Method and system for acquiring biosignals in the presence of HF interference

• US 10,376,220 B1
• Filed: 08/10/2016
• Issued: 08/13/2019
• Est. Priority Date: 07/13/2007
• Status: Active Grant

• Current Assignee: NeuroWave Systems Inc.
• Original Assignee: NeuroWave Systems Inc.
• Inventors: Saliga, Thomas V, Bibian, Stephane, Zikov, Tatjana
• Primary Examiner(s): Berhanu, Etsub D
• Application Number:
  US15/233,200
• Time in Patent Office: 1,098 Days
• Field of Search: None
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 2018/00601 Cutting
• CPC Class Codes: A61B 2018/00839 Bioelectrical parameters, e.g. ECG, EEG
• CPC Class Codes: A61B 2018/1412 Blade
• CPC Class Codes: A61B 5/30 Input circuits therefor
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/389 Electromyography [EMG]
• CPC Class Codes: A61B 5/398 Electrooculography [EOG], e.g. detecting nystagmus; Electroretinography [ERG]
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: G01R 29/26 Measuring noise figure; Measuring signal-to-noise ratio

Abstract

The present invention, herein is a method and apparatus that significantly limits the effect of high frequency (“HF”) interferences on acquired electro-physiological signals, such as the EEG and EMG. Preferably, this method comprises of two separate electronic circuitries and steps or electronics for processing the signals. One circuit is used to block the transmission of HF interferences to the instrumentation amplifiers. It is comprised of a front-end active filter, a low frequency electromagnetic interference (“EMI”) shield, and an isolation barrier interface which isolates the patient from earth ground. The second circuit is used to measure the difference in potential between the two isolated sides of the isolation barrier. This so-called “cross-barrier” voltage is directly representative of the interference level that the instrumentation amplifier is subjected to. This circuit is used to confirm that the acquired signals are not corrupted by the interference.

Claims

1. A system for delivering anesthesia or sedation comprising an electrical system for acquiring signals from a subject in the presence of high frequency (HF) electrical interference comprising:

at least 2 electrodes adapted to be attached to a subject; and

physiological signal acquisition circuitry adapted to reject HF electrical interference, said circuitry comprising;

at least one front-end active input filter, and

an isolation barrier, and

a transmitter adapted to transmit data across the isolation barrier; and

an anesthesia or sedation drug delivery system adapted to deliver at least one anesthesia or sedation drug to the subject during surgery to reach and maintain a predetermined desired level of anesthesia or sedation using a closed-loop controller receiving output from a processor

wherein the physiological signal acquisition circuitry is further adapted to measure a level of remaining HF electrical interference across the isolation barrier and transmit measured physiological signals and the level of remaining HF electrical interference to the processor.

2. The system of claim 1, wherein the isolation barrier is a magnetic flux isolation barrier.

3. The system of claim 1, wherein said processor uses the measured level of remaining HF electrical interference to modify at least one behavior of the at least one active input filter.

4. The system of claim 1 wherein the circuitry further comprises a multistage amplification circuitry and an optimized low frequency shield.

5. The system of claim 1, wherein the measured level of remaining HF electrical interference is a quantitative measurement of the magnitude of HF electrical interference.

6. A system for acquiring signals from a subject in the presence of high frequency (HF) electrical interference comprising:

at least 2 electrodes adapted to be attached to a subject; and

physiological signal acquisition circuitry adapted to reject HF electrical interference, said circuitry comprising;

at least one front-end active input filter, and

an isolation barrier having both a patient side and a ground side, and

wherein the physiological signal acquisition circuitry is further adapted to measure a remaining level of HF electrical interference on the ground side of the isolation barrier and transmit measured physiological signals and the measured remaining level of HF electrical interference to a processor of the system, and the processor uses the measured level of remaining HF electrical interference to modify at least one behavior of the at least one active input filter.

7. The system of claim 6, wherein the isolation barrier is a magnetic flux isolation barrier.

8. The system of claim 6, further comprising an anesthesia or sedation drug delivery system adapted to deliver at least one anesthesia or sedation drug to the subject during surgery to reach and maintain a predetermined desired level of anesthesia or sedation using a closed-loop controller.

9. The system of claim 6 wherein the circuitry further comprises a multistage amplification circuitry and an optimized low frequency shield.

10. The system of claim 6, wherein the measured level of remaining HF electrical interference is a quantitative measurement of the magnitude of HF electrical interference.

11. A system for acquiring signals from a subject in the presence of high frequency (HF) electrical interference comprising:

at least 2 electrodes adapted to be attached to a subject;

physiological signal acquisition circuitry adapted to reject HF electrical interference and measure a level of remaining HF electrical interference, said circuitry comprising;

at least one front-end active input filter, and

an isolation barrier, and

a transmitter adapted to transmit data across the isolation barrier; and

a processor adapted to receive data from the physiological signal acquisition circuitry corresponding at least in part to measured physiological signals and at least in part to the measured level of remaining HF electrical interference and use the measured level of remaining HF electrical interference to modify at least one behavior of the at least one active input filter,

wherein the measured level of remaining HF electrical interference is a quantitative measurement of the magnitude of HF electrical interference.

12. The system of claim 11, wherein the isolation barrier is a magnetic flux isolation barrier.

13. The system of claim 11, further comprising an anesthesia or sedation drug delivery system adapted to deliver at least one anesthesia or sedation drug to the subject during surgery to reach and maintain a predetermined desired level of anesthesia or sedation using a closed-loop controller.

14. The system of claim 11 wherein the circuitry further comprises a multistage amplification circuitry and an optimized low frequency shield.