Electromyographic assessment of neuromuscular block at the gastrocnemius muscle

We have assessed neuromuscular block electromyographically at thegastrocnemius muscle and compared it with that at the abductor digitiminimi muscle in 60 adult patients undergoing cervical spine surgery undergeneral anaesthesia. All patients were in the prone position. Aftervecuronium 0.2 mg kg-1, times to onset of neuromuscular block at thegastrocnemius and abductor digiti minimi muscles were mean 147 (SD 24) and145 (14) s, respectively (ns). Times to return of the first response of thepost-tetanic count (PTC1) at the gastrocnemius and abductor digiti minimimuscles were 27.7 (5.6) and 37.0 (5.9) min, respectively (P = 0.0001).Times to return of the first response of the train-of-four (TOF) at thegastrocnemius and abductor digiti minimi muscles were 41.0 (9.1) and 49.9(8.7) min, respectively (P = 0.01). Recovery of PTC, T1/T0 and TOF ratio atthe gastrocnemius muscle were significantly faster than at the abductordigiti minimi muscle.