A method for checking the conveying accuracy of conveying devices of a medical treatment apparatus, and apparatuses

Abstract

The present invention relates to a method for checking the conveying accuracy of conveying devices of a blood treatment apparatus. It further relates to a blood treatment apparatus with a control device and/or closed-loop control device, through which the method is effected, a digital storage medium, a computer program product, and a computer program.

Claims

1-28. (canceled)

29. A method for checking or monitoring conveying or conveyance accuracy of conveying devices of a group of conveying devices, the group consisting of: a first conveying device, a second conveying device, and a third conveying device of a blood treatment apparatus for the extracorporeal blood treatment, the method comprising: a) providing a completely liquid-filled receptacle which is in fluid communication with every conveying device of the group of conveying devices; b) setting a predetermined initial pressure in the receptacle or measuring the pressure prevailing therein by a first pressure measurement and defining the measured pressure as an initial pressure; c) actuating one conveying device of the group of conveying devices such that the one conveying device accomplishes a target conveying activity required with respect to the one conveying device in order to convey the predetermined liquid volume out of the receptacle; and d) measuring, in a second pressure measurement, the pressure prevailing in the receptacle after the target conveying activity of the one conveying device has been completed, wherein the second pressure measurement is an end pressure, wherein the sequence of steps a) to d) is carried out successively for each conveying device of the group of conveying devices, whereby for conveying by the first conveying device there are determined a first end pressure and a first pressure difference between the initial pressure and the first end pressure, and/or a first compliance, whereby for conveying by the second conveying device there is determined a second end pressure and a second pressure difference between the initial pressure and the second end pressure, and/or a second compliance, and whereby for conveying by the third conveying device there is determined a third end pressure and a third pressure difference between the initial pressure and the third end pressure, and/or a third compliance, the method further comprising evaluating: (i) at least the first end pressure, the second end pressure and the third end pressure, or (ii) at least the first pressure difference, the second pressure difference and the third pressure difference, or (iii) at least the first compliance, the second compliance and the third compliance, with regard to deviation of an actual conveying activity of the first, second and/or third conveying device from the respectively requested target conveying activity.

30. The method according to claim 29, wherein the evaluation is carried out while obtaining a measure for the deviation of the actual conveying activity of the first, second and/or third conveying device from the respectively requested target conveying activity.

31. The method according to claim 29, wherein the evaluation is carried out by, or consists of, comparing the first, second and third end pressure, or the first, second and third pressure difference, or the first, second and third compliance, with each other.

32. The method according to claim 29, wherein the evaluation further comprises: determining whether the first end pressure, the second end pressure as well as the third end pressure, and/or whether the first pressure difference, the second pressure difference as well as the third pressure difference, and/or whether the first compliance, the second compliance as well as the third compliance, are within predetermined limits, exceed or fall below a threshold, exceed a minimum value and/or do not exceed a maximum value, and/or determining whether a sum, a difference, a product or a quotient between, or by, two end pressures being selected from the first, the second and the third end pressure, two pressure differences being selected from the first, the second and the third pressure difference, or two compliances being selected from the first, the second and the third compliance, falls below or exceeds a predetermined value.

33. The method according to claim 29, wherein actuating at least one conveying device of the group of conveying devices takes place at a first operating point with related to that conveying device, and wherein actuating at least one other conveying device from the group of conveying devices takes place at a second operating point related to that conveying device, wherein the first operating point and the second operating point differ from each other.

34. The method according to claim 29, with the additional step: emitting an acoustic and/or optical alarm in case the evaluation reveals unacceptable results, wherein unacceptable results include leaving predetermined thresholds, falling below the lower limit or exceeding the upper limit, leaving an acceptable value range, and/or exceeding a predetermined value.

35. The method according to claim 29, with the additional step: automatically providing a correction factor for the target conveying activity for at least one of the conveying devices of the group of conveying devices.

36. The method according to claim 29, wherein actuating a conveying device comprises: specifying the target conveying activity for, or at, at least one of the conveying devices by specifying at least a number of steps and/or a step angle, and/or specifying the target conveying activity for at least one of the conveying devices by specifying at least a number of pump strokes, and/or specifying the target conveying activity for at least one of the conveying devices by specifying a conveying duration.

37. The method according to claim 29, wherein the receptacle comprises or consists of at least a first and/or a second concentrate supply container and/or sections of the waste water branch of a balancing system.

38. The method according to claim 29, wherein the receptacle comprises a section within a liquid line of a dialysis liquid system.

39. The method according to claim 29, wherein at least one conveying device of the group of conveying devices is embodied as an ultrafiltration pump, at least one as a bicarbonate pump and/or at least one as a natrium pump.

40. The method according to claim 29, wherein at least one conveying device of the group of conveying devices is a positive displacement pump, wherein the displacement pump is one of: a membrane pump, eccentric membrane pump, hose pump, roller pump, gear pump or piston pump.

41. A control device or a closed-loop control device, configured in order to prompt or execute the method according to claim 29 in interaction with a blood treatment apparatus.

42. A blood treatment apparatus comprising: a dialysis liquid system comprising a receptacle for containing liquid; a pressure measuring device for measuring a pressure prevailing in the receptacle; a evaluation unit configured for evaluating end pressures, pressure differences and/or compliances; a group of conveying devices which consists of: a first conveying device, a second conveying device and a third conveying device, wherein each of the conveying devices of the group of conveying devices is in fluid communication with the receptacle; and a control device or a closed-loop control device according to claim 41 and configured for prompting execution of a method for checking conveying activity of the first conveying device, of the second conveying device and of the third conveying device, the method comprising: setting a predetermined initial pressure in the receptacle while the receptacle is closed and completely liquid-filled, or measuring a pressure prevailing therein by a first pressure measurement and defining the measured pressure as an initial pressure; actuating one conveying device of the group of conveying devices such that it accomplishes a target conveying activity required with respect to the one conveying device in order to convey a predetermined liquid volume out of the receptacle; and measuring, in a second pressure measurement, the pressure prevailing in the receptacle after the conveying activity of the one conveying device has been completed, wherein the measured pressure is an end pressure, wherein the setting, the actuating, and the measuring is carried out successively for each conveying device of the group of conveying devices, whereby for conveying by the first conveying device there are determined a first end pressure and a first pressure difference between the initial pressure and the first end pressure, and/or a first compliance, whereby for conveying by the second conveying device there is determined a second end pressure and a second pressure difference between the initial pressure and the second end pressure, and/or a second compliance, and whereby for conveying by the third conveying device there is determined a third end pressure and a third pressure difference between the initial pressure and the third end pressure, and/or a third compliance, the method further comprising evaluating: (i) at least the first end pressure, the second end pressure and the third end pressure, or (ii) at least the first pressure difference, the second pressure difference and the third pressure difference, or (iii) at least the first compliance, the seconds compliance and the third compliance, with regard to deviation of an actual conveying activity of the first, second and/or third conveying device from the respectively requested target conveying activity.

43. The blood treatment apparatus according to claim 42, wherein the evaluation unit is configured such that the evaluation is carried out while obtaining a measure for the deviation of an actual conveying activity of the first, second and/or third conveying device from the controlled target conveying activity.

44. The blood treatment apparatus according to claim 42, wherein the evaluation unit is configured such that the evaluation is carried out by comparing the first pressure until the third end pressure, or the first until the third pressure difference, or the first until the third compliance with each other.

45. The blood treatment apparatus according to claim 42, wherein the evaluation further comprises: determining whether the first end pressure, the second end pressure, and the third end pressure, and/or whether the first pressure difference, the second pressure difference, and the third pressure difference, and/or whether the first compliance, the second compliance, and the third compliance, are within a limit, exceed or fall below a threshold, exceed a minimum value, and/or do not exceed a maximum value, and/or determining whether a sum, a difference, a product or a quotient between, or by, two end pressures being selected from the first, the second and the third end pressure, two pressure differences being selected from the first, the second, and the third pressure difference, or two compliances being selected from the first, the second, and the third compliance, falls below or exceeds a predetermined value.

46. The blood treatment apparatus according to claim 42, wherein actuating at least one conveying device of the group of conveying devices takes place at a first operating point with related to that conveying device, and wherein actuating at least one other conveying device from the group of conveying devices takes place at a second operating point related to that conveying device, wherein the first operating point and the second operating point differ from each other.

47. The blood treatment apparatus according to claim 42, further configured for outputting an acoustic and/or optical alarm in case the evaluation reveals unacceptable results, wherein unacceptable results include leaving predetermined thresholds, falling below the lower limit or exceeding the upper limit, leaving an acceptable value range, or exceeding a predetermined value.

48. The blood treatment apparatus according to claim 42, further configured for automatically providing a correction factor for the target conveying activity for at least one of the conveying devices from the group of conveying devices.

49. The blood treatment apparatus according to claim 42, wherein actuating a conveying device comprises: specifying the target conveying activity for, or at, at least one of the conveying devices by specifying at least a number of steps and/or a step angle, and/or, predetermining the target conveying activity for at least one of the conveying devices by specifying at least a number of strokes, and/or, predetermining the target conveying activity for at least one of the conveying devices by specifying a conveying duration.

50. The blood treatment apparatus according to claim 42, wherein the receptacle comprises or consists of at least a first and/or a second concentrate supply container and/or sections of the old water branch of a balancing system.

51. The blood treatment apparatus according to claim 42, wherein the receptacle is or encompasses a section in a liquid line of a dialysis liquid system.

52. The blood treatment apparatus according to claim 42, wherein at least one conveying device of the group of conveying devices is embodied as an ultrafiltration pump, at least one as a bicarbonate pump and/or at least one as a natrium pump.

53. The blood treatment apparatus according to claim 42, wherein at least one conveying device of the group of conveying devices is positive displacement pump, wherein the displacement pump is a membrane pump, eccentric membrane pump, hose pump, roller pump, gear pump or a piston pump.

54. A digital storage medium with electronically readable control signals, configured for configuring a control and/or closed-loop control device to a control and/or closed-loop control device by which the method may be prompted according to claim 29.

55. A computer product with a program code saved on a machine-readable carrier for configuring a control and/or closed-loop control device to a control and/or closed-loop control device by which the method may be prompted according to any claim 29.

56. A computer program with a program code for configuring a control and/or closed-loop control device to a control and/or closed-loop control device by which the method may be prompted according to claim 29.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0133] The following shall be described with reference to preferred embodiments thereof based on the accompanying drawings. The method and the blood treatment apparatus are described using the example of a hemodialysis apparatus. The method may also be used in the same way with other blood treatment apparatuses, for example with a hemodiafiltration apparatus.

[0134] The following applies in the figures:

[0135] FIG. 1 shows parts of a flow diagram of a dialysis liquid system of a blood treatment apparatus;

[0136] FIG. 1a shows a section of FIG. 1, which section is limited to the receptacle shown in FIG. 1;

[0137] FIG. 1b shows the parts of the flow diagram of FIG. 1 with a clarifying illustration of a filling;

[0138] FIG. 2 shows an exemplary course of the method in a pressure-time diagram;

[0139] FIG. 3a shows an exemplary course of the method of a further embodiment in which the pressure differences are considered; and

[0140] FIG. 3b shows an exemplary course of the method of a further embodiment in which calculated compliances are considered for evaluation.

DETAILED DESCRIPTION

[0141] FIG. 1 shows parts of a flow diagram of a dialysis liquid system 1 (also referred to as hydraulics) of a blood treatment apparatus 100.

[0142] In the dialysis liquid system 1, a plurality of pumps, valves, actuator, sensors and other components are present. All of them may be independently connected to the control device or closed-loop control device 29 in signal communication and may optionally be controlled or read by the latter.

[0143] The aforementioned pumps include, amongst others, the bicarbonate pump, which is here exemplarily considered as the first conveying device F1. Further, F2 denotes the natrium pump, which is here considered as the second conveying device, and F3 denotes the ultrafiltration pump which represents the third conveying device.

[0144] The conveying devices F1, F2, F3 are present in the dialysis liquid system 1 connected in fluid communication with each other. They are fluidically connected to each other via the lines extracted and shown in bold in FIG. 1a. The lines which connect said conveying devices are fluidically cut off or disconnected from an exterior on one hand by the conveying devices F1, F2, F3 and on the other hand by valves V03, V05, V07, V09, V11, V25. The volume limited by the aforementioned conveying devices F1, F2, F3 and valves V03, V05, V07, V09, V11, V25 results therefore in a sealed vessel or a composite of sealed but communicating lines or vessels and is referred to herein as receptacle. Other terms, such as volume, liquid receiving section, etc. would also be conceivable by the present disclosure instead of “receptacle”.

[0145] The receptacle in FIG. 1a shown by omitting or not illustrating those elements of FIG. 1 not involved in establishing its sealed volume, is referred to herein as receptacle 71, see FIG. 1a.

[0146] The three conveying devices F1, F2, F3 are arranged with respect to the receptacle 71 such that they can convey the liquid present in the receptacle 71 out of the latter, which they sequentially do when the method is in process.

[0147] The pressure gauge present in the receptacle with or by which, e.g., the first and the second pressure measuring may be carried out, is designated in FIG. 1 with S07. Like any other pressure sensor used, this pressure gauge may have the highest measuring accuracy of all pressure gauges present in the receptacle. Other pressure gauges than the pressure sensor S07 described here are alternatively also possible. The pressure gauge used may be an analog-to-digital converter (ADC).

[0148] FIG. 1a shows the receptacle already shown in FIG. 1. The components not involved in establishing the sealed receptacle 71 which are not shown in FIG. 1 are not shown again in FIG. 1a for better clarity.

[0149] FIG. 1b shows the parts of the flow diagram of FIG. 1. The FIG. 1b clarifies or illustrates by the drawn arrows a first filling of the receptacle 71 such that it preferably contains only liquid, but not also gas. This may be done by a liquid source 73 which is likewise in fluid communication with the receptacle 71. The same applies for a refilling, after the first or the second conveying device F1, F2 has each conveyed a conveying volume out of the receptacle 71 when executing the method according to the present disclosure.

[0150] In some embodiments, the filling may be done optionally also from an external source, for example a liquid bag.

[0151] Through the filling, an initial pressure is defined within the receptacle 71. This initial pressure may be adjusted or set by the use of the liquid source 73, alternatively or additionally, for example also via the valve V11, e.g., when the filling is done via a pump in an undefined manner. In FIG. 1b, the filling takes place by opening the valve V09. The same applies to a refilling as described supra. Thereby, the other valves limiting the receptacle 71 are optionally closed.

[0152] Optionally, each valve connected to the receptacle 71 may therefore be opened for the filling and closed again, in which case the other valves of the receptacle 71 are preferably closed.

[0153] FIG. 2 shows an exemplary course of the method according to the present disclosure in a diagram of pressure [P] over time [t].

[0154] The method starts at t0, after the initial pressure P_0 has been set in the receptacle 71, which may take place by the liquid source 73 and may possibly be checked or monitored by the pressure gauge S07.

[0155] At the time point t1, the first conveying device F1 conveys liquid out of the receptacle according to the controlled conveying activity of this conveying device, upon which or for which reason the pressure gauge S07 or another pressure sensor detects or determines a drop of the pressure prevailing in the receptacle 71 to P_1, the first end pressure, after the first conveying device has completed the discharge of liquid.

[0156] After discharging liquid by the first conveying device F1 and after the pressure P_1 resulting in the receptacle 71 thereupon has been determined, the pressure is again set to the initial pressure P_0.

[0157] At time point t2, the second conveying device F2 now conveys which is why a pressure P_2 which is reduced compared to the initial pressure P_0 is set in the receptacle 71 as a new, second end value.

[0158] After refilling the receptacle 71 such that the initial pressure P_0 prevails again, the third conveying device F3 conveys liquid out of said receptacle 71 which leads to a new, third end pressure P_3.

[0159] The evaluation of the three end pressures P_1, P_2 and P_3 shows that although the P_1 and P_2 are indeed quite close to each other, but not the third end pressure P_3.

[0160] Since the receptacle 71 exhibited constant or unchanged compliance during the checking of the three conveying devices F1, F2 and F3 and comprised a constant liquid volume (here exemplarily at an always identical initial pressure P_0), the second conveying device F2 has conveyed slightly less liquid out of the receptacle 71 than the first conveying device F1, but significantly more than the third conveying device F3.

[0161] The evaluation of the three end pressures P_1, P_2 and P_3 may be (or encompass) the answer to the question whether the three end pressures are within a threshold window 91 or not. If they are all within the predetermined threshold window 91, then it may for this case be for example determined that the conveying accuracy of none of the three conveying devices F1, F2 and F3 deviates from the permissible measure. However, if the spread between any two end pressure values would be greater than the extent of the threshold window 91 so that not all three end pressures could be encompassed therein, then one would assume an inadmissible deviation of at least one of the three conveying devices. Possibly, the third conveying device F3 has conveyed more than it should have. An alarm could be provided for this case. Such an alarm could already encompass the notification as to which of the conveying devices F1, F2 and F3 deviates, with regard to its accuracy, from the other two conveying devices.

[0162] In this, it is of importance that it does not have to be determined a priority where the threshold window has to lie, i.e., which absolute pressure value determines its lower limit, and which absolute pressure value determines its upper limit. It is sufficient to determine how far the end pressure of one of the conveying devices may deviate from the end pressure of one of the other two conveying devices. Changes, which relate to the volume of the receptacle, the compliance of the receptacle, which may change, e.g., after replacement of a line in the course of maintenance or repair, etc. have no influence on the method according to the present disclosure. There is no need to communicate such changes to the system, which helps to keep the effort low, for example after a maintenance.

[0163] FIG. 3a shows the basis for the alternative evaluation based on the end pressures P_1, P_2 and P_3 assumed in FIG. 3. In this alternative evaluation, it is not the relative position of the three end pressures which is considered, rather the relative position of the three pressure differences ΔP 1, ΔP_2, ΔP_3 are compared to each other. Thus, the pressure differences are here compared to each other, each resulting as a difference between initial pressure P_0 and the respective end pressure. It can again be seen that a pressure difference, namely that achieved with the third conveying device, differs most.

[0164] FIG. 3b shows the basis for a further alternative evaluation based on the end pressures P_1, P_2 and P_3 assumed in FIG. 3. In this alternative evaluation, it is not the relative position of the three end pressures which is considered, rather the relative position of the three compliances C_1, C_2 and C_3 are compared to each other. Thus, the compliances calculated as explained supra are here compared to each other. Said relative position should be the same within acceptable tolerances. It can be seen again that a compliance C, namely the one calculated for the discharge using the third conveying device F3, differs most.

[0165] The evaluation for the embodiments shown in FIGS. 3a and 3b may be carried out as described herein.

LIST OF REFERENCE NUMERALS

[0166] 100 blood treatment apparatus [0167] 1 dialysis liquid system [0168] 29 control device or closed-loop control device [0169] 71 receptacle or receptacle [0170] 73 liquid source [0171] 91 threshold window [0172] F1 first conveying device, here exemplarily: bicarbonate pump [0173] F2 second conveying device, here exemplarily: natrium pump [0174] F3 third conveying device, here exemplarily: ultrafiltration pump [0175] S07 pressure gauge or sensor [0176] V03 valve [0177] V05 valve [0178] V07 valve [0179] V09 valve [0180] V11 valve [0181] V25 valve [0182] H21 first concentrate supply container [0183] H22 second concentrate supply container [0184] P_0 initial pressure [0185] P_1 first end pressure [0186] P_2 second end pressure [0187] P_3 third end pressure [0188] ΔP_1 first pressure difference [0189] ΔP_2 second pressure difference [0190] ΔP_3 third pressure difference [0191] C compliance [0192] C_1 first compliance [0193] C_2 second compliance [0194] C_3 third compliance [0195] t time