Effects of small peripheral temperature changes on the evoked baseline electromyographic response

Abstract

The electrically evoked EMG-response is sensitive to even small changes in temperature at the measurement site. Therefore, when applying the evoked EMG in neuromuscular studies, peripheral skin or muscle temperatures need to be monitored, and attempts to stabilise the temperature of the monitored muscles should be made.

Area under the curve and amplitude of the compound motor action potential are clinically interchangeable quantitative measures of neuromuscular block: a method comparison study

“…However, there would be no effect on the TOFR because the fractional increase would occur in both the numerator (T 4 ) and the denominator (T 1 ), cancelling the effect. In 24 patients undergoing ophthalmic surgery under general anaesthesia, Santanen and Paloheimo 35 studied the effect of deliberate cooling and re-warming of the hand on the AUC T 1 response from the first dorsal interosseous muscle after every 1-min TOF stimulation of the ulnar nerve at the wrist. Similar to the findings in the cat, 34 each 1°C change in muscle temperature (measured with a myocardial temperature sensor inserted into the belly of the muscle) resulted in an 8.0% ( sd 0.8%) difference in the T 1 response compared with its stable baseline value.…”

Good clinical research practice (GCRP) in pharmacodynamic studies of neuromuscular blocking agents III: The 2023 Geneva revision

“…Any change in stimulus pattern using acceleromyography (AMG) and mechanomyography (MMG) after stability has been achieved is likely to result in a change in the twitch height amplitude. This effect is less pronounced with EMG, although EMG amplitude may increase by 2%–3% per °C decrease in the surface temperature, while the integrated EMG area may vary by 4%–8% per °C 35,36 . For these reasons, studies using EMG monitoring should specify the method for quantification of the compound muscle action potential (cMAP) (i.e., integrated area vs. amplitude vs. duration of cMAP).…”