Predictors of extubation outcomes following myasthenic crisis

Objective Myasthenic crisis (MC) is considered the most severe adverse event in patients with myasthenia gravis. The present retrospective study was performed to evaluate the predictors of clinical outcomes in patients with MC. Methods The medical charts of 33 patients (19 women, 14 men) with 76 MC attacks from 2002 to 2014 were retrospectively reviewed. Early extubation (≤7 days) and prolonged ventilation (>15 days) during the MC were used to assess patient outcomes. Results Among the 33 patients, 24 (72.7%) had positive acetylcholine receptor antibody test results and 20 (60.6%) experienced recurrent MC attacks (≥2 episodes) during follow-up (median 83.6 months, range 1.5-177 months). Plasma exchange during an MC was significantly associated with early extubation. Male sex, older age (>50 years), atelectasis, and ventilator-associated pneumonia significantly contributed to prolonged ventilation. In 22 patients who underwent thymectomy, both the duration between MC attacks and the mean number of MC attacks were significantly reduced after surgery. Conclusions Plasma exchange during MC attacks was found to be important for early extubation; older patients and those with atelectasis or ventilator-associated pneumonia were more vulnerable to prolonged ventilation. Thymectomy may be useful to prevent recurrence of MC.