Publications

Background and Aims: Obese patients are more vulnerable to residual neuromuscular block (NMB)
and its associated complications in the post-operative period. This study was carried out to
compare neostigmine induced reversal of vecuronium in normal weight, overweight and obese
female patients, objectively using neuromuscular (NM) monitoring. Methods: Twenty female
patients each belonging to normal weight, overweight and obese, based on body mass index,
requiring general anaesthesia were recruited for this prospective cross sectional study. NMB
was induced with vecuronium (0.1 mg/kg) dose based on patient’s real body weight (RBW) and
monitored using acceleromyographic train of four (TOF). All patients received neostigmine 40
μg/kg and glycopyrrolate 10 μg/kg at 25% of spontaneous recovery of first twitch height (T1) of
TOF (DUR 25%) and were allowed to recover to TOF ratio of 0.9. Statistical analysis was done
using analysis of variance test. Results: Recovery of TOF ratio to 0.5 was comparable in all
three groups. Recovery of TOF ratio to 0.7 was delayed in obese (9.82 ± 3.21 min) compared
with normal weight group (7.50 ± 2.52 min). Recovery of TOF to 0.9 was significantly delayed
in both overweight (12.18 ± 4.29 min) and obese patients (13.78 ± 4.30 min). DUR 25% was
significantly longer in overweight (mean, standard deviation [range]; 30.10 [19–40 min]) and obese
(28.8 [12–45 min]) compared with normal weight patients (22.75 [16–30 min]). Conclusion: In
overweight and obese patients, when vecuronium induction dose is based on RBW, neostigmine
induced recovery of NMB is delayed in late phases (TOF 0.7–0.9), which may result in vulnerability
for associated complications of incomplete recovery. Ensuring safe recovery thus requires objective
NM monitoring.
Key words: Neostigmine, neuromuscular monitoring, obesity, vecuronium bromide