METHOD FOR MEASURING CENTRAL VENOUS PRESSURE OR RESPIRATORY EFFORT

• US 20080081961A1
• Filed: 06/14/2007
• Published: 04/03/2008
• Est. Priority Date: 06/14/2006
• Status: Active Grant

• Current Assignee: Watermark Medical, Inc. (BioSerenity SAS)
• Original Assignee: Advanced Brain Monitoring
• Inventors: Westbrook, Philip, Popovic, Djordje, Berka, Chris, Zavora, Timothy, Levendowski, Daniel, Cvetinovic, Milenko
• Granted Patent: US 7,691,067 B2
• Time in Patent Office: Days
• US Class Current: 600/301
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/037 Measuring oesophageal pressure
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/1073 Measuring volume, e.g. of limbs
• CPC Class Codes: A61B 5/1135 by monitoring thoracic expansion
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61B 5/4818 Sleep apnoea

Abstract

Photoplethysmography (PPG) is obtained using one red (e.g., 660 nm) and one infrared (e.g., 880 to 940 nm) light emitting diode with a single photo diode in combination with a pressure transducer thereby allowing both CVP and SpO2 to be measured simultaneously. The system also includes sensors capable of measuring position, angle and/or movement of the sensor or patient. Once the PPG signal is acquired, high pass adaptive and/or notch filtering can be used with one element of the filter from the red and infrared signals used to measure the arterial changes needed to compute SpO2 and the other element of the signal can be used to measure CVP changes.

Claims

1. A non-invasive method for measuring central venous pressure changes comprising:

monitoring photoplethysmography with a detector including a pressure sensor;

monitoring the position of the patient;

filtering the photoplethysmography signal using information form the pressure sensor and the position of the patient to measure the arterial changes needed to compute SpO2 and central venous pressure changes.

2. A non-invasive system for measuring central venous pressure comprising:

an optical sensor, a pressure sensor and a position sensor;

an acquisition Signal processing Quantification module in communication with the sensors and configured to extract central venous pressure information from the received signals of the sensors and transform it as required to extract the discrete central venous pressure information.

3. The systems and methods substantially as described above.