Localized hypothermia influences assessment of recovery from vecuronium neuromuscular blockade

[Delay of clinical recovery from paralysis induced by atracurium: comparison between orbicularis oculi and adductor pollicis]

OBJECTIVE

To compare with train-of-four stimulation the delays of the beginning of the spontaneous recovery of the orbicularis oculi and of the adductor pollicis after profound neuromuscular blockade with atracurium.

STUDY DESIGN

Prospective, comparative open study.

PATIENTS AND METHODS

Twenty-eight physical class ASA 1 and 2 patients under general anaesthesia (propofol, N2O, fentanyl) and profound neuromuscular blockade with atracurium. Train-of-four stimulation, every 10 s, of the ulnar nerve at the wrist (for assessing by tactile means the response of the adductor pollicis) and of the temporal branch of the facial nerve (for assessing visually the response of the orbicularis oculi). On each site, measurement of the delay between the end of the maintenance of deep neuromuscular blockade (last dose of atracurium) and the beginning of the recovery (first response to train-of-four stimulation).

RESULTS

In each case, the recovery of the orbicularis oculi began earlier than the recovery of the adductor pollicis (26 +/- 9 min vs 34 +/- 9 min, P < 0.001). The delays of recovery at each site were strongly correlated (r = 0.87; P < 0.001) but the time lag between the responses varied greatly: 1 to 21 min, mean: 8 +/- 5 min, coefficient of variation: 56.6%.

CONCLUSION

The orbicularis oculi should not be monitored alone for assessment of recovery from profound neuromuscular blockade by atracurium, as it predicts poorly the time of the recovery of the adductor pollicis.