The effect of succinylcholine on the recovery of atracurium-induced neuromuscular blockade

At the end of abdominal surgery, a brief but profound neuromuscular blockade may be needed to facilitate closure of abdominal wall. Succinylcholine (Sch) was the agent used in this regard before. This study was undertaken to observe the effect after administration of Sch (1 mg/kg) at various levels of recovery from atracurium. 40 ASA I or II patients undergoing elective surgery were randomly assigned to one of four groups with 10 in each. Anesthesia was induced with thiopental 5 mg/kg and Sch 1.5 mg/kg i.v., and maintained with 0.7% isoflurane (end-tidal concentration) and 50% N2O in O2 The electromyographic response of the hypothenar muscle was recorded in response to supramaximal train-of-four stimuli delivered to the ulnar nerve at 20 s intervals using a relaxograph (Datex). Control records were obtained after induction of anesthesia. When the first twitch (T1) had recovered above 50% from the intubating dose of Sch, atracurium 0.5 mg/kg was administered. Spontaneous recovery of T1 was observed. Patients in group I received 1 mg/kg of Sch, when T1 returned to 20% and those in groups II, III, and IV received the same dose of Sch when T1 returned to 40%, 60% or 80% of control respectively. The response was observed at 20s intervals for at least 5 min after the administration of Sch. It was regarded as effective response if the T1 returned to less than 5% of control.(ABSTRACT TRUNCATED AT 250 WORDS)