ABSTRACT
BACKGROUND AND AIMS: Previous studies suggest that administration of vecuronium based on total body weight rather than ideal body weight (IBW) in obesity results in overdosing with prolonged recovery times. We hypothesised that larger doses of neostigmine could result in faster recovery in obese patients administered vecuronium based on total body weight. METHODS: Forty-five obese American Society of Anesthesiologists' II patients undergoing elective surgery under general anaesthesia were randomised into 3 groups to receive neostigmine 30, 40 and 50 µg/kg. Following induction, patients were paralysed with vecuronium 0.1 mg/kg based on total body weight. Reversal was achieved with neostigmine based on the patient's group, and time to train-of-four (TOF) ratios of 0.5, 0.7 and 0.9 measured. The primary outcome variable was time to achieve TOF ratio >0.9. RESULTS: Neostigmine 50 µg/kg achieved faster recovery to TOF 0.7 than neostigmine 30 and 40 µg/kg. There was no significant difference in recovery times to TOF 0.7 in patients receiving either 30 or 40 µg/kg of neostigmine. However, neostigmine 40 µg/kg attained TOF ratio 0.9 faster than 30 µg/kg. We did not note a significant difference between the 40 and 50 µg/kg dose with regard to recovery of TOF to 0.9. CONCLUSION: Facilitated recovery from neuromuscular blockade to TOF of 0.7 was faster with neostigmine 50 µg/kg compared to 40 or 30 µg/kg. Recovery to TOF ratio of 0.9 was not significantly different with 40 or 50 µg/kg doses although such time was faster as compared to 30 µg/kg dose.
