COMMUNICATION WITH AND CONSCIOUSNESS-ASSESSMENT OF ANESTHETIZED SURGERY PATIENTS

• US 20100256515A1
• Filed: 04/01/2010
• Published: 10/07/2010
• Est. Priority Date: 04/03/2009
• Status: Abandoned Application

• Current Assignee: Marc J. Egeth
• Original Assignee: Marc J. Egeth
• Inventors: Egeth, Marc J.
• Application Number:
  US12/752,739
• Publication Number:
  US 20100256515A1
• Time in Patent Office: Days
• US Class Current: 600/544
• 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 5/4821 Determining level or depth of anaesthesia A61B5/1106 takes precedence

Abstract

In one embodiment, prior to undergoing surgery, a patient is trained in the use of an anesthesia-awareness detection (AAD) system to produce an observable output by attempting to move a muscle. The AAD system includes an electromyographic (EMG) signal monitor. While undergoing surgery, the patient is anesthetized with a sedative and a paralytic. During surgery, if the surgical team wishes to asses the consciousness state or communicative ability of the patient, then the surgical team asks the patient to move the muscle. If the patient is unable to speak due to the paralytic but is aware and attempts to comply, then the attempt is detected by the AAD system, which provides a corresponding output to inform the surgical team, which may take appropriate action to ask additional questions of the patient and/or address the patient'"'"'s anesthesia awareness.

Claims

1. An anesthesia-awareness detection (AAD) system comprising:

an output module adapted to be activated to generate at least one of an audible output and a visible output;

a muscle-motion sensor adapted to (i) detect one or more muscle-motion signals produced by an anesthetized patient and (ii) generate a sensor output signal corresponding to the one or more muscle-motion signals; and

a signal processor adapted to (i) process the sensor output signal to determine whether or not the one or more muscle-motion signals are volitional by the patient and (ii) activate the output module if the signal processor determines that the one or more muscle-motion signals are volitional indicating that the patient is aware.

2. The system of claim 1, wherein the muscle-motion sensor comprises a set of one or more surface electrodes adapted to:

be placed over a muscle of the patient;

detect electromyography (EMG) signals generated by the muscle; and

generate the sensor output signal to indicate the detected EMG signals.

3. The system of claim 2, wherein the set of surface electrodes comprises two or more surface electrodes arranged as an n-by-m grid.

4. The system of claim 2, wherein the set of surface electrodes is further adapted to:

be placed on a patient'"'"'s forehead;

detect electroencephalogram (EEG) signals; and

generate an EEG output signal to indicate the detected EEG signals, wherein the EEG output signal is not the sensor output signal.

5. The system of claim 1, wherein the muscle-motion sensor comprises one or more accelerometers adapted to:

be placed over a muscle of the patient;

detect movements of the muscle; and

generate the sensor output signal to indicate the detected movements of the muscle.

6. The system of claim 1, wherein the muscle-motion sensor comprises a detector adapted to:

be placed proximate to a motor neuron associated with a muscle;

detect a neuromuscular (NM) signal generated by at least one of (i) the release of neurotransmitters by the motor neuron and (ii) the transmission of an impulse along the motor neuron; and

generate the sensor output signal indicative of the detected NM signal.

7. The system of claim 1, wherein the one or more muscle-motion signals include at least two of (i) an electromyography (EMG) signal, (ii) a neuromuscular (NM) signal, and (iii) an accelerometer-detectable muscle-motion signal.

8. The system of claim 1, wherein the muscle-motion sensor comprises a plurality of probe electrodes adapted to:

be inserted into a muscle of the patient;

detect electromyography (EMG) signals generated by the muscle; and

generate the sensor output signal to indicate the detected EMG signals.

9. The system of claim 1, wherein the signal processor is adapted to:

calculate a metric based on the sensor output signal; and

determine that the patient is aware if the metric exceeds a threshold that was set during a pre-operative preparation of the patient.

10. The system of claim 1, further comprising an automated consciousness-monitoring system adapted to determine and indicate that the patient is one of (i) aware and (ii) likely to soon become aware, wherein the determination is not based on muscle-motion signals produced by the patient.

11. The system of claim 1, wherein the signal processor is adapted to:

detect a plurality of particular patterns in the sensor output signal; and

activate the output module differently for each different detected particular pattern.

12. the system of claim 11, wherein the processor is programmable to define the plurality of particular patterns and the corresponding different output-module activations.

13. A method for detecting anesthesia awareness comprising:

detecting one or more muscle-motion signals produced by an anesthetized patient;

generating a sensor output signal corresponding to the one or more muscle-motion signals;

processing the sensor output signal to determine whether or not the one or more muscle-motion signals are volitional by the patient is aware; and

activating an output module if the signal processor determines that the one ore more muscle-motion signals are volitional indicating that the patient is aware, wherein the output module generates at least one of an audible output and a visible output if activated.

14. The method of claim 13, wherein:

the method further comprises placing a plurality of surface electrodes over a muscle of the patient, the surface electrodes adapted to detect electromyography (EMG) signals;

the detecting comprises detecting EMG signals generated by the muscle; and

the sensor output signal indicates the detected EMG signals.

15. The method of claim 13, wherein:

the method further comprises placing one or more accelerometers over a muscle of the patient adapted to detect movements of the muscle;

the detecting comprises detecting accelerometer-detectable movements of the muscle; and

the sensor output signal indicates the detected movements of the muscle.

16. The method of claim 13, wherein:

the method further comprises placing one or more muscle-motion sensor proximate to a motor neuron associated with a muscle, the sensor adapted to detect neuromuscular (NM) signals;

the detecting comprises detecting NM signals generated by at least one of (i) the release of neurotransmitters by the motor neuron and (ii) the transmission of an impulse along the motor neuron; and

the sensor output signal indicates the detected NM signal.

17. The method of claim 13, wherein the processing further comprises:

calculating a metric based on the sensor output signal; and

determining that the patient is aware if the metric exceeds a threshold that was set during a pre-operative preparation of the patient.

18. The method of claim 13, wherein the processing further comprises:

detecting a plurality of particular patterns in the sensor output signal; and

activating the output module differently for each different detected particular pattern.

19. The method of claim 18, further comprising programming a processor to define the plurality of particular patterns and the corresponding different output-module activations.

20. The method of claim 13, further comprising administering anesthetics to the patient such that the patient retains the ability to at-least-partially furrow his or her brow while otherwise substantially immobilized.

21. A method comprising:

anesthetizing a patient;

then determining to assess the consciousness of the anesthetized patient;

then asking the anesthetized patient to perform an activity that would generate a detectable muscle-motion signal;

then observing an output module of an anesthesia-awareness system to determine whether a corresponding muscle-motion signal is detected;

then determining that;

the patient is aware if the corresponding muscle-motion signal is detected; and

the patient is probably not aware if the corresponding muscle-motion signal is not detected; and

then administering additional sedative to the patient if it was determined that the patient is aware.