Acceleromyograph

An acceleromyograph is a piezoelectric myograph, used to measure the force produced by a muscle after it has undergone nerve stimulation. Acceleromyographs are most commonly employed after the use of anesthetics to test for residual muscle weakness in the patient.

Patients who undergo anesthesia may receive a drug that paralyzes muscles, improving operating conditions for the surgeon. Longer-acting drugs have higher residual blockade in the PACU or ICU than shorter acting drugs. Different clinical tests to measure or exclude evidence of residual muscle weakness have been described. Small degrees of muscle blockade can only accurately be measured by the use of quantitative neuromuscular monitoring. Specifically, the observer cannot reliably measure muscular fade when train-of-four ratios are between 0.4 and 0.9.

Acceleromyographs measure muscle activity using a miniature piezoelectric transducer that is attached to the stimulated muscle. A voltage is created when the muscle accelerates and that acceleration is proportion to force of contraction. Acceleromyographs are more costly than the more common twitch monitors, but have been shown to better alleviate residual blockade and associated symptoms of muscle weakness, and to improve overall quality of recovery.

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