Method and device for extracorporeal blood treatment with a means for continuous monitoring of the extracorporeal blood treatment

• US 6,736,789 B1
• Filed: 10/21/1998
• Issued: 05/18/2004
• Est. Priority Date: 10/21/1997
• Status: Expired due to Term

• Current Assignee: Fresenius AG (Fresenius SE & Co. KGaA)
• Original Assignee: Fresenius Medical Care Deutschland GmbH (Fresenius Medical Care AG)
• Inventors: Spickermann, Reiner
• Primary Examiner(s): Bianco, Patricia
• Application Number:
  US09/176,744
• Time in Patent Office: 2,036 Days
• Field of Search: 604/4-6, 604/66, 604/29-31, 604/65, 604/47, 604/27, 604/4.01, 604/5.01, 422/44-48, 128/DIG.3
• US Class Current: 604/5.01
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61M 1/3413 Diafiltration
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/30 Blood pressure A61M2230/04 takes precedence
• CPC Class Codes: Y10S 128/03 Heart-lung

Abstract

A method and a device for continuous, noninvasive monitoring of an extracorporeal blood treatment, a patient'"'"'s blood pressure or a quantity that correlates with the blood pressure is measured and compared with a predetermined limit value. If the measured blood pressure or its relative change drops below the predetermined limit value, an activation or deactivation signal is generated to initiate an intervention in the treatment sequence. The blood treatment machine therefore has a control unit. The continuous, noninvasive measurement of blood pressure is based on a determination of the propagation rate or transit time of the pulse waves produced by the patient'"'"'s cardiac contractions and their propagation through the arterial system. To determine the pulse wave velocity or transit time, the blood treatment machine has an electrocardiograph and a device for detecting the pulse waves at a location on the patient remote from the heart.

Claims

1. A blood treatment device for extracorporeal blood treatment comprising:

a) an extracorporeal blood path connecting a subject to the blood treatment device, the blood treatment device having an inlet and an outlet, the extracorporeal blood path carrying blood from the subject to the blood treatment device inlet and from the blood treatment device outlet back to the subject;

b) a measurement device connected to the subject for continuously measuring a value selected from the group consisting of a pulse wave velocity and a pulse wave transit time;

c) a correlation device connected to the measurement device, the correlation device adapted to determine a correlative value correlating a blood pressure value to the measured value;

d) a comparison device connected to the correlation device, the comparison device adapted to compare the correlative value with a predetermined limit and generate a signal when the correlative value is outside the limit; and

e) a control unit connected to the comparison device, the control unit adapted to selectively initiate, based on a user preference, one of a plurality of changes in the subject'"'"'s extracorporeal blood treatment in response to the signal.

2. The device of claim 1, wherein the measurement device further comprises:

i) an electrocardiography device connected to the subject for recording the subject'"'"'s electrocardiogram;

ii) a pulse detection device connected to the subject for detecting the subject'"'"'s pulses;

iii) a time comparison device connected to the electrocardiography device and the pulse detection device, wherein the time comparison device is adapted to calculate the pulse wave transit time using the time between an R wave from the subject'"'"'s electrocardiogram (t₀) and time (t₁) of the pulse corresponding to the R wave.

3. The device of claim 2, wherein the subject'"'"'s pulse is measured by a device selected from the group consisting of a photoplethysmograph and a pressure sensor in the extracorporeal blood path.

4. The device of claim 3, wherein the subject'"'"'s pulse is measured by a pressure sensor located upstream of the blood treatment device.

5. The device of claim 2, wherein the correlation device is configured to calculate the blood pressure value from the pulse wave transit time using the equation:

6. The device of claim 1, wherein the blood treatment device is selected from the group consisting of a hemofiltration device, a hemodialysis device, and a cell separator device.

7. The device of claim 1, wherein the correlation device is adapted to determine a blood pressure correlation value that correlates with the blood pressure and correlate the blood pressure correlation value with the blood pressure value.

8. The device of claim 1, further comprising a NaCl delivery device connected to the control unit, the NaCl delivery device adapted for delivering NaCl solution to the extracorporeal blood path in response to the signal.

9. The device of claim 1, wherein the blood treatment machine further comprises an alarm generator connected to the control unit and adapted to generate an alarm when the blood pressure value is outside the blood pressure limit.

10. The device of claim 9, wherein the alarm generator is selected from the group consisting of an acoustical alarm and an optical alarm.

11. The device of claim 1, wherein the blood treatment device comprises a dialysis unit divided by a semipermeable membrane into a blood chamber and a dialysate chamber, the blood chamber having a blood inlet and a blood outlet, the blood chamber in fluid communication with the extracorporeal blood path, the dialysate chamber having a dialysate inlet and a dialysate outlet, the dialysate chamber connected to a dialysate path, the dialysate path further comprising a balancing device, an ultrafiltration device and an ultrafiltration pump connected to the control device, the ultrafiltration pump adapted to be activated and deactivated in response to the signal.

12. The device of claim 1, wherein the blood treatment machine further comprises a temperature stabilizing unit adapted to set the dialysate temperature to two or more different preset temperatures in response to the signal.

13. The device of claim 1, wherein the blood treatment machine further comprises a device for delivering electrolytes to the extracorporeal blood path in response to the signal.

14. The method of claim 13, wherein the device for delivering electrolytes delivers electrolytes selected from the group consisting of Na⁺ and K⁺.

15. The device of claim 1, wherein the blood treatment device further comprises a drug delivery device connected to the control unit and the subject and adapted for delivering blood pressure-stabilizing drugs to the subject in response to the signal.

16. The device of claim 1, wherein the correlation device is further adapted to generate a signal in response to a predetermined change in the blood pressure correlation value.

17. A hemodialysis machine comprising:

a) an extracorporeal blood path connecting a subject to a dialyzer having an inlet and an outlet, the extracorporeal blood path carrying blood from the subject to the inlet of the dialyzer and from the outlet of the dialyzer back to the subject;

b) a measurement device connected to the subject for continuously measuring a value selected from the group consisting of a pulse wave velocity and a pulse wave transit time, the measurement device further comprising a pulse detection device for detecting the subject'"'"'s pulses, the subject'"'"'s pulses being measured by a pressure sensor in the extracorporeal blood path;

c) a correlation device connected to the measurement device, the correlation device adapted to determine a correlative value correlating a blood pressure value to the measured value;

d) a comparison device connected to the correlation device, the comparison device adapted to compare the correlative value with a predetermined limit and generate a signal when the correlative value is outside the limit; and

e) a control unit connected to the comparison device, the control unit adapted to initiate a change in the subject'"'"'s extracorporeal blood treatment in response to the signal.

18. A hemofiltration machine comprising:

a) an extracorporeal blood path connecting a subject to a hemofilter having an inlet and an outlet, the extracorporeal blood path carrying blood from the subject to the inlet of the hemofilter and from the outlet of the hemofilter back to the subject;

b) a measurement device connected to the subject for continuously measuring a value selected from the group consisting of a pulse wave velocity and a pulse wave transit time, the measurement device further comprising a pulse detection device for detecting the subject'"'"'s pulses, the subject'"'"'s pulses being measured by a pressure sensor in the extracorporeal blood path;

c) a correlation device connected to the measurement device, the correlation device adapted to determine a correlative value correlating a blood pressure value to the measured value;

d) a comparison device connected to the correlation device, the comparison device adapted to compare the correlative value with a predetermined limit and generate a signal when the correlative value is outside the limit; and

e) a control unit connected to the comparison device, the control unit adapted to initiate a change in the subject'"'"'s extracorporeal blood treatment in response to the signal.