer.

Once the blood flow reaches the top of the heat exchanger it exits through the outlet port of the exchanger 107 which is located in a position opposite to the inlet port 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. The blood then enters air trap 110 at a position approximately midway between the top and bottom of the longitudinal axis of air trap 110. In this Example, the air trap is approximately 4.2 inches at along its longitudinal axis, vertical and approximately 1 inch in diameter. The air trap inlet port 503 is located approximately 2.1 inches from the bottom of the air trap (see Figure 6). As the blood passes through the air trap inlet port, the blood moves in a clockwise direction as the blood fills the air trap. This clockwise flow of blood creates a fluid vortex in the air trap. Fluid flow disruptor 601, which in this Example extends from the interior surface of the bottom of the air trap to approximately 0.5 inches, creates a sufficient pressure differential at the fluid outlet port 505 to extract blood and not all trapped air.

Air can be trapped in the blood in this Example through several mechanisms. By adding the blood as it is attached to the pump system for infusion, essentially failing to properly purge the source of the blood prior to attachment to the system. Furthermore, heating of the fluid itself can cause the release of gas stored within the blood, which can be harmful if introduced into the patient.

As the amount of air in the air trap 110 increases, the blood level in this Example drops 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 closes. When the valve in the fluid outlet port 505 is closed, the valve in the air outlet port 504 located at the top of the air trap opens. This increases the volume of blood in the air trap forcing air out of the air outlet port 504. The ultrasonic sensors are located in the pump housing 250. 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 fluid level 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 port 504 closes. At approximately the same time that the valve in the air outlet port closes, the valve in the fluid outlet port 505 opens and the blood exits the air trap and continues to the patient.

In this Example, the fluid is then passed through a third pressure monitor that controls the overall flow within the cartridge based on 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. If the pressure on this pressure monitor rises above 500 mmHg the pump will shut off.

In the present example, however, before the 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 way to the patient to determine that the air trap has removed potentially harmful air from the system. The bubble detector in this Example uses an ultrasonic sensor that sends a signal through the tube. Air bubbles in the system will attenuate the signal. The system will shut down the pump if bubbles as small as 30 to 50 pL are detected. The system is capable of detecting bubbles of this size at a maximum flow rate of 1200 ml / min.

The following points are further disclosed.

1. A disposable fluid infusion cartridge comprising

to. a heat exchanger comprising upper and lower faces and an internal heat exchange zone defined by first and second plurality of superimposed fins, creating a substantially uniform flow path depth, where each fin has a height-to-height ratio to the width of at least 1: 2, whereby the fluid enters the bottom face of the heat exchanger through a bottom port and fills a bottom flow cavity across the width of the heat exchange zone before flowing through the heat exchange zone. heat and out of an upper access on the upper face of the heat exchanger; me

b. an air trap comprising upper and lower faces, comprising an inner surface, which receives the fluid from the heat exchanger further comprising a fluid flow disruptor and a

ES 2 575 237 T3 purge mechanism to purge air from the air trap and prevent air from passing past the air trap.

two. The point cartridge 1, where the ratio of the height of the fins to the width of the fins is approximately 1: 2 to 1:50.

3. The cartridge from point 1, where the ratio of the height of the fins to the width of the fins is approximately 1: 4 to 1:25.

Four. The cartridge of item 1, where the ratio of the height of the fins to the width of the fins is approximately 1: 5 to 1:10.

5. The cartridge from point 1, where the height of the fins ranges from about 0.25 inch to about 1 inch.

6. The cartridge from point 1, where the ratio of the depth of the flow path to the height of the fins is approximately 0.01: 1 to 1: 1.

7. The cartridge at point 1, where the heat exchange zone flow path has a depth of about 0.01 inch to about 0.25 inch.

8. The cartridge of point 1, where the distance between a first and second fins within the same plurality of fins is from about 0.25 inches to about 1 inch.

9. The cartridge from point 1, where the heat exchanger is made up of two symmetrical units fixed to each other.

10. The cartridge from point 1, where the heat exchanger is made up of a single unit.

eleven. The cartridge of point 1, where the heat exchanger is composed of at least two units fixed to each other.

12. The cartridge from point 1, where the air trap is cylindrical.

13. The cartridge from point 12, where the air trap is taller than it is wide.

14. The cartridge at point 1, where the fluid flow disruptor extends from the inner surface of the bottom face of the air trap.

fifteen. The cartridge from point 1, where the purge mechanism uses an ultrasonic sensing mechanism to monitor the volume of fluid in the air trap.

16. The cartridge at point 15, where the bleed mechanism uses a valve in the fluid outlet port and a valve in the air outlet port that work in tandem to force air out of the air outlet port as that the volume of fluid within the air trap increases to a predetermined level.

17. The cartridge from point 1, where the air trap can effectively remove air when moving off the vertical axis by up to 45 [deg.].

18. The cartridge from item 1, where the heat exchanger has a surface area exposed to a heating element of about 30 square inches to about 45 square inches.

19. The cartridge at point 18, where the surface area is substantially flat across said area.

twenty. A disposable infusion cartridge comprising:

to. a heat exchanger comprising a closed uniform tortuous flow path containing short segments of linear flow length, creating a ribbon of fluid, greater in width than linear flow length segments, for improved exposure to the interior surface of the heat exchanger; me

b. a cylindrical air trap for removing air from the fluid comprising an upper and lower face and further comprising an upper fluid inlet port, a lower fluid outlet port, an upper air outlet port, and a pressure switch. fluid flow, where the air trap creates a fluid vortex and the fluid flow disruptor creates a pressure differential at the fluid outlet port to extract fluid from the air trap.

ES 2 575 237 T3

twenty-one. The point cartridge 20, where the ratio of the length of the short segments of the tortuous flow path to the width of the flow path is approximately 1: 2 to 1:50.

22. The cartridge at point 20, where the ratio of the length of the short segments of the tortuous flow path to the width of the flow path is approximately 1: 4 to 1:25.

2. 3. The cartridge at point 20, where the ratio of the length of the short segments of the tortuous flow path to the width of the flow path is approximately 1: 5 to 1:10.

24. The cartridge of point 20, where the length of the short segments of the tortuous flow path is from about 0.25 inches to about 1 inch in length.

25. The cartridge at point 20, where the depth of the tortuous flow path has a depth to length ratio of the short segments of approximately 0.01: 1 to 1: 1.

26. The cartridge at point 20, where the tortuous flow path of the heat exchange zone has a depth of about 0.01 inches to about 0.25 inches.

27. The cartridge at point 20, where the tortuous flow path is created by means of at least a plurality of fins.

28. The cartridge of point 20, where the distance between a first and second fins within a plurality of fins is from about 0.25 inches to about 0.5 inches.

29. The cartridge at point 20, where the fluid disruptor extends from the inner surface of the air trap.

30. The cartridge at point 20, where the purge mechanism uses an ultrasonic sensing mechanism to control the fluid height.

31. The cartridge at point 30, where the purge mechanism uses a valve in the fluid outlet port and a valve in the air outlet port that work in tandem to force air out of the air outlet port as the volume of fluid within the air trap increases.

32. The cartridge at item 30, where the purge mechanism valves are controlled by monitoring the mechanisms contained within a pump housing that can be reversibly coupled to the cartridge.

33. The 20 point cartridge, where the air trap can effectively remove air when moving off the vertical axis by up to 45 [deg.].

3. 4. The cartridge from item 20, where the heat exchanger has a surface area exposed to a heating element that is from about 30 square inches to about 45 square inches.

35. The fist cartridge 20, where the surface area is substantially flat across said area.

36. The cartridge at item 20, further comprising at least one pressure monitor for monitoring fluid pressure within the disposable cartridge.

37. The cartridge at point 20 further comprises at least one bubble detector to monitor the presence of a bubble within the fluid that is passed through the disposable cartridge.