METHOD FOR USING PHOTOPLETHYSMOGRAPHY TO OPTIMIZE FLUID REMOVAL DURING RENAL REPLACEMENT THERAPY BY HEMODIALYSIS OR HEMOFILTRATION

• US 20110098545A1
• Filed: 01/06/2011
• Published: 04/28/2011
• Est. Priority Date: 09/15/2006
• Status: Active Grant

• Current Assignee: Edward Allan Ross, Richard J. Melker
• Original Assignee: Edward Allan Ross, Richard J. Melker
• Inventors: Melker, Richard J., Ross, Edward Allan
• Granted Patent: US 9,155,826 B2
• Time in Patent Office: Days
• US Class Current: 600/324
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/6819 Nose
• 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 1/3403 Regulation parameters
• CPC Class Codes: A61M 1/341 by measuring the filtrate rate or volume
• CPC Class Codes: A61M 1/3609 Physical characteristics of the blood, e.g. haematocrit, urea
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/50 with microprocessors or computers

Abstract

Disclosed herein are methods, systems and devices to monitor vascular volume status during renal replacement therapy utilizing at least one oximetry/photoplethysmography sensor. The methods, systems and devices provide an alternative to conventional vascular volume monitoring methods during renal replacement therapy while enabling reliable, non-invasive, and automatic monitoring of vascular volume to avert patient hypotension. The methods, systems and devices may be employed in the context of both inpatient and outpatient dialysis facilities and may also be incorporated into conventional hemodialysis and hemofiltration techniques and equipment.

Claims

1. A system for optimizing fluid removal during renal replacement therapy comprising:

at least one pulse oximeter/photoplethysmography probe configured for securing to a central source site of a patient and effective to generate a photoplethysmography signal stream; and

a computer communicatingly connected to said at least one pulse oximeter/photoplethysmography probe, said computer comprising at least one processing module, a first computer-readable program code module for causing said computer to process signals of said at least one pulse oximeter/photoplethysmography probe to obtain a pulsatile cardiac component signal or a venous capacitance component signal, or both;

a second computer-readable program code module for causing said computer to analyze said pulsatile cardiac component signal or venous capacitance component signal, or both to determine a change in blood flow and/or volume status; and

a third computer-readable program code module for causing an adjustment in said therapy in response to a change in said pulsatile cardiac component signal and/or said venous capacitance component signal so as to stabilize said pulsatile cardiac component signal and/or said venous capacitance component signal to a target level without the need for user input.

2. The system of claim 1, wherein said computer further comprises a display screen.

3. A computer program product for use with a computer for controlling renal replacement therapy comprising at least one processing module, said product comprising:

a computer-usable medium comprising computer readable program code modules embodied in said computer-usable medium;

computer readable first program code module for causing said computer to process plethysmography signals obtained from a pulse oximeter/photoplethysmography probe by separating out a pulsatile cardiac component signal stream and a venous capacitance component signal stream;

computer-readable second program code module for causing said computer to analyze said pulsatile cardiac component signal stream or said venous capacitance signal stream, or both, to determine a change in blood flow and/or volume status; and

a third computer-readable program code module for causing an adjustment in said therapy in response to a change in said pulsatile cardiac component signal and/or said venous capacitance component signal so as to stabilize said pulsatile cardiac component signal and/or said venous capacitance component signal to a target level without the need for user input.

4. A device useful for determining a change in blood flow and/or volume status, said device comprising a computer configured to communicate with at least one pulse oximeter/photoplethysmography probe and for controlling renal replacement therapy,

said computer comprising at least one processing module;

a first computer-readable program code module for causing said computer to process signals of said at least one pulse oximeter/photoplethysmography probe to obtain an pulsatile cardiac component signal or a venous capacitance component signal, or both, and a second computer-readable program code module for causing said computer to analyze said pulsatile cardiac component signal or venous capacitance component signal, or both, to determine when a change to said blood flow and/or volume status occurs, and a third computer-readable program code module for causing an adjustment in said therapy in response to a change in said pulsatile cardiac component signal and/or said venous capacitance component signal so as to stabilize said pulsatile cardiac component signal and/or said venous capacitance component signal to a target level without the need for user input.

5. The device of claim 4, further comprising a display screen effective to display information to a user of said device.

6. A system for optimizing fluid removal for a patient undergoing renal replacement therapy comprising:

at least one pulse oximeter/photoplethysmography probe configured for securing to a central source site of said patient and effective to generate a photoplethysmography signal stream; and

a computer communicatingly connected to said at least one pulse oximeter/photoplethysmography probe, said computer comprising at least one processing module, and at least two computer-readable program code modules;

a first computer-readable program code module for causing said computer to process signals of said at least one pulse oximeter/photoplethysmography probe to obtain a pulsatile cardiac component signal or a venous capacitance component signal, or both; and

a second computer-readable program code module for causing said computer to adjust the ultrafiltration rate during said renal replacement therapy in response to said pulsatile cardiac component signal and/or said venous capacitance component signal so as obtain target pulsatile cardiac component signal and/or target venous capacitance component signal levels.

7. A method of evaluating the strength of a patient'"'"'s compensatory mechanism, said method comprising perturbing a patient'"'"'s vascular system and monitoring the amplitude of a pulsatile cardiac component and venous capacitance component of a photoplethysmography signal stream from a central source site of said patient upon said perturbing step.

8. The method of claim 7, wherein less than a predetermined change in amplitude is indicative of a compromised compensatory mechanism.

9. The method of claim 7, wherein said perturbing comprises an intentional or incidental loss of fluid and/or blood.

10. The method of claim 7, wherein said perturbing occurs during a surgical procedure on said patient.

11. The method of claim 7, wherein said perturbing occurs by an extracorporeal therapy.

12. The method of claim 7, wherein said perturbing occurs by hemodialysis.

13. The method of claim 7, wherein said perturbing occurs by a noninvasive maneuver.