Method for influencing the pressure within a heating bag during a medical treatment and medical apparatus

Abstract

A method for controlling or regulating the pressure, which prevails within a heating bag of a tubing system used for the treatment, wherein the method encompasses the steps: Determining the pressure; comparing the determined pressure with a reference pressure or detecting its state with respect to a reference pressure range and changing a treatment parameter of the treatment of the patient or suggesting a correction of the treatment parameter in case the determined pressure is below or above, respectively, the reference pressure or outside the reference pressure range.

Claims

1. A method for regulating or controlling, during a treatment of blood of a patient, a pressure which prevails within a heating bag of a tubing system used for the treatment, the method comprising: determining the pressure; comparing the determined pressure to a reference pressure or detecting the determined pressure's state with respect to a reference pressure range; and avoiding a collapse of the heating bag by changing at least one treatment parameter of the treatment of the patient or suggesting a correction or change of the at least one treatment parameter when the determined pressure is below or above the reference pressure, or is outside of the reference pressure range.

2. The method according to claim 1, wherein determining the pressure is achieved by measuring with or via a pressure sensor.

3. The method according to claim 1, wherein the at least one treatment parameter of the treatment is a substitution flow or an ultrafiltration rate.

4. The method according to claim 2, wherein the at least one treatment parameter of the treatment is a substitution flow or an ultrafiltration rate.

5. The method according to claim 3, wherein the substitution flow is reduced such that or until the determined pressure is above or below the reference pressure, or again reaches within the reference pressure range.

6. The method according to claim 4, wherein the substitution flow is reduced such that or until the determined pressure is above or below the reference pressure, or again reaches within the reference pressure range.

7. The method according to claim 1, wherein the reference pressure is ambient pressure.

8. The method according to claim 5, wherein the reference pressure is ambient pressure.

9. The method according to claim 1, wherein the pressure is determined by a pressure detector arranged in a dialysis fluid line of the tubing system downstream of a dialysis fluid pump.

10. The method according to claim 7, wherein the pressure is determined by a pressure detector arranged in a dialysis fluid line of the tubing system downstream of a dialysis fluid pump.

11. The method according to claim 1, further comprising effecting or manipulating the determined pressure by a device arranged upstream of a dialyzer and downstream of a heating device, wherein the device is a valve, a throttle or an orifice.

12. The method according to claim 7, further comprising effecting or manipulating the determined pressure by a device arranged upstream of a dialyzer and downstream of a heating device, wherein the device is a valve, a throttle or an orifice.

13. The method according to claim 1, wherein the pressure is determined by a pressure detector arranged in a substituate line of the tubing system downstream of a substituate pump.

14. The method according to claim 7, wherein the pressure is determined by a pressure detector arranged in a substituate line of the tubing system downstream of a substituate pump.

15. The method according to claim 1, wherein the heating bag contains dialysis fluid or substituate.

16. The method according to claim 9, wherein the heating bag contains dialysis fluid or substituate.

17. A medical apparatus comprising a control or regulating device for controlling or regulating, during a treatment of blood of a patient, a pressure which prevails within a heating bag of a tubing system used for the treatment, the control or regulating device configured to: determine the pressure; compare the determined pressure to a reference pressure or detect the determined pressure's state with respect to a reference pressure range; and avoid a collapse of the heating bag by changing at least one treatment parameter of the treatment or suggesting a correction or change of the at least one treatment parameter when the determined pressure is below or above the reference pressure, or is outside of the reference pressure range.

18. The medical apparatus according to claim 17, wherein the medical apparatus is a blood purification device or a dialysis device.

19. An extracorporeal blood treatment method comprising: determining a pressure within a medical fluid heating bag; comparing the determined pressure to a reference pressure or a reference pressure range; and avoiding a collapse of the heating bag by changing at least one treatment parameter of the extracorporeal blood treatment method of the patient or suggesting a change of the at least one treatment parameter when the determined pressure is below or above the reference pressure or is outside of the reference pressure range.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows schematically a medical apparatus according to the present invention for the dialysis with or in an extracorporeal blood circuit and a tubing system in a first embodiment.

(2) FIG. 2 shows schematically a medical apparatus according to the present invention for the dialysis with or in an extracorporeal blood circuit and a tubing system in a second embodiment.

(3) FIG. 3 shows schematically a medical apparatus according to the present invention for the dialysis with or in an extracorporeal blood circuit and a tubing system in a third embodiment.

(4) FIG. 4 shows schematically a medical apparatus according to the present invention for the dialysis with or in an extracorporeal blood circuit and a tubing system in a fourth embodiment.

(5) FIG. 5 shows schematically strongly simplified a first development according to the present invention of a section of the medical apparatus.

(6) FIG. 6 shows schematically strongly simplified a second development according to the present invention of a section of the medical apparatus.

DETAILED DESCRIPTION

(7) FIG. 1 shows a tubing system 200 with a dialysis fluid tubing system 300 and a substituate tubing system 500 in a first embodiment as part of a medical apparatus 600 according to the present invention which is herein, purely exemplarily, a treatment system for a dialysis. The medical apparatus 600 further comprises a blood circuit 400 (represented herein as a section), furthermore a dialyzer 11, which is flown by two fluid systems (blood and dialysis fluid) for exchange of substances.

(8) The dialysis fluid tubing system 300 which can be embodied as a single use tubing system (disposable) is being filled with dialysis fluid from a bag 9. The dialysis fluid is conveyed along the dialysis fluid tubing system 300 by a pump 13 which, by way of example only, is embodied as a roller pump. The dialysis fluid from bag 9 may flow into a heating device 14 which is arranged downstream of pump 13, that is, on the pressure side of pump 13, by gravity or by aspiration of the pump, or both. The heating device 14 shown in the figures isby way of exampleembodied as a device comprising at least a heating bag 15 and heating rods or heating spindles 17 for which reason it is herein also called a bag heater. The dialysis fluid is heated inside the heating bag 15. For ensuring that heat is transferred from the heating device 14 or the heating spindles 17 to the heating bag 15 it is helpful or may be even necessary that compared to the atmosphere at least a reference pressure, usually or preferably a positive, preferably determinable, inner pressure of the dialysis fluid prevails inside the heating bag 15. This way, the wall of heating bag 15 nestles or adjusts to the heating spindles 17, this enables or promotes the heat transfer. In other words, herein exemplarily, by a positive inside pressure, a collapsing of the heating bag 15 and a deterioration or interruption of the heat transfer is avoided.

(9) Purely optionally, a valve 1 is arranged further downstream of the pump or dialysis fluid pump 13 and downstream of the heating device 14. In this embodiment example the valve 1 is also integrated into the tubing system 300. Therefore, FIG. 1 shows no tubing adapter, which is also encompassed by the present invention. Valve 1, being integrated as is shown here needs, therefore, no tubing couplings. Alternatively, the valve 1, being part of a tubing adapter, may be interconnected with the tubing system 200.

(10) Valve 1 is arranged within the tubing system 300 such that it closes if the pressure upstream of valve 1, that is between valve 1 and heating device 14 or heating bag 15 is too low. By said closing, it is avoided that a pressure which is too low and which prevails downstream of valve 1 propagates upstream of valve 1 and into the heating bag 15 and possibly results in a negative pressure (related to the atmosphere) or in an inside pressure that is lower than desired. As already discussed above, a positive pressure inside the heating bag 15 is helpful for establishing or securing the desired or expected heat transfer.

(11) In certain exemplary embodiments according to the present invention, the opening pressure is between 5 and 1000 hPa, preferably between 50 and 400 hPa, particularly preferably between 100 and 350 hPa. That is, the inner pressure or inside pressure of the heating bag 15 must be at least as high as this value or must exceed a pressure downstream of the valve by at least this value for the valve 1 to open, if the flow loss occurring in the tubing section between the heating bag 15 and the valve 1 are not taken into account. In other words, the pressure upstream of valve 1 must be at least that high (between 5 am 1000 hPa, preferably between 50 and 400 hPa, particularly preferably between 100 and 350 hPa) or exceed by this value to overcome the opening pressure of valve 1.

(12) A lower pressure downstream of valve 1, and, in consequence, evacuating or sucking dry of the dialysis fluid further upstream up to the heating bag 15 may in practice have several reasons.

(13) The medical device 600 (also referred to as a treatment system) is purely exemplarily embodied for dialysis, in this exemplary embodiment especially embodied for the continuous veno-venous hemodiafiltration (a combination of hemofiltration and hemodialysis), short CVV-HDF.

(14) Blood is taken from the patient by an arterial connector 19 or an arterial line of the extracorporeal blood circuit 400. A stop-cock 21 is arranged downstream of the arterial connector 19. Downstream of the latter the arterial pressure is measured by a pressure sensor 23; further downstream there is a blood pump 13. Between the blood pump 13 and the connector of the arterial line for connecting the arterial line with the dialyzer 11 the hemofiltration pressure or the pre-filter pressure is measured by a pressure sensor 25. Downstream of the pressure sensor 25 heparin is administered to the blood for anticoagulation at an admission port 27.

(15) Within the dialyzer 11 substances are exchanged with the dialysis fluid of the tubing system 300 which leaves the dialyzer 11 as dialysate. This will be further explained below.

(16) Downstream of the dialyzer 11, the blood flows in a venous drop chamber 29 in which the venous pressure is measured by a pressure sensor 31. A stop-cock 33 is arranged downstream thereof. The blood is returned into the vessels of the patient by a venous connector 35.

(17) The substituate tubing system 500 serves to partly substitute the fluid volume which was removed by filtration or ultrafiltration within the dialyzer 11 during treatment. To this end, substituate fluid from a bag 9 is used. The substituate is conveyed within the substituate tubing system 500 by a substituate pump 13 into a heating bag 15 where it is heated before it is fed into the blood circuit 400.

(18) The dialysis fluid tubing system 300 upstream of the dialyzer 11 has already been explained with reference to FIG. 2. The filtrate pressure is measured downstream of the dialyzer 11 by a pressure sensor 37; further downstream the dialysate istogether with the filtrateconveyed into a collecting bag 39 by a pump 13 (referred to also as dialysate or filtrate pump) or disposed.

(19) In the following, reasons for a low pressure downstream of valve 1 are discussed.

(20) A lower pressure (when compared to the atmosphere) downstream of valve 1 which would possibly result in evacuating or sucking dry of the heating bag 15 if there was no valve 1 may be caused by, for example, deposit on the filter membrane of the dialyzer 11 (on the membrane side of the blood circuit 400; for example by blood that starts clotting). This results in a decrease of the permeability of the filter membrane in the dialyzer and also to an increased transmembrane pressure TMP.

(21) Regardless of this phenomenon using filter membranes of low permeability may also result in this low pressure problem on the dialysis side of the dialyzer 11 (the same effect as with deposit on the membrane may occur here). Thus, a low permeability results in a high TMP for achieving a desired or requested exchange of substances in the dialyzer 11. Hence, when using filter membrane having low permeability, the dialysis fluid tubing system 300 may be used in order to avoid a marked negative pressure in the heating bag 15, thus, ensuring an optimal, desired or expected heat transfer from the heating housing to the heating bag 15.

(22) A pressure on the dialysis side which is possibly too low for the needs of the heating bag occurs particularly during dialysis treatments which are performed or executed by means of the continuous veno-venous hemodiafiltration (CW-HDF). In this case, also the substituate volume added by the machine through the substituate tubing system 500 over the filter membrane of the dialyzer 11 must be withdrawn from the patient in addition to the fluid which should be withdrawn from the patient by the dialyzer 11. This requires high filtration flow rates and a correspondingly high pressure gradient over the filter membrane, i.e., a high transmembrane pressure TMP.

(23) The pressure reference point for the area around the filter membrane of the dialyzer 11 is located in the area of the venous connector 35. The pressure reference point for the dialysis side is the pressure sensor 37. From there, the pressure of the dialysis side of the filter membrane (in the dialysis fluid tubing system 300) may be tracked back by considering pressure differences caused by flow and by hydrostatic pressure differences. It is readily understood that with a sufficiently high TMP a pressure below atmosphere may prevail within the heating bag 15 and that the heating bag may collapse if this is not avoided by, for example, using the tubing adapter or the dialysis fluid tubing system 300.

(24) A control or regulating device 700 is indicated in the figures purely schematically. In practice, it is connected in signal communication to the corresponding components such as pressure detectors, ultrafiltration pumps or substituate pumps.

(25) FIG. 1 shows an exemplary arrangement in which the valve 1 is provided. With such an arrangement, the pressure may beas one possibility out of many for determining the/a pressuredetermined by an optionally provided pressure detector 41, which is purely exemplarily arranged in a dialysis fluid line 43.

(26) In case the valve 1 is not provided, then pressure may also be determined by the pressure sensor 37.

(27) Determining the pressure by the pressure detector 41 has the additional advantage that increases of pressure in the heating bag 15 may be recognized or detected. Such increases of pressure may, for example, occur due to a closed clamp which has been unintentionally placed on a dialysate line downstream of the dialyzer 11 or has not been removed off the latter at the beginning of the treatment. Thus, the heating bag 15 may be protected against too-high pressure and therefore against damage, for example by stopping the dialysis fluid pump 13. Such stopping may be carried out automatically. A corresponding alarm may alternatively or additionally be issued. The herein described determining of pressure and the advantages related thereto are also possible or achievable in other sections of the tubing system 200, as it is purely exemplarily shown in FIG. 4 for the substituate tubing system 500 with a pressure detector 45 and a valve 49.

(28) It is pointed out that the embodiments according to the present invention shown in the figures and/or described supra are not at all limited in their use to tubing systems which are used in the dialysis. Each other treatment method may equally profit from the present invention.

(29) In the figures, an addition of substituate in post-dilution (i.e., downstream of the dialyzer 11) is illustrated. The dashed line shows, respectively, that an addition also in pre-dilution (i.e., upstream of the dialyzer 11) is possible and may be provided.

(30) FIG. 2 shows schematically a medical apparatus according to the present invention with a tubing system in a second embodiment.

(31) In FIG. 2, the dialysis fluid tubing system 300 comprises a pressure detector 41, which is arranged in a dialysis fluid line 43. FIG. 2 does not show the purely optional valve 1 of FIG. 1. Nevertheless, it might also have been provided there.

(32) FIG. 3 shows schematically a medical apparatus according to the present invention with a tubing system in a third embodiment. In FIG. 3, the dialysis fluid tubing system 300 does not comprise the optional pressure detector 41.

(33) FIG. 3 illustrates one of the possible functionalities of the control and regulating device 700. With the regulation shown in FIG. 3, which may also be a controlling, the device 700 is then used to effect the substituate pump 13, when the pressure sensor 37 detects or determines a pressure downstream of the dialyzer 11, herein the filtrate pressure p_filt, which is, for example, below the reference pressure. Such effect decreases the substituate flow Q_sub, for example during a CVV-HDF treatment, until or such that the filtrate pressure p_filt exceeds or rises above the reference pressure. In the example of FIG. 3, the reference pressure corresponds to the ambient pressure. In case the filtrate pressure p_filt exceeds the reference pressure or ambient pressure again, the heating bag will not collapse (anymore).

(34) It is additionally pointed out that the aforementioned, performed regulation/control is arranged to maintain or keep the adjusted or set total decrease in weight which results from the balance between the weight of the fluid being withdrawn from the patient and the weight of the fluid being given to the patient by substitution untouched or unchanged. In case of a threat of the heating bag 15 collapsing, then the flow rate of the filtrate pump 13 must be reduced to counteract a collapse. As a result of such decrease, there will be less filtering out of filtrate through the dialyzer membrane. Hence, the rate of the decrease of weight does not correspond to what has been adjusted by the doctor, it is too low. Less fluid as a whole is withdrawn out of the patient than desired. Said fluid is compensated in that the substituate rate is correspondingly reduced as well by the substituate pump 13. The fluid balance being based on the ultrafiltration rate is thus ensured by reducing both the ultrafiltration and the addition of substituate. This is indicated in FIG. 3 with the arrows.

(35) FIG. 4 shows schematically a medical apparatus according to the present invention for the dialysis with one tubing system in a fourth embodiment.

(36) In FIG. 4, there is a likewise purely optional pressure detector 45 of a substituate line 47 downstream of the substituate pump 13 instead of the optional dialysis fluid line 43. The embodiment of FIG. 4 comprises in addition a valve 49 downstream of the heating bag 15. Valve 49 may correspond to valve 1 of FIGS. 1 and 3 both in function and in structure.

(37) The provision of the pressure detector 45 advantageously allows a detection of an over pressure or of an inadmissible high pressure in the heating bag 15. Therefore, it is possible to avoid an explosion of the heating bag 15 by taking appropriate measures like stopping or reducing or decreasing the corresponding pump.

(38) It is pointed out that embodiments according to the present invention may separately comprise a valve 1, a valve 49, a pressure detector 41, a pressure detector 45 and/or a pressure sensor 37. The control or regulating device 700 is suitably configured to respectively influence at least the pumps 13, 13 or 13 as well as optionally on the valve 1, 49when being intentionally adjustable by means of an actuator, e.g., by opening and closingin order to effect a change of the respective, monitored or detected pressure in a desired range or beyond a threshold.

(39) FIG. 5 shows schematically, strongly simplified a first development according to the present invention of a section of the medical apparatus.

(40) In this embodiment, the containers 9 and 9 of the previous figures are combined to one container 9a. The dialysis fluid pump 13 and the substituate pump 13 are supplied together by the container 9a, for example through a common line 51.

(41) The design according to the present invention of FIG. 5, which, unlike the designs described in the previous figures, provides a common supply to or towards dialysis fluid pump 13 and substituate 13 from only, in any case however from one common source, may complement each feature combination or embodiment disclosed herein. Such design is thus combinable with each of the herein made embodiments and may thereby replace the separate supply from separate sources regardless of all other details of the design.

(42) Furthermore, a connecting line 52 between the supply line of the dialysis fluid pump 13 and the supply line of the subsituate pump 13 is shown in FIG. 5.

(43) FIG. 6 shows schematically, strongly simplified a second development according to the present invention of a section of the medical apparatus.

(44) The design according to the present invention of FIG. 6, which, unlike the designs described in the previous figures, provides a Y-piece 53 for the common supply of the dialysis fluid pump 13 and substivate pump 13, however from separate sources, may as well complement each feature combination or embodiment disclosed herein. Such design is thus combinable with each of the herein made embodiments and may thereby replace the separate supply from separate supply lines regardless of all other details of the design.

(45) In FIGS. 5 and 6 the supply lines for substituate and dialysis fluid are in fluid communication via the connecting line 52. Also this design may likewise complement each feature combination or embodiment disclosed herein, regardless of the other features.

(46) TABLE-US-00001 List of Reference Numerals Reference Description 200 tubing system 300 dialysis fluid tubing system 400 blood circuit 500 subsituate tubing system 600 medical apparatus 700 control and regulating device 1 check valve, valve 9, 9 bag 9a container 11 dialyzer 13 dialysis fluid pump 13 blood pump 13 substituate pump 13 dialysate pump 14 heating device 15, 15 heating bag 17 heating spindle or coil, heating rods 19 arterial connector 21 stop-cock, arterial 23 arterial pressure sensor 25 pressure sensor for hemofiltration pressure or pre-filter pressure 27 admission port for heparin 29 venous drop chamber 31 venous pressure sensor 33 stop-cock, venous 35 venous connector 37 pressure sensor for filtrate pressure 39 collecting container 41 pressure detector 43 dialysis fluid line 45 pressure detector 47 substituate line 49 check valve, valve 51 common line 52 connecting line between the pumps 53 Y-piece