The Onset Time of Atracurium Is Prolonged in Patients with Sickle Cell Disease

BACKGROUND: Patients with sickle cell disease (SCD) frequently undergo surgery during their lifetime. Patients with SCD are considered at greater risk of perioperative complications than otherwise healthy patients and require meticulous anesthetic management. The pharmacodynamics of anesthetics may be altered in patients with SCD due to microcirculatory abnormalities or anemia. METHODS: In this study, we assessed the pharmacodynamics of a single dose of atracurium (0.5 mg/kg) by mechanomyography in 13 patients with SCD and in 17 control patients. RESULTS: The time between atracurium administration and 90% twitch height depression (onset time) was longer in SCD patients (mean ± SD) 323 ± 124 s than in controls 165 ± 36 s (P < 0.01). Unsatisfactory intubation conditions at 3 min after atracurium administration were observed in 5/13 patients with SCD and 1/17 control patients (P < 0.05). The duration of action of atracurium in patients with SCD was similar to that of control patients. The time to spontaneous return of the train-of-four ratio to 0.9 was 101 ± 24 min in control patients and did not differ 93 ± 24 min in patients with SCD. CONCLUSION: Delayed onset time, together with unchanged duration of the neuromuscular blocking effect of atracurium, may be explained by an increased distribution volume of atracurium in patients with SCD. Our results suggest that monitoring of neuromuscular block may guide the time of tracheal intubation in patients with SCD.