RESTLESS BUTTON ACCESS HEMORRHAGE/NEEDLE DISCONNECTION

Abstract

A monitoring device of a dialysis machine and a method for detecting a venous needle disconnection via venous pressure monitoring based on a threshold value setting. The device includes a button, preferably arranged on a screen of the dialysis machine. The button is configured, upon actuation, to set a lower threshold value and an upper threshold value depending on an actual pressure and to detect an incremental decrease in the venous pressure.

Claims

1. A monitoring device of an extracorporeal blood treatment machine for detecting a venous needle disconnection via venous pressure monitoring based on a threshold value setting, the monitoring device comprising a button that is configured, upon actuation, to cause the monitoring device to set a lower threshold value and an upper threshold value depending on an actual pressure and to detect an incremental decrease in the venous pressure, wherein an incremental decrease is present when the new lower threshold value falls more than a predetermined percentage from the previous floating average value such that the lower threshold value is smaller than the addition of the new lower threshold value and the predetermined percentage.

2. The monitoring device according to claim 1, wherein the actual pressure is a floating average value in a range of 48 mmHg to 69 mmHg.

3. The monitoring device according to claim 2, wherein the lower threshold value and the upper threshold value are asymmetrical to the actual pressure and/or a difference between the upper threshold value and the actual pressure is greater than a difference between the lower threshold value and the actual pressure.

4. The monitoring device according to claim 1, wherein the lower threshold value is settable 25 mmHg below the actual pressure and the upper threshold value is settable 40 mmHg above the actual pressure.

5. The monitoring device according to claim 2, wherein the monitoring device is provided and configured to increase the lower threshold value to a new lower threshold value after a predetermined time has elapsed, if the floating average value has increased by more than a predetermined amount, or to decrease the lower threshold value to a new lower threshold value if a distance between the new floating average value and the lower threshold value is less than a lower target threshold value.

6. The monitoring device according to claim 5, characterized in that the monitoring device is provided and configured to save the new lower threshold value and to check whether an incremental decrease is present, wherein in case of an incremental decrease the monitoring device is provided to output an alarm.

7. The monitoring device according to claim 6, wherein the monitoring device is provided and configured to output an alarm when a lower threshold value is undershot and when an upper threshold value is exceeded, wherein at least the alarm when the value falls below the lower threshold value is to be acknowledged via a PIN entry.

8. The monitoring device according to claim 7, wherein the monitoring device is provided and configured to issue an alarm different from the first alarm for a predetermined number of alarms to be acknowledged with a PIN input.

9. An extracorporeal blood treatment machine, which is characterized by a monitoring device according to one of the preceding claims.

10. A monitoring method for detecting a venous needle disconnection with venous pressure monitoring based on a threshold value setting, comprising the following steps: actuating the button to set a lower venous threshold value and an upper venous threshold value based on an actual pressure, detecting a drop below the lower venous threshold value, decreasing or increasing the lower threshold value to a new lower threshold value, saving the new lower threshold value, and checking if an incremental decrease is present wherein an incremental decrease is present if the new lower threshold value falls more than a predetermined percentage from the previous floating average value such that the lower threshold value is smaller than the addition of the new lower threshold value and the predetermined percentage.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG. 1 is a representation illustrating an evaluation to determine a floating average value of venous pressure.

[0046] FIG. 2 is a representation illustrating an incremental decrease according to the prior art.

[0047] FIG. 3 is a representation illustrating an incremental decrease according to the present disclosure.

[0048] FIG. 4 is a flowchart illustrating the method steps according to the monitoring method according to the present disclosure.

[0049] FIGS. 5 to 7 are each a representation illustrating a display of a dialysis machine.

[0050] FIG. 8 shows an exemplary dialysis machine with a display integrated therein according to FIGS. 5 to 7.

DETAILED DESCRIPTION

[0051] The following describes configuration examples of the present disclosure based on the accompanying figures.

[0052] FIG. 1 is a representation illustrating an evaluation to determine a floating average value of the venous pressure. FIG. 1 is a diagram showing the number of treatments with a factor of 10.sup.4 on the x-axis and the venous pressure in mmHg on the y-axis. In the diagram, empty points are drawn for the venous pressure of the upper threshold value and full points for the venous pressure (hereinafter also referred to as PV) of the lower threshold value. Via these points, it is possible to determine a floating average value x for the upper threshold value and a floating average value x for the lower threshold value.

[0053] Based on the diagram, an evaluation of about 20,000 hemodialysis treatments was conducted and the starting values of about 69 mmHg were determined as floating average value x for the upper threshold value and about 48 mmHg as floating average value x for the lower threshold value. These average pressure values are significantly higher than the pressure values used in the present disclosure for setting the asymmetric venous pressure window of 40 mmHg and 25 mmHg. This leads to an increase in the sensitivity of the monitoring.

[0054] FIG. 2 is a representation illustrating an incremental decrease according to the prior art. The graph of FIG. 2 as well as the graph of FIG. 3 has the time in seconds in a time range from 6000 seconds to 7800 seconds on the x-axis and the venous pressure in mmHg on the y-axis.

[0055] In the graph of FIG. 2, a venous pressure course according to the prior art is shown, which is represented with a continuous line under the designation ‘venous pressure_current’. A first upper threshold value (hereinafter also referred to as ‘venous_max_current’) is drawn at 250 mmHg and a first lower threshold value (hereinafter also referred to as ‘venous_min_current’) is drawn at 200 mmHg. After about 300 seconds, an alarm is triggered due to the dropped current venous pressure, which causes the access to be checked and the threshold values to be set to the current new pressure value. After another 300 seconds, the lower threshold value is corrected again, in this case increased and the upper threshold value is decreased. At second 7200, the pressure values exceed the upper threshold value, resulting in only the upper threshold value being adjusted. After the pressure course triggers another alarm in the further course of time due to a drop in pressure, the threshold values are corrected downwards according to the current pressure.

[0056] An incremental, hidden decrease in pressure can be detected in the pressure course. This venous incremental decrease in pressure cannot be detected by previous algorithms because a lower threshold value is adjusted to the current pressure course after triggering a venous pressure alarm or readjusting the blood flow. This does not take into account the type of previous alarm or alarms.

[0057] In the graph of FIG. 3, which is very similar to the graph in FIG. 2, a venous pressure course (according to FIG. 2) is shown, which is represented with a continuous line under the designation ‘venous_pressure_current’. A first upper threshold value (hereinafter also referred to as ‘venous_max_current’) is drawn at 260 mmHg and a first lower threshold value (hereinafter also referred to as ‘venous_min_current’) is drawn at 200 mmHg. After approximately 300 seconds, an alarm is triggered due to the decreased current venous pressure, which causes the access to be checked and the threshold values to be set to the current new pressure value. After another 300 seconds, the lower threshold value is corrected again, in this case increased and the upper threshold value is decreased. At second 7200, the pressure values exceed the upper threshold value, whereby only the upper threshold value is adjusted. After the pressure course triggers another alarm in the further course of time shortly before second 7400 due to a drop in pressure, the threshold values are corrected downwards according to the current pressure. Between second 7600 and second 7700, the lower threshold value was adjusted again.

[0058] FIG. 3 therefore shows the upper and lower threshold values according to the pressure window as the starting value. Furthermore, FIG. 3 shows the threshold value adjustments provided according to the invention, wherein the procedure is described in more detail later for FIG. 4.

[0059] FIG. 4 is a flow chart for the representation of the method steps according to the monitoring method according to the present disclosure. In FIG. 4, in a first step S1, the restless button is pressed and based on a current venous pressure, according to step S2, a floating average value x is determined. After pressing the button according to S1, based on the floating average value x, an asymmetric venous pressure window with an upper and a lower threshold value LCL is automatically set.

[0060] In the OR logic R1, when an alarm is triggered, it is determined/checked whether a predetermined time of preferably 300 seconds has elapsed since the last setting of the asymmetric pressure window.

[0061] In the case where a predetermined time has elapsed since the last setting of the upper and lower threshold value LCL according to R1, i.e. the predetermined time Δt>300 seconds (R1: yes), the current venous pressure (ACTUAL pressure) is detected in the OR logic R2 and it is checked whether the floating average value x has increased by more than 2.5 mmHg. If the floating average value has increased by more than 2.5 mmHg (R1: yes, increased), the previous lower threshold value LCL is increased correspondingly according to step S3 and a new lower threshold value nLCL is provided as a target threshold value.

[0062] In the case where it is determined in R2 that a distance between the current averaged ACTUAL value and the previous lower threshold value is smaller than a target threshold value, the lower threshold value is reduced correspondingly according to step S4 and a new lower threshold value nLCL is provided as a target threshold value.

[0063] In the case where neither step S3 nor step S4 is fulfilled in R2, the blood pump is reset according to step S5 (R2: no) in accordance with the current ACTUAL pressure.

[0064] In the case where a predetermined time has not elapsed since the last setting of the upper and lower threshold value LCL according to R1, the lower and upper threshold value LCL according to step S6 (R1: no) are kept unchanged.

[0065] If a change of the lower threshold value is necessary following step S3 or step S4, the new lower threshold value nLCL is saved in step S7. In a subsequent OR logic R3, it has to be checked whether the most recently set lower threshold value LCL does not deviate by more than a predetermined percentage p % from the floating average value x of the last predetermined time, preferably the last 300 seconds. In the case where the previous lower threshold value LCL is less than the sum of the new lower threshold value nLCL and the predetermined percentage p % of the floating average value x (R3: yes), there is an incremental decrease in venous pressure according to step S8 and the device displays a venous needle disconnection alarm and the blood pump stops. The device restarts the monitoring method. In the case where R3 does not apply, the monitoring method follows step S9 (R3: no) and the new venous lower threshold value nLCL is set.

[0066] FIGS. 5 to 7 are each a representation illustrating a display 2 of a dialysis machine.

[0067] Here, FIG. 5 shows the start display on the display 2 with a button 1 (also called ‘restless button’). Button 1 is located in a field with the heading ‘restless patient’. This field also shows the pressure course of the venous pressure. In addition, all of the patient's vital signs are shown on display 2 with the start display.

[0068] FIG. 6 shows, after an alarm has been triggered due to a venous needle disconnection, a detailed description of how to resolve the alarm including the possible causes for the alarm that occurred. The following points are exemplary causes for an alarm due to falling below a lower threshold value:

[0069] (1) Decannulation of the venipuncture cannula

[0070] (2) Bleeding in the tissue

[0071] (3) Tube rupture in venous tubing system

[0072] (4) Loosening of tubing connections

[0073] (5) Blood clot formation in the dialyzer

[0074] Solutions suggested for this are shown as examples on the display as follows:

[0075] (1) Decannulation of the venipuncture cannula: check the venous puncture site, whether the needle is still in the shunt and whether blood is present outside the blood circuit.

[0076] (2) Bleeding in the tissue: check for penetration into the tissue around the puncture site (look for bruising).

[0077] (3) Tube rupture in the venous tubing system: check the entire venous blood tubing system from the venous bubble trap to the puncture site for ruptures.

[0078] (4) Detaching tubing connections: check the tubing connection from the tubing system to the cannula and also the venous pressure transducer.

[0079] (5) Blood clot formation in the dialyzer: check the dialyzer for blood clots and flush it with saline solution if necessary.

[0080] In addition, a button for unlocking the alarm is located below the detailed description.

[0081] FIG. 7 shows, after an alarm has been triggered due to a venous pressure increase, a detailed description of how to resolve the alarm including the possible causes for the alarm that occurred. The following items are examples of causes for an alarm due to an upper threshold value being exceeded:

[0082] (1) Vein tube twisted or kinked

[0083] (2) Filter screen of the bubble trap blocked

[0084] (3) Blood clot in the area of the fistula

[0085] Proposed solutions for this are shown on the display as examples as follows:

[0086] (1) Check the tubing system for venous blood for twists or kinks.

[0087] (2) Check filter screen in venous bubble trap for blockage. Possibly change the venous blood tubing system.

[0088] (3) Possible venous shunt stenosis. Consult a vascular surgeon if necessary.

[0089] In addition, a button for unlocking the alarm is located below the detailed description.

[0090] FIG. 8 shows an exemplary dialysis machine 3 with an integrated display 2 according to FIGS. 5 to 7.