Related Experiment Videos
Resting muscle sounds in anesthetized patients
W P McKay1, P H Gregson, B W McKay
1Department of Anesthesia, Dalhousie University, Halifax, Canada. wmckay@the.link.ca
Canadian Journal of Physiology and Pharmacology
|October 31, 1998
Summary
Resting muscles generate measurable low-frequency vibrations. These muscle vibrations significantly decrease with anesthesia and muscle relaxants, confirming their origin.
Area of Science:
- Biomedical Engineering
- Physiology
- Neuromuscular Science
Background:
- Muscle contraction is known to produce low-frequency sound vibrations.
- Unidentified small vibrations are detected in resting muscles.
- The origin of resting muscle vibrations requires further investigation.
Purpose of the Study:
- To investigate the origin of vibrations detected in resting muscles.
- To determine if these vibrations diminish with decreased muscle activity.
- To confirm if resting muscle generates measurable vibrations.
Main Methods:
- Utilized accelerometers to record vibrations from biceps and forearm muscles in 21 subjects.
- Recorded muscle vibrations during four states: lifting a weight, resting awake, induced anesthesia, and paralysis.
- Analyzed recorded signals using Fast Fourier Transform (FFT) to quantify total signal power.
Main Results:
- Total signal power from resting muscles was significantly different across all measured stages (p < 0.05).
- Vibrations significantly diminished in response to anesthesia (thiopental, propofol) and neuromuscular-junction blocking agents.
- The findings were consistent in both biceps and forearm muscle recordings.
Conclusions:
- Resting muscles demonstrably generate measurable low-frequency vibrations.
- These vibrations are of muscular origin, as evidenced by their reduction under anesthesia and paralysis.
- The study provides evidence for subtle physiological activity in quiescent muscle tissue.