Effects of Lidocaine, Verapamil and Their Mixture on Neuromuscular Blockade

Kim, Sung Yell; Kim, Jin Soo; Lee, Jeong Seok; Cho, Su Hyun; Kim, Soon Im; Kwak, Soo Dal; Kang, Kyu Sik

Abstract

BACKGROUND: Lidocaine, verapamil or a lidocaine-verapamil mixture was effectively applied for blunting extubation during recovery from anesthesia. However, these drugs can enhance neuromuscular blockade and cardiovascular depression. We investigated the neuromuscular and the cardiovascular effect of lidocaine, verapamil or a lidocaine-verapamil mixture before extubation in the recovery from anesthesia.
METHODS
We studied ninety nine healthy adult patients (ASA class I or II), excluding the patients with cardiovascular diseases and with factors affecting neuromuscular function. Induction of anesthesia was performed with thiopental sodium 5 mg/kg and fentanyl 0.1 mg, and maintained with O2-N2O (50%)-enflurane (2%). Supramaximal single twitch stimuli (0.1 Hz) were applied to the ulnar nerve and the twitch response of the adductor pollicis was recorded by the Gould TA 240 recorder via a 2 kg Load Cell Strain Gauge modification. After stabilization of the twitch response, mivacurium (0.16 mg/kg) or vecuronium (0.1 mg/kg) was administered intravenously and endotracheal intubation was performed. Twitch heights were spontaneously recovered without a reversal agent from the neuromuscular blockade as a spontaneous group. Pyridostigmine 10 mg and glycopyrrolate 0.2 mg were administered intravenously around the time of 10% recovery of baseline twitch height as a reversal recovery group. At the time of 100% recovery of twitch height, train of four (TOF) stimuli was applied and then lidocaine, verapamil or a lidocaine-verapamil mixture was administered intravenously in both groups. Maximum depression of twitch height and the TOF ratio at this point, recovery index (RI) measured, and mean arterial pressure and pulse rates were measured before and at 2, 5, 10, 20 and 30 min. after the lidocaine-verapamil mixture administration.
RESULTS
Twitch heights were depressed slightly after lidocaine, verapamil or a lidocaine-verapamil mixture administration; however, there were no significant differences to compare with the control. TOFratios were unchanged after lidocaine, verapamil or lidocaine-verapamil administration compared at the 100% twitch height recovery. RI indices were not significant between groups in reversal recovery or in spontaneous recovery. Mean arterial pressure was reduced significantly until 20 min after a lidocaine-verapamil mixture administration, pulse rates were increased at 2 min only after a lidocaine- verapamil mixture administration.
CONCLUSIONS
Twitch height and TOF ratios were not affected by clinical doses of lidocaine, verapamil or a lidocaine-verapamil mixture. However, mean arterial pressure and pulse rates were changed significantly by a lidocaine-verapamil mixture.