Abstract: AIM: To investigate the neuromuscular pharmacodynamics of rocuronium on thymectomy in myasthenia gravis (MG) patients. METHODS: Twenty-three Ⅰ-Ⅱa MG patients undergoing elective thymectomy (Group M) since January 2006 were studied. Another twenty non-MG patients undergoing other elective surgery were included as control group (Group C). All patients were performed under total intravenous anesthesia by tracheal intubation, given a loading dose of rocuronium 0.6 mg/kg as anesthesia induction. Neuromuscular transmission was monitored by measuring the twitch tension of the adductor pollicis muscle. And the heart rate variability (HRV) was analyzed during the surgery. RESULTS: Anesthesia and surgery were carried out successfully without any adverse reaction. The analysis revealed that the MAP, HR, HRV, LF/HF had no significant difference between the two groups at all time points. The onset time was significantly shorter in group M than that in the group C (P<0.05). There were no significant group differences in the recovery time of T₁ to 25%, the recovery time of T₁ to 50%, and the recovery indices (interval, 25%-75%). CONCLUSION: The results show that rocuronium, as anesthesia induction at a dose of 0.6 mg/kg, has a shorter muscle relaxants onset time and a small influence on the maintaining time. It also can result in fewer perioperative complications and provide optimal operating conditions.It is a safe anaesthesia method in thymectomy of Ossermen Ⅰ-Ⅱa MG patients with anesthesia induction by injecting rocuronium.

Key words: Androstanol, Myasthenia gravis, Neuromuscular blockade, Heart rate variability