APPARATUS AND METHOD FOR DETERMINING THE STATIC PATIENT PRESSURE

Abstract

The present invention relates to an apparatus for determining the static patient pressure, wherein the apparatus comprises a pump in communication with a patient line for conveying a dialysis solution into the abdomen of the patient, and blocking means, in particular a valve by which the patient line is blockable, wherein the apparatus has a pressure chamber that is in fluid communication with the patient line with an open blocking element, with a pressure measurement device furthermore being provided that is arranged such that it measures the pressure in the pressure chamber or a pressure correlated with it; and wherein the apparatus comprises a control unit that is configured such that it effects a pressure build-up in the pressure chamber to a measurement pressure in a first step and opens the blocking element in a second step so that the patient line or a part section thereof is acted on by the measurement pressure of the pressure chamber and with the apparatus having an evaluation unit that evaluates the measured pressure after the opening of the blocking element.

Claims

1. An apparatus for determining the static patient pressure of a peritoneal dialysis patient, wherein the apparatus comprises a patient line, a pump in communication with the patient line for conveying a dialysis solution into the abdomen of the patient, and blocking means, in particular a valve by which the patient line is blockable, characterized in that the apparatus has a pressure chamber that is in fluid communication with the patient line with an open blocking element, with a pressure measurement device furthermore being provided that is arranged such that it measures the pressure in the pressure chamber or a pressure correlated with it; and in that the apparatus comprises a control unit that is configured such that it effects a pressure build-up in the pressure chamber to a measurement pressure in a first step and opens the blocking element in a second step so that the patient line or a part section thereof is acted on by the measurement pressure of the pressure chamber and with the apparatus having an evaluation unit that evaluates the measured pressure after the opening of the blocking element.

2. An apparatus in accordance with claim 1, characterized in that the control unit is configured such that the measurement pressure built up in the pressure chamber is larger than the suction pressure in the patient line after the opening of the blocking element.

3. An apparatus in accordance with claim 1, characterized in that the pressure chamber is arranged between the pump and the patient line; or in that the pressure chamber forms a component of the pump.

4. An apparatus in accordance with claim 1, characterized in that the pressure chamber is formed by a part of a disposable cassette.

5. An apparatus in accordance with claim 4, characterized in that the cassette comprises the pump and/or the pressure chamber and/or means for controlling the dialysis flow and/or blocking means for suppressing the dialyzate flow.

6. An apparatus in accordance with claim 1, characterized in that the evaluation unit is configured to compare the pressure measured after the opening of the blocking element with a reference pressure or with the measurement pressure and, based on this, to draw a conclusion on the state of the patient line.

7. An apparatus in accordance with claim 1, characterized in that the evaluation unit is configured to draw a conclusion on a partly or completely closed patient line when the difference between the measurement pressure built up in the pressure chamber and the pressure measured after the opening of the blocking element and/or when the speed of the change of the measured pressure does not exceed a limit value.

8. An apparatus in accordance with claim 1, characterized in that the evaluation unit is configured such that it sets the suction pressure of the pump in dependence on the measured pressure or on the time development of the measured pressure.

9. An apparatus in accordance with claim 1, characterized in that the evaluation unit is configured such that it outputs an alarm when it is found that the patient line is not free.

10. An apparatus in accordance with claim 1, characterized in that the evaluation unit is configured such that it carries out a localization as to the position at which a constriction or a closure of the patient line is present based on the difference between the measurement pressure built up in the pressure chamber and the pressure measured after opening the blocking element and/or based on the speed of the change of the measured pressure.

11. A peritoneal dialysis machine comprising at least one apparatus in accordance with claim 1.

12. A method of determining the static patient pressure, wherein the method comprises the following steps: a. Building up a measurement pressure in a pressure chamber while the patient line is separated from the pressure chamber by a blocking means; b. Opening the blocking means; and c. Measuring the pressure and/or the pressure change after the opening of the blocking means, with the pressure in the pressure chamber or a pressure correlated therewith being measured; and d. Evaluating the pressure and/or pressure change measured in accordance with step c).

13. A method of determining the static patient pressure, wherein the method comprises the following steps: a. Building up a measurement pressure in a pressure chamber while the patient line is separated from the pressure chamber by a blocking means; b. Opening the blocking means; and c. Measuring the pressure and/or the pressure change after the opening of the blocking means, with the pressure in the pressure chamber or a pressure correlated therewith being measured; and d. Evaluating the pressure and/or pressure change measured in accordance with step c), characterized in that the method is carried out by means of an apparatus in accordance with claim 1.

14. A method in accordance with claim 1, characterized in that a conclusion is drawn on a partly or completely closed patient line when the difference between the measurement pressure built up in the pressure chamber and the pressure measured after the opening of the blocking element and/or when the speed of the change of the measured pressure falls below a limit value or does not exceed a limit value.

15. A method in accordance with claim 1, characterized in that the suction pressure of the pump is set in dependence on the measured pressure or on the time development of the measured pressure.

16. A method of determining the static patient pressure, wherein the method comprises the following steps: a. Building up a measurement pressure in a pressure chamber while the patient line is separated from the pressure chamber by a blocking means; b. Opening the blocking means; and c. Measuring the pressure and/or the pressure change after the opening of the blocking means, with the pressure in the pressure chamber or a pressure correlated therewith being measured; and d. Evaluating the pressure and/or pressure change measured in accordance with step, c), characterized in that the method is carried out by means of a peritoneal dialysis machine in accordance with claim 11.

Description

[0047] Further details and advantages of the invention will be explained in more detail with reference to an embodiment shown in the drawing.

[0048] The only FIGURE shows a schematic flowchart of a peritoneal dialysis machine in accordance with the present invention.

[0049] Reference symbol D1 denotes a bag or another container containing fresh dialysis solution. It is in fluid communication with the line 10. The line 10 is blockable by the valve V14 and is in communication with the suction lines of the membrane pumps 1 and 2 via a branch. As can be seen from the FIGURE, blocking valves V1 and V3 are located in the suction lines of the pumps.

[0050] Reference symbols P1 and P2 denote pressure sensors that are arranged to measure the respective pressure in the hydraulic medium of the membrane pumps 1 and 2.

[0051] Blocking valves V2 and V4 are arranged in the pressure lines of the pumps 1 and 2.

[0052] The valves V1 to V4 are preferably controlled so that the pumps 1 and 2 are operated alternately in operation of the machine so that a continuous flow of dialysis solution is achieved.

[0053] Reference numeral 20 denotes the patient line in which the blocking valve V5 is located. Fresh dialyzate moves to the patient and consumed dialyzate moves from the patient P to the drainage bag or other drainage container D2 via the patient line 20. The valve V10 is located in the drainage line 30.

[0054] The pumps 1, 2 have pressure chambers K1, K2. They can be components of a cassette that can be formed as a disposable. The pressure pick-up or the pressure sensor P3 is located between the pressure chamber K1, K2 and the blocking valve V5.

[0055] It is emphasized at this point that the pressure sensor P3 is optional. The invention can generally also only be implemented using the pressure sensor and/or sensors P1 and/or P2.

[0056] The pressure measurement could also conversely only take place with the pressure sensor P3 so that the invention is only implemented with this measurement value and not while using the pressure values of the sensors P1 and/or P2.

[0057] It is also covered by the invention that the values determined at the hydraulic side (pressure measurement P1/P2) and cumulatively the values determined at the dialyzate side (pressure measurement P3) are used as part of the invention.

[0058] Both an alternative and a cumulative arrangement of sensors at the hydraulic side and/or at the dialyzate side or their use as part of the present invention are thus conceivable and covered by the invention within the framework of the present invention.

[0059] An increased positive pressure is built up by means of the pumps 1 or 2 or by means of both pumps 1, 2 in the pressure chamber K1, K2 before the calibration of the static patient pressure. The valve V5 is closed here. After the build-up of the pressure (measurement pressure) in the pressure chamber K1, K2, the valve V5 in the patient line is opened and the pressure and/or its time development is/are measured by means of the pressure sensor P3.

[0060] If the patient line 20 is free, the built-up measurement pressure in the patient line 20 and in the abdomen of the patient P equalizes. The static patient pressure is adopted that reflects the vertical difference of the patient from the dialysis machine.

[0061] If the patient line 20 is, however, not free, but rather closed, a pressure change is optionally admittedly also measured, but it is a falsified measurement value here that would have the result that too high a patient position is determined because the measurement pressure only dropsif at allby a relatively small amount. The energy amount of the pump is reduced.

[0062] This behavior causes the suction pressure to increase with a closed patient line and results in a more gentle start-up behavior.

[0063] Said positive measurement pressure in the chamber K1, K2 should be selected such that the applied suction pressure is superposed. In this respect, the volume relationships of the hose set to the patient line and the applied suction pressure have to be taken into account.

[0064] One or both of the pumps shown can be used to build up the measurement pressure.

[0065] If the patient is still filled with dialysis solution when the method is carried out, no volume displacement takes place to carry out the measurement method in accordance with the invention. A separate patient line check is no longer necessary since the system corrects itself. The invention is, however, generally also usable in a condition in which the patient is partly or completely emptied.

[0066] A preferred procedure of the method is as follows:

[0067] The peritoneal dialysis machine is at the start or before a start-up phase, i.e. before the emptying of the patient.

[0068] The hydraulic pumps 1, 2 are operated into a pump region which allows an excess pressure to be built up in the chamber K1 and/or K2 without being exposed to the influence range of the pump membrane.

[0069] The pressure in the total cassette K is raised into an excess pressure range, e.g. to a pressure value in the range from 50 mbar to 400 mbar, preferably in the range from 200 mbar to 300 mbar, and, for example, to a pressure value of 250 mbar.

[0070] A flow path between the cassette K and the patient line 20 is established by opening the valve V5 and the pressure is measured.

[0071] This can take place via the pressure sensors P1 or P2 arranged at the hydraulic side or also by a pressure measurement in the dialysis solution, for example by means of the pressure sensor P3. As stated above, the pressure measurement can take place alternatively or cumulatively by means of the pressure sensors at the hydraulic side or by means of the pressure sensors at the dialyzate side.

[0072] The pressure now adopted maps the patient position i.e. represents the static patient pressure.

[0073] The value determined is supplied to an evaluation unit, not shown.

[0074] The valve V10 of the line 30 and the suction valves V1 and V3 are closed during the method.

[0075] If the patient line 20 is free, the pressure in the chambers K1, K2 will propagate via the patient line 20 with open valves V2, V4, and V5 into the abdomen of the patient. The pressure at the sensors P1, P2, P3 drops.

[0076] If the patient line 20 is not free, but clogged, the pressure with open valves V2, V4 and V5 in the chambers K2, K2 will only propagate into the patient line 20 up to the kink point or to the point of the clogging. The pressure at the sensors P1, P2, P3 likewise drops, but only by a smaller amount than with a free patient line.

[0077] If the patient line is not completely clogged or kinked, but only the free flow cross-section, a slowed down pressure reduction occurs with respect to a free patient line.

[0078] The evaluation unit detects the pressure value after the opening of the valve V5 or the pressure development after the opening of the valve. A calculation algorithm of the evaluation unit determines whether the patient line is partly or completely blocked or clogged and if so, where this is the case.

[0079] Based on the evaluation of the evaluation unit, the power of the pumps can be correspondingly adapted because a partly clogged patient line has a larger flow resistance than a free patient line and thus a greater suction power.

[0080] If the patient line is partly or completely clogged, an alarm can be output that makes the user aware of it.