[Influence of gender on the intubation conditions with rocuronium]

There is increasing evidence for gender differences in the pharmacokinetics and pharmacodynamics of anaesthetic drugs and neuromuscular blocking agents, e.g. rocuronium (Roc). Females require 30% less Roc than males to achieve the same degree of neuromuscular block and onset times are shorter. However, whether this leads to an improvement of the intubation conditions in females is unclear.

After approval of the ethics committee 60 female and 60 male patients were each randomised into 2 groups to receive 0.6 mg/kg body weight Roc or 1.0 mg/kg succinylcholine (Sux; control group). Induction: thiopentone (5 mg/kg), fentanyl (3 microg/kg) then Roc (Roc groups) or Sux (Sux groups) and tracheal intubation after 60 s. Time to intubation, glottic exposure and intubating conditions were assessed.

Men were significantly larger and heavier (p<0.001) than women, but the body mass index was comparable (ns). Number of attempts, time to intubation, and Cormack grades were comparable (ns). However, the rate of clinically acceptable intubation conditions was significantly higher in the female compared to the male Roc group: 80% vs 47%, p<0.05. The incidence of clinically acceptable intubation conditions in the female Roc and Sux groups were similar (80%).

The intubation conditions after Roc were significantly better in women than in men. The differences were Roc-related and did not occur in the control groups.