Electromyographic and mechanical twitch responses following suxamethonium administration.

Electromyographic and mechanical evoked twitch responses at the hand were observed simultaneously following suxamethonium. The intensity of neuromuscular blockade was assessed by comparison with their control heights of the responses obtained from both the force of thumb adduction and from the compound electromyogram (EMG). Surface electrodes placed dorsally over the lateral hand provided two EMG signals, one of which was assessed in terms of its amplitude, the other as the rectified and integrated energy envelope. While the mechanical and electrical events were roughly in agreement there was better conformity between the two EMG techniques in the assessment of paralysis.