Feedback control of ultrafiltration to prevent hypotension

• US 7,175,809 B2
• Filed: 03/16/2004
• Issued: 02/13/2007
• Est. Priority Date: 12/29/2000
• Status: Expired due to Term

• Current Assignee: Gambro Lundia AB (Baxter International Inc.)
• Original Assignee: CHF Solutions, Inc.
• Inventors: Levin, Howard R., Gelfand, Mark, O'Mahony, John
• Primary Examiner(s): Zalukaeva; Tatyana
• Assistant Examiner(s): DEAK, LESLIE R
• Application Number:
  US10/801,059
• Publication Number:
  US 20040176813A1
• Time in Patent Office: 1,064 Days
• Field of Search: 210/654, 210/646, 210/739, 210/741, 210/85, 210/195.2, 210/327.1, 210/416.1, 210/433.1, 210/500.21, 210/645, 210/321.71, 210/90, 210/97, 604/4.01, 604/5.01, 604/5.04, 604/6.09, 604/6.11, 604 65- 67, 422 44- 48
• US Class Current: 422/44
• CPC Class Codes: A61M 1/34 Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
• CPC Class Codes: A61M 1/341 by measuring the filtrate rate or volume
• CPC Class Codes: A61M 1/36 Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
• CPC Class Codes: A61M 2205/3303 Using a biosensor
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3375 Acoustical, e.g. ultrasonic, measuring means
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)

Abstract

A method and system for the extracorporeal treatment of blood to remove fluid from the fluid overloaded patient is disclosed that non-invasively measures an oxygen level in the venous blood. The oxygen blood level is used to detect when hypotension is about to occur in a patient. The oxygen level measurements are used as feedback signals. These feedback signals are applied to automatically control the rate of fluid extraction to achieve the desired clinical outcome and avoid precipitating a hypotensive crisis in the patient.

Claims

1. A system for treating blood from a patient comprising:

an extracorporeal circuit having a blood passage including a blood withdrawal tube, a filter and an infusion tube, said filter having filter blood passage in fluid communication with the withdrawal tube, a blood outlet in fluid communication with the infusion tube, a filter membrane in fluid communication with the blood passage, a filter output section on a side of the membrane opposite to the blood passage, and a filtrate output line in fluid communication with the filter output section;

a biosensor coupled to said extracorporeal circuit and generating a feedback signal indicative of cardiac output of the patient;

a filtrate pump coupled to the filtrate output line and adapted to draw filtrate fluid from the filter at a controlled filtration rate, and

a filtrate pump controller regulating the controlled filtration rate based on the feedback signal, wherein the pump controller includes a processor and a memory storing a control algorithm to determine whether a feedback signal threshold is beyond the feedback signal and storing a baseline feedback signal generated by the biosensor during an initial phase of blood filtration treatment, said controller programmed to execute the control algorithm to reduce the controlled filtration if the feedback signal exceeds the feedback signal threshold, wherein the signal threshold is automatically determined by the controller and is a function of the baseline feedback signal.

2. A system as in claim 1 wherein the feedback signal is indicative of an oxygen level in the venous blood.

3. A system as in claim 1 wherein the feedback signal

threshold is determined based on a sum of a feedback signal obtained during an initial phase of a treatment of the patient and a predetermined current feedback signal change.

4. A system as in claim 1 wherein the filter is a hemofilter.

5. A system as in claim 1 wherein the treatment device is a dialysis filter.

6. A system as in claim 1 wherein the treatment device is an ultrafiltration filter.

7. A system as in claim 1 wherein said control algorithm includes a control step of automatically increasing the reduced filtrate flow, if the feedback signal is within the threshold.