Apparatus for extracorporeal blood treatment and method for determining water loss in a membrane gas exchanger of an apparatus for extracorporeal blood treatment - Patents.com

Abstract

The method for determining the water loss in a membrane gas exchanger of a device for extracorporeal blood treatment involves measuring the sweep gas flow rate (Q) on the gas side of the membrane gas exchanger (19). gas ) and the water saturation (C saturation_out ) and at least the sweep gas flow rate (Q gas ) and water saturation (C saturation_out ) as a function of water loss (Q eccor )

Description

[Technical field]

[0001] The present invention relates to a device for extracorporeal treatment of blood, in particular a device with a membrane gas exchanger, for example for CO2 removal, and to a method for detecting water loss in a membrane gas exchanger of a device for extracorporeal treatment of blood. [Background technology]

[0002] In the field of extracorporeal blood treatment, in hemodialysis treatment, the patient's blood and a treatment solution that is approximately isotonic with the bloodstream are circulated through separate compartments of the hemodialyzer so that impurities and undesirable substances present in the blood (urea, creatinine, etc.) can be transferred by diffusion transport from the blood to the treatment solution. The ion concentration of the treatment solution is selected to correct the ion concentration of the patient's blood. In hemodiafiltration treatment, the convective transport caused by ultrafiltration resulting from a positive pressure difference induced between the blood side and the treatment solution side of the hemodialyzer membrane is added to the diffusion transport obtained by dialysis.

[0003] In the field of extracorporeal blood treatment and therapy, membrane gas exchangers are used for extracorporeal membrane oxygenation (ECMO) and / or extracorporeal CO2 removal (ECCO2R). Initially used in dedicated systems, the development of extracorporeal CO2 removal has led to the introduction of membrane gas exchangers in recent years in dialysis systems for continuous renal replacement therapy (CRRT). Carbon dioxide CO2 is removed by diffusion from the blood through the gas exchange membrane into the gas flowing on the other membrane side (sweep gas flow). CRRT systems can provide not only ECCO2R therapy (standalone ECCO2R) but also combined CRRT and ECCO2R in the same blood circuit.

[0004] During CO2 removal, at the same time that CO2 is extracted, some of the water moves into the sweep gas flow and evaporates, leading to both heat and water loss from the blood compartment.

[0005] Fluid loss is ignored in prior art devices and introduces a systematic bias in the patient's fluid balance that is of the same order of magnitude as the fluid balance accuracy of the system.

[0006] Indeed, water evaporation into the sweeping gas flow has two main consequences. - Increases patient fluid removal in an uncontrolled manner. -Cools the blood (significant latent heat associated with water evaporation).

[0007] Aspects of fluid balance may have clinical consequences, since fluid losses through the gas exchanger are in the range of several hundreds of ml per day and may therefore be compatible with the precision required for a fluid balance system of the device.

[0008] It is therefore an object of the present invention to provide an apparatus for extracorporeal treatment of blood configured to provide a correct fluid balance to a patient during extracorporeal blood treatment in order to avoid or reduce the risk of clinical consequences to the patient.

[0009] In particular, the aim of the present invention is to improve the accuracy of existing liquid balance systems of devices for extracorporeal treatment of blood, equipped with a gas exchanger for CO2 removal.

[0010] Furthermore, it is an object to provide an apparatus capable of ensuring correct liquid balance without requiring additional specific components / devices. Summary of the Invention

[0011] At least one of the above objects is substantially achieved by a device for extracorporeal treatment of blood and a method for determining water loss in a membrane gas exchanger of a device for extracorporeal treatment of blood according to one or more of the appended claims.

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to aspects of the present invention, apparatus and methods capable of achieving one or more of the above objectives are described below.

[0013] A first aspect is an apparatus for extracorporeal treatment of blood, comprising: Optionally, a blood treatment unit; optionally an extracorporeal blood circuit coupled to said blood treatment unit; a blood pump configured to be coupled to a pump portion of the extracorporeal blood circuit; optionally, a fluid circuit coupled to the blood treatment unit; at least one membrane gas exchanger operably connected to the extracorporeal blood circuit and / or the liquid circuit for exchanging gas with blood flowing in the extracorporeal blood circuit and / or with liquid flowing in the liquid circuit, the membrane gas exchanger having a blood or liquid side having a blood or liquid inlet and a blood or liquid outlet in liquid communication with the extracorporeal blood circuit or the liquid circuit, and a gas side intersected by a sweep gas and having a gas inlet and a gas outlet; A control unit configured to command the execution of a task, said task comprising at least the following steps: - exchanging gas between the blood or liquid flowing through the blood or liquid side of the membrane gas exchanger and the sweep gas flowing through the gas side of the membrane gas exchanger; - determining the blood or liquid water loss occurring in said membrane gas exchanger due to gas exchange, - Emitting a signal indicating said moisture loss and / or at least partially, optionally automatically, compensating for said moisture loss. The present invention relates to an apparatus comprising:

[0014] A second aspect relates to a method for exchanging gases in an apparatus for extracorporeal treatment of blood, the apparatus for extracorporeal treatment of blood comprising: Optionally, a blood treatment unit; optionally an extracorporeal blood circuit coupled to said blood treatment unit; a blood pump configured to be coupled to a pump portion of the extracorporeal blood circuit; optionally, a fluid circuit coupled to the blood treatment unit; at least one membrane gas exchanger operably connected to the extracorporeal blood circuit and / or the liquid circuit for exchanging gas with blood flowing therein and / or with liquid flowing therein, the membrane gas exchanger having a blood or liquid side in liquid communication with the extracorporeal blood circuit or the liquid circuit and a gas side intersected by a sweep gas; The method comprises: - exchanging gas between the blood or liquid and the sweep gas in the membrane gas exchanger; - determining the blood or liquid water loss occurring in said membrane gas exchanger due to gas exchange, - Emitting a signal indicating said moisture loss and / or at least partially, optionally automatically, compensating for said moisture loss. The present invention relates to a method comprising the steps of:

[0015] A third aspect relates to a method for determining the water loss in a membrane gas exchanger of an apparatus for extracorporeal treatment of blood, said apparatus for extracorporeal treatment of blood comprising: Optionally, a blood treatment unit; optionally an extracorporeal blood circuit coupled to said blood treatment unit; a blood pump configured to be coupled to a pump portion of the extracorporeal blood circuit; optionally, a fluid circuit coupled to the blood treatment unit; at least one membrane gas exchanger operably connected to the extracorporeal blood circuit for exchanging gas with blood flowing therein and / or with liquid flowing therein, the membrane gas exchanger having a blood or liquid side in liquid communication with the blood circuit or the liquid circuit and a gas side intersected by a sweep gas; The method comprises: - obtaining a sweep gas flow rate on the gas side of the membrane gas exchanger; - - calculating said blood or liquid water loss as a function of at least said sweep gas flow rate.

[0016] In a fourth aspect according to any one of the preceding aspects, the membrane gas exchanger is a carbon dioxide CO2 remover, and / or the gas exchanged is carbon dioxide (CO2) and is removed from the blood or liquid, and optionally the membrane gas exchanger is an oxygenator, and / or the gas exchanged is oxygen and is added to the blood or liquid, and optionally the membrane gas exchanger is a carbon dioxide CO2 remover and oxygenator, and / or carbon dioxide (CO2) is removed from the blood or liquid while oxygen is added to the blood or liquid.

[0017] In a fifth aspect according to any one of the preceding aspects, the membrane gas exchanger includes a gas permeable membrane separating the blood or liquid side and a gas side, and optionally, the gas permeable membrane includes a plurality of hollow fibers.

[0018] In a sixth embodiment according to the previous embodiment, a sweep gas source is connected to the gas inlet for supplying a sweep gas through the gas side of the membrane gas exchanger, optionally the sweep gas is a dry gas or a humidified gas, optionally the sweep gas is air, optionally dry air or humidified air, dioxygen, or a mixture of air and dioxygen, and optionally a device for humidifying the sweep gas is disposed between the sweep gas source and the gas inlet.

[0019] In a seventh aspect according to any one of the preceding aspects, the extracorporeal blood circuit comprises a blood removal line and a blood return line connectable to a patient, the blood removal line being connected to the blood inlet of the membrane gas exchanger, and the blood return line being connected to the blood outlet of the membrane gas exchanger.

[0020] In an eighth aspect according to any one of the preceding aspects 1 to 6, the apparatus includes the blood treatment unit, and the extracorporeal blood circuit is coupled to the blood treatment unit.

[0021] In a ninth aspect according to aspect 8 above, the blood treatment unit comprises a primary chamber and a secondary chamber separated by a semipermeable membrane, the extracorporeal blood circuit comprises a blood withdrawal line connected to the inlet of the primary chamber and a blood return line connected to the outlet of the primary chamber, optionally the liquid circuit being connected to the secondary chamber, optionally the liquid circuit comprising a drain line connected to the outlet of the secondary chamber and a dialysate line connected to the inlet of the secondary chamber, optionally in at least one configuration the liquid circuit presents a closed loop connected to the secondary chamber.

[0022] In a tenth aspect according to either of the above aspects 8 or 9, the membrane gas exchanger is arranged on the blood return line or on the blood removal line, and / or the membrane gas exchanger is arranged on the liquid circuit, optionally in a closed loop.

[0023] In an eleventh aspect according to any one of the preceding aspects, determining the blood water loss comprises: - obtaining a sweep gas flow rate on the gas side of the membrane gas exchanger; - optionally obtaining the water saturation at the gas outlet of the membrane gas exchanger; - optionally obtaining the water saturation at the gas inlet of the membrane gas exchanger; - calculating the blood or liquid water loss as a function of at least the sweep gas flow rate and optionally the water saturation at the gas outlet and optionally the water saturation at the gas inlet.

[0024] In a twelfth aspect according to aspect 11 above, determining blood water loss comprises: - obtaining the relative humidity at the gas outlet of the membrane gas exchanger; - optionally obtaining the relative humidity at the gas inlet of the membrane gas exchanger; - calculating the blood water loss as a function of the relative humidity at the gas outlet and, optionally, also the relative humidity at the gas inlet.

[0025] In a thirteenth aspect according to any one of the eleventh or twelve aspects described above, acquiring the sweep gas flow rate includes: - measuring the sweep gas flow rate directly or indirectly; - collecting a prescribed value of the sweep gas flow rate.

[0026] In a fourteenth aspect according to any one of the eleventh to thirteenth aspects described above, acquiring the moisture saturation amount at the gas outlet includes: - obtaining a blood or liquid inlet temperature at the blood or liquid inlet of the membrane gas exchanger; - calculating said water saturation as a function of said blood or liquid inlet temperature, Optionally, if the sweep gas is humidified, obtaining the water saturation at the gas inlet comprises: - obtaining a humidification temperature, optionally said humidification temperature being measured or calculated or a constant default value, optionally room temperature; - calculating the water saturation at the gas inlet as a function of the humidification temperature.

[0027] In a fifteenth aspect according to the previous aspect, the blood or fluid inlet temperature is measured or calculated, or is a fixed default value.

[0028] In a sixteenth aspect according to the above-mentioned twelfth aspect or any one of aspects thirteen to fifteen in the case of the above-mentioned twelfth aspect, acquiring the relative humidity at the gas outlet includes: - deriving the relative humidity at the gas outlet from the type of the membrane gas exchanger and optionally from the type of the sweep gas flow rate; - assuming, for example if the type of the membrane gas exchanger is unknown, that the relative humidity at the gas outlet is equal to 100%; Optionally, obtaining the relative humidity at the gas inlet comprises: - if the sweep gas is humidified, assuming that the relative humidity at the gas inlet is equal to 100%; - if the sweep gas is not humidified, assuming that the relative humidity at the gas inlet is equal to 0%.

[0029] In a seventeenth aspect according to any one of the preceding aspects, at least partially compensating for the blood or liquid water loss includes adding water to the extracorporeal blood circuit or the liquid circuit, optionally via a solution, optionally via glucose or electrolyte / infusion solution.

[0030] In an eighteenth aspect according to any one of the preceding aspects, at least partially compensating for the blood or liquid water loss includes reducing net liquid removal from the extracorporeal blood circuit.

[0031] In a 19th aspect according to any one of the aforementioned aspects when according to aspect 9, the liquid circuit comprises a drain line connected to an outlet of the secondary chamber and an evacuation pump operating on the drain line, and at least partially compensating for the blood or liquid water loss includes adjusting the evacuation pump.

[0032] In a twentieth aspect according to the previous aspect, the control unit is configured to regulate the evacuation pump by adjusting, and optionally reducing, the pumping speed of the evacuation pump as a function of the calculated blood or liquid water loss.

[0033] In a twenty-first aspect according to any one of the preceding aspects, a source of water, optionally a solution, optionally a glucose solution or an electrolyte / infusion solution, is connected directly or indirectly (e.g., via a liquid circuit or an infusion line) to the extracorporeal blood circuit through a water line, and a water pump operates on the water line, and at least partially compensating for the blood or liquid water loss includes infusing water into the extracorporeal blood circuit, optionally via a solution, optionally a glucose solution or an electrolyte / infusion solution, and optionally, the water or solution infusion is not balanced by the discharge pump.

[0034] In a twenty-second aspect according to the previous aspect, the control unit is configured to adjust the flow rate of the infused water or solution in the extracorporeal blood circuit as a function of the calculated blood water loss.

[0035] In a twenty-third aspect according to any one of the preceding aspects twenty-one or twenty-two, at least partially compensating for the water loss includes adjusting the water pump.

[0036] In a twenty-fourth embodiment according to embodiment twenty-one or twenty-two or twenty-three, the water line terminates in the extracorporeal blood circuit, optionally at a mixing site to minimize hemolysis.

[0037] In a 25th aspect according to the above 24th aspect, the water line is connected to the blood circuit between the blood pump and the membrane gas exchanger, optionally between the blood pump and the blood treatment unit, and / or downstream of the membrane gas exchanger.

[0038] In a 26th aspect according to any of aspects 21 to 23 when according to aspect 9, the liquid circuit comprises a dialysate line connected to the inlet of the secondary chamber and a dialysate source, and optionally at least one dialysis pump coupled or configured to be coupled to a pump portion of the dialysate line, and the water line terminates in the dialysate line.

[0039] In a twenty-seventh aspect according to aspect twenty-six above, the water line is connected to the dialysate line at a junction located between the dialysis pump and the blood treatment unit.

[0040] In a 28th embodiment according to any one of the preceding embodiments 21 to 23, an infusion circuit comprising one or more infusion lines of substitution fluid is connected to the extracorporeal blood circuit and, optionally, at least one infusion pump coupled or configured to be coupled to pump portions of the infusion lines, and the water line terminates in at least one of the infusion lines.

[0041] In a twenty-ninth embodiment according to the previous embodiment, the water line is connected to the infusion line at a junction located between the infusion pump and the extracorporeal blood circuit.

[0042] In a 30th aspect according to aspects 28 or 29 above, the infusion line is connected to the extracorporeal blood circuit between the blood pump and the membrane gas exchanger, optionally between the blood pump and the blood treatment unit, and optionally an infusion line is connected upstream of the blood pump.

[0043] In a thirty-first embodiment according to embodiment 28 or 29 above, the infusion line is connected to the blood circuit downstream of the membrane gas exchanger.

[0044] In a 32nd embodiment, the one or more signals indicating the water loss are one or more visual signals indicative of the value of the water loss, optionally shown on a display, optionally on a control panel or a display of a remote device connected to the control unit.

[0045] In a 33rd embodiment, determining blood water loss comprises: - obtaining a sweep gas flow rate on the gas side of the membrane gas exchanger; - obtaining a blood or liquid inlet temperature at the blood or liquid inlet of the membrane gas exchanger; - obtaining room temperature; - Calculating the blood or liquid water loss as a function of at least the sweep gas flow rate and the blood or liquid inlet temperature, and optionally the room temperature.

[0046] In a thirty-fourth aspect according to any of the preceding aspects, the determining of blood water loss comprises: - calculating the moisture percentage at the gas outlet as a function of the blood or liquid inlet temperature; - calculating the moisture percentage at the gas inlet as a function of the room temperature; - Calculating the blood or liquid water loss as the difference between the moisture percentage at the gas outlet and the moisture percentage at the gas inlet.

[0047] In a thirty-fifth embodiment according to the above aspect, a parameter correlating the moisture percentage at the gas outlet and the blood or liquid inlet temperature is derived through calculation, and a parameter correlating the moisture percentage at the gas inlet and the room temperature is derived through experimental testing. [Brief description of the drawings]

[0048] Aspects of the present invention are illustrated in the accompanying drawings, which are provided as non-limiting examples. [Figure 1] 1 shows a schematic diagram of an apparatus for extracorporeal treatment of blood. [Diagram 2] 1 shows a schematic diagram of an alternative embodiment of a device for extracorporeal treatment of blood. [Diagram 3] 1 shows a schematic diagram of a further embodiment of a device for extracorporeal treatment of blood. [Figure 4] 1 is a flow chart of a method of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] A non-limiting embodiment of a device 1 for extracorporeal treatment of blood that may implement the innovative aspects of the present invention is shown in Figures 1, 2 and 3. In the following description and in Figures 1, 2 and 3, the same components are identified by the same reference numbers.

[0050] In FIG. 1, an apparatus 1 for extracorporeal treatment of blood is shown, which includes a blood treatment unit 2 (such as a blood filter, ultrafilter, hemodialysis filter, dialyzer, plasma filter, etc.) having a primary chamber 3 and a secondary chamber 4 separated by a semipermeable membrane 5, depending on the treatment, the semipermeable membrane 5 of the blood treatment unit 2 may be selected to have different properties and performances. A blood withdrawal line 6 is connected to the inlet 3a of the primary chamber 3, and a blood return line 7 is connected to the outlet 3b of the primary chamber 3. In use, the blood withdrawal line 6 and the blood return line 7 are connected to a needle or catheter or other access device (not shown), which is then placed in fluid communication with the patient "P" vasculature, so that blood can be withdrawn through the blood withdrawal line 6, flow through the primary chamber 3 and then returned to the patient's vasculature through the blood return line 7. An air separator, such as a degassing chamber 8, may be present on the blood return line 7. Furthermore, a safety return clamp 9, controlled by a control unit 10, may be present on the blood return line 7 downstream of the degassing chamber 8. For example, there may be an air bubble sensor associated with the degassing chamber 8 or coupled to the portion of the line 7 between the degassing chamber 8 and the return clamp 9. If present, the air bubble sensor is connected to the control unit 10 and sends a signal to the control unit 10 to cause the control unit 10 to close the return clamp 9 if one or more air bubbles exceeding a safety threshold are detected. Blood flow through the blood lines is controlled by a blood pump 11, e.g. a peristaltic blood pump, acting on either the withdrawal line 6 or the return line 7. The embodiment of Figures 1, 2 and 3 shows the blood pump 11 coupled to the pump portion of the withdrawal line 6. The operator can measure the blood flow rate Q through a user interface. B The control unit 10 may input a set value for blood flow rate Q B The blood pump 11 is configured to be controlled based on the

[0051] The control unit 10 may comprise a digital processor (CPU) having a memory (or memories), an analog type circuit, or a combination of one or more digital processing units and one or more analog processing circuits. In the present specification and claims, the control unit 10 is indicated as being "configured" or "programmed" to perform steps. This may in fact be achieved by any means that allows the control unit 10 to be configured or programmed. For example, in the case of a control unit 10 comprising one or more CPUs, one or more programs are stored in a suitable memory, the one or more programs including instructions that, when executed by the control unit 10, cause the control unit 10 to perform the steps described and / or claimed in connection with the control unit 10. Alternatively, if the control unit 10 is of an analog type, the circuitry of the control unit 10 is designed to include circuitry configured to process electrical signals such that, in use, the control unit 10 performs the steps of the control unit 10 disclosed herein.

[0052] A drain line 12, i.e. a spent dialysate line, is connected at one end to the liquid outlet 4b of the secondary chamber 4 and at the other end to a waste, which may be a drain conduit or a drain container that collects the liquid extracted from the secondary chamber. A drain pump 13 controls the flow rate Q across the drain line. eff The control unit 10 operates on the drain line 12 to regulate

[0053] The apparatus of Figure 1 includes a dialysate line 14 connected at one end to a source of fresh dialysate and at the other end to a fluid inlet 4a of the secondary chamber 4 of the treatment unit 2 for supplying fresh dialysate to the secondary chamber 4. A dialysate pump 15 pumps a flow rate Q dial The dialysate supply 14 operates under the control of the control unit 10 on the dialysate line 14 to supply fluid at

[0054] The drain line 12 , the dialysate line 14 and the secondary chamber 4 of the blood treatment unit 2 are part of the fluid circuit of the device 1 .

[0055] The embodiment of Fig. 1 shows an infusion line 16 connected to the blood withdrawal line 6 between the blood pump 11 and the treatment unit 2. This infusion line 16 supplies substitution fluid from an infusate container 17 connected to one end of the infusion line 16. It should be noted that instead of or in addition to the infusion line 16, the device of Fig. 1 may also include a post-dilution fluid line (not shown) connecting an infusate container to the blood return line 7 and / or to a pre-blood pump infusion line 16' with its own infusate container 17'. Furthermore, the individual flow rates Q through the infusion lines 16, 16' may be determined by the flow rate of the infusion line 16, 16'. rep To regulate , an infusion pump 18 operates on the infusion line 16 and an infusion pump 18' operates on the pre-blood pump infusion line 16'. Note that in the case of more than one infusion line (pre-dilution and post-dilution and pre-blood pump infusion lines 16'), each infusion line may be equipped with a separate infusion pump.

[0056] The device 1 for extracorporeal treatment of blood further comprises a membrane gas exchanger 19 arranged on the blood return line 7, i.e. downstream of the blood treatment unit 2 with respect to the flow direction of the blood during treatment. The membrane gas exchanger 19 comprises a gas-permeable membrane 200 separating a blood side 201 and a gas side 202. A first part 7a of the blood return line 7 coming from the blood treatment unit 2 is connected to a blood inlet 19a on the blood side 201 of the membrane gas exchanger 19, and a second part 7b of the blood return line 7 connected to a needle or catheter is connected to a blood outlet 19b on the blood side 201 of the membrane gas exchanger 19. On the gas side 202 of the membrane gas exchanger 19, separate gas inlets 19c and gas outlets 19d for a sweep gas (e.g. air or dioxygen or a mixture of air and dioxygen) are provided.

[0057] The internal structure of the membrane gas exchanger 19 may be known per se. A gas permeable membrane 200 separates the blood side 201 and the gas side 202. The gas permeable membrane 200 may include a plurality of hollow fibers defining said membrane. Blood passes around the hollow fibers (blood side) to achieve gas exchange by diffusion while a sweep or ventilation gas (e.g., dioxygen, air, dry air, humidified air) passes inside the hollow fibers (gas side). The membrane gas exchanger 19 is operatively coupled to the extracorporeal blood circuit to exchange gas with the blood flowing therein. The membrane gas exchanger 19 in the disclosed embodiment of Figs. 1, 2 and 3 is a CO2 remover. Carbon dioxide CO2 diffuses from the blood side 201 into the gas for disposal. The device 1 of Fig. 1 can provide standalone CO2 removal as well as combined dialysis and CO2 removal in the same circuit.

[0058] In other embodiments, the membrane gas exchanger 19 may be an oxygenator configured to add oxygen to the blood, or may be configured to add oxygen to the blood simultaneously with the removal of carbon dioxide CO2.

[0059] A sweep gas source 20 , such as a gas bottle, is connected to the gas inlet 19 c to supply sweep gas through the gas side of the membrane gas exchanger 19 .

[0060] In an alternative embodiment, the membrane gas exchanger 19 may be disposed on the blood removal line 6 .

[0061] A blood warmer 21 may be disposed on the blood return line 7 between the membrane gas exchanger 19 and the bubble trap 8 .

[0062] The blood removal line 6, the blood return line 7, the primary chamber 3 of the treatment unit 2, and the blood side 201 of the membrane gas exchanger 19 form part of the extracorporeal blood circuit of the device 1. The infusion lines 16, 16' form part of the infusion circuit of the device 1.

[0063] The blood pump 11, the drain pump 13, the dialysate pump 15, the infusion pumps 18, 18' and possible other pumps are operatively connected to a control unit 10 which controls said pumps. The control unit 10 is also operatively connected to sensors (such as flow and / or pressure sensors) on the blood circuit and / or the liquid circuit and / or the infusion circuit. The control unit 10 is also operatively connected to clamps and valves, such as the return clamp 9. The control unit 10 is also connected to a user interface, not shown, e.g. a graphic user interface, which receives operator input and displays device output. For example, the graphic user interface may include a touch screen, a display screen, and hard keys for entering user input, or a combination thereof. During extracorporeal blood therapy, the control unit 10 is configured to control at least the pumps 11, 13, 15, 18, 18' to ensure that a predetermined patient net fluid removal is achieved over the course of the therapy time, e.g. as required by a prescription provided to the control unit 10 via the user interface.

[0064] 1 further comprises a water line 22 connected to a source 23 of water in solution, e.g., glucose solution in a bag, and connected to the infusion line 16 at a connection point located between the injection pump 18 and the extracorporeal blood circuit. A water pump 24 controls the flow rate Q of water through the water line 22. water According to an alternative embodiment (dashed line in FIG. 1 ), the water line 22 is connected directly to the extracorporeal blood circuit between the blood pump 11 and the blood treatment unit 2 .

[0065] A further water line 22' connected to a water source 23' and coupled to a water pump 24' is connected to the dialysate line 14 at a connection point located between the dialysis pump 15 and the liquid inlet 4a of the secondary chamber 4 of the blood treatment unit 2.

[0066] The device 1 of FIG. 1 is configured to provide continuous renal replacement therapy (CRRT) in combination with ECCO2R therapy, or ECCO2R therapy alone.

[0067] The control unit 10 is configured to control the apparatus to perform treatment of the patient "P" via the extracorporeal blood treatment unit 2 and the membrane gas exchanger 19. The control unit 10 also controls the blood water loss Q that occurs in the membrane gas exchanger 19 due to CO2 removal. eccor In order to take this into account, the method is adapted to command the execution of the tasks according to the invention (FIG. 4).

[0068] The task comprises at least the following steps: - removing gas (CO2) from the blood flowing through the blood side of the membrane gas exchanger 19; - blood water loss Q occurring in the membrane gas exchanger 19 due to gas exchange (i.e. evaporation of water into the sweep gas) eccor and determining - Emitting a signal indicating a water loss, and / or said water loss Q eccor and at least partially compensating for the

[0069] To achieve gas exchange by diffusion, gas is removed from the blood by passing a sweep or ventilation gas (e.g., dioxygen, air, dry air, humidified air) through the inside of the hollow fibers of the membrane gas exchanger 19 (gas side 202) while blood passes around the hollow fibers (blood side 201).

[0070] Water loss Q in membrane gas exchangers 19 eccor To determine , the control unit 10 is configured to perform calculations via the following formula: i) Q eccor =Q gas ×C saturation_out ×(RH outlet / 100) Where: Q eccor is the blood water loss in the gas exchanger 19, Q gasis the sweep gas flow rate through the gas exchanger 19, C saturation_out is the moisture saturation amount at the gas outlet 19d, RH outlet is the relative humidity at the gas outlet 19d.

[0071] In one embodiment, the gas flow rate Q gas (L / min) may be measured directly, for example, through a flow sensor (not shown) operably connected to the control unit 10. In one embodiment, the gas flow rate Q gas may be a predefined value collected from a storage memory of the control unit 10 or entered by an operator, for example via a keyboard or touch screen, following an operator query.

[0072] In one embodiment, assuming that the gas leaves the membrane gas exchanger 19 at the same temperature as the blood flows through, and knowing the temperature of the blood from the patient "P" or from the extracorporeal blood circuit at the blood inlet 19a of the membrane gas exchanger 19, the water saturation C at the gas outlet 19d is: saturation_out In one embodiment, a temperature sensor is placed at the blood inlet 19a to measure the blood inlet temperature T in is measured. In one embodiment, a temperature sensor may be placed at the gas outlet 19d. In one embodiment, different temperatures are measured (e.g., from the patient "P" or from different points in the extracorporeal blood circuit) and the blood inlet temperature T is calculated by the control unit 10 through a mathematical model that integrates heat loss to the atmosphere and / or liquid exchange. in In one embodiment, a constant default temperature is calculated based on the blood inlet temperature T in The water saturation level C saturation_out is then the blood inlet temperature T in It is calculated as a function of

[0073] In one embodiment, the relative humidity RH at the gas outlet 19d outlet (%) is the type of membrane gas exchanger 19 and the sweep gas flow rate Q gas, which is a value relevant to the type of membrane gas exchanger 19. This is because gas For example, if the type of membrane gas exchanger 19 is unknown, the relative humidity RH outlet is set equal to 100%.

[0074] In one embodiment, the sweep gas entering the gas inlet 19c is humidified, for example through a device arranged between the sweep gas source 20 and the gas inlet 19c. The control unit 10 is therefore configured to perform the calculations taking said humidification into account as well, via the following formula: ii) Q eccor =Q gas ×((C saturation_out ×(RH outlet / 100))-(C saturation_in ×(RH inlet / 100)) Where: Q eccor is the blood water loss in the gas exchanger 19, Q gas is the sweep gas flow rate through the gas exchanger 19, C saturation_out is the moisture saturation amount at the gas outlet 19d, RH outlet is the relative humidity at the gas outlet 19d, C saturation_in is the moisture saturation amount at the gas inlet 19c, RH inlet is the relative humidity at the gas inlet 19c.

[0075] Water saturation amount C at gas inlet 19c saturation_in is the humidification temperature T hum , typically at room temperature T room , which may be measured or calculated, or is a constant default value. inlet is assumed to be equal to 100% if the sweep gas is humidified and 0% if the sweep gas is not humidified.

[0076] In another embodiment, the control unit 10 is configured to also take gas humidification into account and perform the calculation via the following formula: iii) Q eccor =[Q gas ×(α(T in ))]-[Q gas ×(β(T room )) Where: Q gas ×(α(T in ) is the moisture content at the gas outlet 19d, Q gas ×(β(T room ) is the moisture content at the gas inlet 19c, T in is the blood temperature at the blood inlet 19a, T room is room temperature.

[0077] The functions α and β may be derived through calculations and / or experimental testing and may have the following form: 1) α(T in )=(a+b×T in ) 2) β(T room )=d+e×T room Equations 1 and 2 may be derived from air-water saturation tables or from experimental measurements.

[0078] water loss Q eccor Compensation may be achieved by adding water to the extracorporeal blood circuit and / or by reducing the net liquid removal from the extracorporeal blood circuit.

[0079] The control unit 10 calculates the loss Q eccorThe control unit 10 may be configured to issue a signal to alert the operator of the calculated value. The control unit 10 may display such value on a screen of a control panel or may send a signal to a remote device, such as a laptop. This allows for possible medical intervention. The operator may adjust the prescription of the net fluid removal or provide infusion water via a solution, e.g. a glucose solution or an electrolyte / infusion solution, in the extracorporeal blood circuit or directly to the patient "P".

[0080] In one embodiment, the control unit 10 supplies the calculated water loss Q directly to the extracorporeal blood circuit or infusion line 16 via a water source 23, a water line 22, and a water pump 24. eccor In one embodiment, water is pumped into the dialysate line 14 via a water line 22', a water source 23' and a water pump 24'. The control unit 10 is configured to automatically compensate for the calculated blood water loss Q eccor The embodiment is configured to adjust the flow rate of water or solution infused into the extracorporeal blood circuit as a function of the flow rate of the water. The water flow rate is adjusted by adjusting the speed of the water pumps 24, 24'. In these embodiments, the speed of the evacuation pump 13 is not changed relative to standard treatment. Water may be infused as pure water or via a solution, e.g. a glucose solution or an electrolyte / infusion solution. The infusion of said water or solution is not balanced by the evacuation pump 13.

[0081] In one embodiment, when using a glucose solution, the automatic injection may occur directly within the blood circuit of the patient "P". If pure water is injected directly into the extracorporeal blood circuit, the water line 22 terminates in the extracorporeal blood circuit at a mixing site to minimize hemolysis.

[0082] In one embodiment, compensation for the reduction in net fluid removal from the extracorporeal blood circuit is achieved by adjusting the drainage pump 13. The control unit 10 adjusts the calculated blood water loss Q eccorThe controller 10 is configured to automatically adjust, e.g. reduce, the speed of the discharge pump 13 as a function of

[0083] Figure 2 shows a different embodiment of the extracorporeal blood treatment 1. The same reference numbers are used for the same elements as in Figure 1. The extracorporeal blood treatment 1 in Figure 2 does not comprise a blood treatment unit 2, but only a membrane gas exchanger 19. The membrane gas exchanger 19 is the only device in the circuit and the apparatus 1 is configured to provide only ECCO2R therapy (standalone ECCO2R).

[0084] The blood removal line 6 is connected to a blood inlet 19 a of a membrane gas exchanger 19 , and the blood return line 7 is connected to a blood outlet 19 b of the membrane gas exchanger 19 .

[0085] A water line 22 is connected to a source 23 of water in solution, e.g., a glucose solution in a bag, and is connected to the extracorporeal blood circuit between the blood pump 11 and the membrane gas exchanger 19. A water pump 24 controls the flow rate Q of water through the water line 22. water According to an alternative embodiment (not shown), the water line 22 is connected downstream of the membrane gas exchanger 19.

[0086] In this embodiment, the water loss Q eccor The compensation of the blood water loss Q is realized by adding water via the glucose solution directly to the extracorporeal blood circuit via the water line 22. The control unit 10 calculates the calculated blood water loss Q eccor The water flow rate is adjusted by adjusting the speed of the water pump 24.

[0087] Figure 3 shows a further embodiment of extracorporeal blood treatment 1. The same reference numbers are used for the same elements as in Figure 1.

[0088] The extracorporeal blood treatment 1 of FIG. 3 differs from the embodiment of FIG. 1 in that the liquid circuit comprising the dialysate line 14 and the drain line 12 comprises a closed loop comprising a loop pump 100 and connected to the secondary chamber 4, and in that the membrane gas exchanger 19 is located on the liquid circuit rather than on the extracorporeal blood circuit.

[0089] The dialysate line 14 includes a first line 101 connected to a fresh dialysate source, not shown. The drain line 12 includes a second line 102 connected to waste, not shown. A bridging line 103 connects the dialysate line 14 upstream of the first line 101 to the drain line 12 downstream of the second line 102. The dialysate line 14, the drain line 12 and the bridging line 103 form a loop line that exits at the liquid outlet 4b and ends at the liquid inlet 4a. Valves and / or clamps, not shown, allow for different configurations of the liquid circuit. In one configuration, dialysate from a fresh dialysate source flows in the dialysate line 14 into the secondary chamber 4, and used dialysate flows from the secondary chamber 4 into the drain line 12 and then to waste. In one configuration, the dialysate recirculates in a closed loop line.

[0090] In the embodiment of Figure 3, the membrane gas exchanger 19 is placed on the dialysate line 14 between the first line 101 and the liquid inlet 4a. The membrane gas exchanger 19 comprises a liquid side 201 having a liquid inlet 19a and a liquid outlet 19b in liquid communication with the liquid circuit, and a gas side 202 crossed by a sweep gas and having a gas inlet 19c and a gas outlet 19d.

[0091] In this embodiment, carbon dioxide CO2 in the form of dissolved gases and / or bicarbonate is transferred from the blood in the primary chamber 3 to the recirculating dialysate in the secondary chamber 4 of the blood treatment unit 2. Gas is then exchanged in the membrane gas exchanger 19 between the liquid flowing through the liquid side 201 of the membrane gas exchanger 19 and the sweep gas flowing through the gas side 202 of the membrane gas exchanger 19. In the membrane gas exchanger 19, carbon dioxide CO2 is transferred from the recirculating dialysate on the liquid side 201 to the sweep gas on the gas side 202.

[0092] The determination of the water loss in the membrane gas exchanger 19 is substantially the same as disclosed above. The control unit 10 directly supplies the calculated water loss Q eccor 2 and / or into the dialysate lines 14 via water lines 22', water source 23' and water pump 24'.

[0093] While the present invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. 1. An apparatus for extracorporeal treatment of blood, comprising: An extracorporeal blood circuit; a blood pump (11) configured to be coupled to a pump portion of the extracorporeal blood circuit; at least one membrane gas exchanger (19) operably coupled to the extracorporeal blood circuit for exchanging gas with blood flowing therein, the membrane gas exchanger (19) comprising a blood side (201) having a blood inlet (19a) and a blood outlet (19b) in liquid communication with the extracorporeal blood circuit, and a gas side (202) crossed by a sweep gas and having a gas inlet (19c) and a gas outlet (19d); A control unit (10) configured to command the execution of a task, said task comprising at least the following steps: - exchanging gas between the blood flowing through the blood side (201) of the membrane gas exchanger (19) and the sweep gas flowing through the gas side (202) of the membrane gas exchanger (19); - blood water loss (Q) occurring in the membrane gas exchanger (19) due to gas exchange eccor ) to determine - the water loss (Q eccor ) and / or emitting a signal indicative of said water loss (Q eccor ) at least partially compensate and a control unit (10) including:

2. 2. The apparatus of claim 1, wherein determining the blood water loss comprises: - the sweep gas flow rate (Q gas ) and At least the sweep gas flow rate (Q gas ) as a function of the blood water loss (Q eccor and calculating

3. 3. The apparatus of claim 2, wherein determining the blood water loss comprises: - the water saturation at the gas outlet (19d) of the membrane gas exchanger (19) (C saturation_out ) and the water saturation at the gas outlet (19d) (C saturation_out ) as a function of blood water loss (Q eccor and calculating

4. 4. The apparatus of claim 2 or 3, wherein determining the blood water loss comprises: - the water saturation at the gas inlet (19c) of the membrane gas exchanger (19) (C saturation_in ) and - the water saturation at the gas inlet (19d) (C saturation_in ) as a function of blood water loss (Q eccor and calculating

5. 5. The apparatus of claim 2, 3 or 4, wherein determining the blood water loss comprises: - the relative humidity (RH) at the gas outlet (19d) of the membrane gas exchanger (19); outlet ) and - the relative humidity (RH) at the gas inlet (19c) of the membrane gas exchanger (19); inlet ) and - the relative humidity (RH outlet ) and the relative humidity (RH inlet ) as a function of blood water loss (Q eccor and calculating the signal intensity (I) of the signal.

6. 6. The apparatus according to claim 3, wherein the sweep gas flow rate (Q gas ) is - the sweep gas flow rate (Q gas ) directly or indirectly; or - Sweep gas flow rate (Q gas ) collecting a specified value.

7. Where claim 5 depends on claim 3 or 4, or The apparatus according to any one of claims 3 to 6, when claim 6 is dependent on claim 3, 4 or 5, wherein the water saturation (C saturation_out ) is - the blood inlet temperature (T in ) and acquiring the blood inlet temperature (T in ) is measured or calculated or is a constant default value; - the blood inlet temperature (T in The water saturation (C) at the gas outlet (19d) as a function of saturation_out ) The water saturation amount (C saturation_in ) is -Humidification temperature (T hum ) and acquiring the humidification temperature (T hum ) is measured or calculated or is a constant default value; -The humidification temperature (T hum ) at the gas inlet (19c) as a function of the water saturation (C saturation_in and calculating

8. 10. The apparatus according to claim 5 or claim 6 or 7 when dependent on claim 5, wherein the relative humidity (RH outlet ) is - the membrane gas exchanger (19) and the sweep gas flow rate (Q gas ) at the gas outlet (19d) from the type of outlet ) or - the relative humidity (RH outlet ) is assumed to be equal to 100%; The relative humidity (RH inlet ) is - if the sweep gas is humidified, the relative humidity (RH inlet ) is equal to 100%, or - if the sweep gas is not humidified, the relative humidity (RH inlet ) is equal to 0%.

9. 9. The apparatus of claim 1, wherein at least partially compensating for blood water loss comprises adding water to the extracorporeal blood circuit.

10. 10. The apparatus according to claim 1, further comprising a source (23, 23') of water solution connected directly or indirectly to the extracorporeal blood circuit through a water line (22, 22'), a water pump (24, 24') operating on the water line (22, 22'), and wherein at least partially compensating for the water loss comprises injecting water into the extracorporeal blood circuit via the solution.

11. 11. The device according to claim 10, wherein the control unit (10) determines the calculated blood water loss (Q eccor ) as a function of the flow rate (Q water ).

12. 12. The device according to claim 10 or 11, wherein the water line (22) is directly connected to the extracorporeal blood circuit at a connection point located downstream of the blood pump (11).

13. 2. The apparatus of claim 1, wherein determining the blood water loss comprises: - the sweep gas flow rate (Q gas ) and - the blood inlet temperature (T in ) and -Room temperature (T room ) and At least the sweep gas flow rate (Q gas ) and the blood inlet temperature (T in ) and the room temperature (T room ) as a function of the blood water loss (Q eccor and calculating

14. 14. The apparatus of claim 13, wherein determining the blood water loss comprises: - the blood inlet temperature (T in ) as a function of the moisture content at the gas outlet (Q gas-out ) and -The room temperature (T room ) as a function of the moisture content at the gas inlet (Q gas-in ) and the blood water loss (Q ) as the difference between the water percentage at the gas outlet and the water percentage at the gas inlet eccor and calculating

15. 15. The device of claim 14, wherein the blood water loss (Q eccor ) can be calculated using the following formula: Q eccor =[Q gas-out ×(α(T in ))]-[Q gas-in ×(β(T room ))] in accordance with Q gas-out × (α(T in ) is the moisture percentage at the gas outlet (19d), Q gas-in × (β(T room ) is the moisture percentage at the gas inlet (19c), T in is the blood temperature at the blood inlet (19a), T room is the room temperature, The moisture content at the gas outlet (Q gas-out A parameter correlating the water content (Q gas-in ) and said room temperature is derived by experimental testing.

16. 16. The device according to claim 1, wherein the membrane gas exchanger comprises a gas-permeable membrane separating the blood side and the gas side, and wherein carbon dioxide CO 2 The gas exchanged is carbon dioxide (CO 2 ) removed from blood, said gas permeable membrane comprising a plurality of hollow fibers.

17. 1. An apparatus for extracorporeal treatment of blood, comprising: A blood treatment unit (2); an extracorporeal blood circuit coupled to the blood treatment unit (2); a blood pump (11) configured to be coupled to a pump portion of the extracorporeal blood circuit; a fluid circuit connected to the blood treatment unit (2); at least one membrane gas exchanger (19) operably coupled to the extracorporeal blood circuit or liquid circuit for exchanging gas with blood flowing therein or with a liquid flowing therein, the membrane gas exchanger (19) comprising a blood or liquid side (201) having a blood or liquid inlet (19a) and a blood or liquid outlet (19b) in liquid communication with the extracorporeal blood circuit or liquid circuit, and a gas side (202) crossed by a sweep gas and having a gas inlet (19c) and a gas outlet (19d); A control unit (10) configured to command the execution of a task, said task comprising at least the following steps: - exchanging gas between the blood or liquid flowing through the blood or liquid side (201) of the membrane gas exchanger (19) and the sweep gas flowing through the gas side (202) of the membrane gas exchanger (19); - blood or liquid water loss (Q eccor ) to determine - the water loss (Q eccor ) and / or emitting a signal indicative of said water loss (Q eccor ) at least partially compensate and a control unit (10) including:

18. 20. The apparatus of claim 17, wherein determining the blood or liquid water loss comprises: - the sweep gas flow rate (Q gas ) and At least the sweep gas flow rate (Q gas ) as a function of the blood or liquid water loss (Q eccor and calculating

19. 20. The apparatus of claim 18, wherein determining the blood or liquid water loss comprises: - the water saturation at the gas outlet (19d) of the membrane gas exchanger (19) (C saturation_out ) and the water saturation at the gas outlet (19d) (C saturation_out ) as a function of the blood or liquid water loss (Q eccor and calculating

20. 20. The apparatus of claim 18 or 19, wherein determining the blood or liquid water loss comprises: - the water saturation at the gas inlet (19c) of the membrane gas exchanger (19) (C saturation_in ) and - the water saturation at the gas inlet (19d) (C saturation_in ) as a function of the blood or liquid water loss (Q eccor and calculating

21. 21. The apparatus of claim 18, 19 or 20, wherein determining the blood or liquid water loss comprises: - the relative humidity (RH) at the gas outlet (19d) of the membrane gas exchanger (19); outlet ) and - the relative humidity (RH) at the gas inlet (19c) of the membrane gas exchanger (19); inlet ) and - the relative humidity (RH outlet ) and the relative humidity (RH inlet ) as a function of blood or liquid water loss (Q eccor and calculating the signal intensity (I) of the signal.

22. 22. The apparatus according to any one of claims 19 to 21, wherein the sweep gas flow rate (Q gas ) is - the sweep gas flow rate (Q gas ) directly or indirectly; or - Sweep gas flow rate (Q gas ) collecting a specified value.

23. The device according to any one of claims 19 to 22, when claim 21 is dependent on claim 19 or 20 or when claim 22 is dependent on claim 19, 20 or 21, wherein the water saturation (C saturation_out ) is - the blood or liquid inlet temperature (T in ) and acquiring the blood or fluid inlet temperature (T in ) is measured or calculated or is a constant default value; - the blood or liquid inlet temperature (T in The water saturation (C) at the gas outlet (19d) as a function of saturation_out ) The water saturation amount (C saturation_in ) is -Humidification temperature (T hum ) and acquiring the humidification temperature (T hum ) is measured or calculated or is a constant default value; -The humidification temperature (T hum ) at the gas inlet (19c) as a function of the water saturation (C saturation_in and calculating

24. 24. Apparatus according to claim 21 or claim 22 or 23 when dependent on claim 21, wherein the relative humidity (RH outlet ) is - the membrane gas exchanger (19) and the sweep gas flow rate (Q gas ) at the gas outlet (19d) from the type of outlet ) or - the relative humidity (RH outlet ) is assumed to be equal to 100%; The relative humidity (RH inlet ) is - if the sweep gas is humidified, the relative humidity (RH inlet ) is equal to 100%, or - if the sweep gas is not humidified, the relative humidity (RH inlet ) is equal to 0%.

25. 25. The apparatus of claim 17, wherein at least partially compensating for the blood or liquid water loss comprises adding water to the extracorporeal blood circuit or the liquid circuit and / or reducing net liquid removal from the extracorporeal blood circuit.

26. 26. The apparatus of claim 25, wherein the addition of water to the extracorporeal blood circuit or the liquid circuit is not balanced by the evacuation pump.

27. 27. The device according to any one of claims 17 to 26, wherein the blood treatment unit (2) comprises a primary chamber (3) and a secondary chamber (4) separated by a semi-permeable membrane (5), the extracorporeal blood circuit comprises a blood withdrawal line (6) connected to the inlet (3a) of the primary chamber (3) and a blood return line (7) connected to the outlet (3b) of the primary chamber (3), the liquid circuit comprises a drain line (12) connected to the outlet (4b) of the secondary chamber (4) and a drain pump (13) operating on the drain line (12), and the blood or liquid water loss (Q) is controlled by a pump (14) for pumping the blood or liquid water loss (Q) to the extracorporeal blood circuit. eccor ) comprising the control unit configured to adjust the evacuation pump by reducing a pumping speed of the evacuation pump as a function of the calculated blood or liquid water loss.

28. 28. The apparatus according to claim 17, further comprising a source (23, 23') of water solution connected directly or indirectly to the extracorporeal blood circuit through a water line (22, 22'), a water pump (24, 24') operating on the water line (22, 22'), and wherein at least partially compensating for the water loss comprises injecting water into the extracorporeal blood circuit via the solution.

29. 29. The device according to claim 28, wherein the control unit (10) determines the calculated blood or liquid water loss (Q eccor ) as a function of the flow rate (Q water ).

30. 30. The device according to claim 28 or 29, wherein the water line (22) is connected directly to the extracorporeal blood circuit at a connection point located downstream of the blood pump (11).

31. 31. The apparatus according to any one of claims 28 to 30, wherein the blood treatment unit (2) comprises a primary chamber (3) and a secondary chamber (4) separated by a semipermeable membrane (5), the extracorporeal blood circuit comprises a blood removal line (6) connected to an inlet (3a) of the primary chamber (3) and a blood return line (7) connected to an outlet (3b) of the primary chamber (3), a dialysate line (14) is connected to the inlet (4a) of the secondary chamber (4) and to a dialysate source, at least one dialysis pump (15) is coupled or configured to be coupled to a pump portion of the dialysate line (14), and the water line (22') terminates in the dialysate line (14).

32. 32. The apparatus of claim 31, wherein the water line (22') is connected to the dialysate line (14) at a connection point located between the dialysis pump (15) and the blood treatment unit (2).

33. 33. The device according to any one of claims 28 to 32, comprising an injection circuit comprising one or more injection lines (16) of a substitution fluid connected to the extracorporeal blood circuit and at least one injection pump (18) coupled or configured to be coupled to pump portions of the injection lines (16), the water line (22) terminating in at least one of the injection lines (16).

34. 34. Device according to any one of claims 31 to 33, in at least one configuration, the liquid circuit presents a closed loop connected to the secondary chamber (4).

35. 20. The apparatus of claim 17, wherein determining the blood or liquid water loss comprises: - the sweep gas flow rate (Q gas ) and - the blood or liquid inlet temperature (T in ) and -Room temperature (T room ) and At least the sweep gas flow rate (Q gas ) and the blood or fluid inlet temperature (T in ) and the room temperature (T room ) as a function of the blood or liquid water loss (Q eccor and calculating

36. 36. The apparatus of claim 35, wherein determining the blood or liquid water loss comprises: - the blood or liquid inlet temperature (T in ) as a function of the moisture content at the gas outlet (Q gas-out ) and -The room temperature (T room ) as a function of the moisture content at the gas inlet (Q gas-in ) and the blood or liquid water loss (Q ) as the difference between the water percentage at the gas outlet and the water percentage at the gas inlet eccor and calculating

37. 37. The device of claim 36, wherein the blood or liquid water loss (Q eccor ) can be calculated using the following formula: Q eccor =[Q gas-out ×(α(T in ))]-[Q gas-in ×(β(T room ))] in accordance with Q gas-out × (α(T in ) is the moisture percentage at the gas outlet (19d), Q gas-in × (β (T room ) is the moisture percentage at the gas inlet (19c), T in is the blood temperature at the blood inlet (19a), T room is the room temperature, The moisture content at the gas outlet (Q gas-out A parameter correlating the moisture content (Q ) at the gas inlet with the blood or liquid inlet temperature is derived through calculation. gas-in ) and said room temperature is derived by experimental testing.

38. 38. The device according to any one of claims 17 to 37, wherein the membrane gas exchanger comprises a gas permeable membrane separating the blood or liquid side from a gas side, and wherein carbon dioxide CO 2 The gas exchanged is carbon dioxide (CO 2 ) removed from blood or fluid, said gas permeable membrane comprising a plurality of hollow fibers.

39. 39. The apparatus of any one of claims 17 to 38, wherein a sweep gas source is connected to the gas inlet for supplying a sweep gas through the gas side of the membrane gas exchanger, the sweep gas being a dry gas or a humidified gas.

40. 40. The apparatus of claim 39, wherein a device for humidifying the sweep gas is disposed between the sweep gas source and the gas inlet.

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