Priming with Atracurium

Priming with atracurium was evaluated by dividing 39 patients into 2 groups. All received 0.2 mg IV glycopyrrolate and fentanyl, 50 μg IV. Group 1 received saline, group 2 received 0.06 mg/kg atracurium and a stop watch was started. After 3.5 min the patients were asked to lift their heads and maximum negative inspiratory pressure (MIP) was measured. Anesthesia then commenced with thiorpental and a twitch monitor was applied to the ulnar nerve. At 5 min group 1 received 0.36 mg/kg atracurium and group 2 was given 0.30 mg/kg atracurium. At 6.5 min intubation was accomplished in all but one patient in group 1 and all but one in group 2. Mean T4/T1 ratios at 90 sec were 0.73 in group 1 and 0.51 in group 2. This difference was statistically significant (P < 0.001). Bucking on the endotracheal tube occurred in 72% of patients in group 1 and 62% of those in group 2 (not significant). Intubating conditions were “excellent” in 56% of those in group 1 and 75% in group 2 (not significant). “Good” conditions were seen in 33% of group 1 and 15% of group 2 patients (not significant). “Fair” conditions were noted in 6% of patients in group 1 and 5% of group 2 patients (not significant). The time to maximum twitch depression was 11.3 min and 11.5 min in groups 1 and 2 respectively (not significant). All patients in group 1 could sustain head lift whereas four patients in group 2 could not (not significant). A decrease in MIP was noted in 38% of patients in group 2, but MIP was not decreased in those in group 1. This difference was statistically significant (P < 0.005). We conclude that priming with atracurium, although providing a small improvement in T4/T1 ratio at intubation, does not significantly improve intubating conditions. It is complex, time consuming, is not well tolerated, and may put patients at risk for aspiration.