Comparison of two induction regimens using or not using muscle relaxant: impact on postoperative upper airway discomfort^†

Background

Muscle relaxants facilitate tracheal intubation, but they are often not used for short peripheral surgical procedures. The consequences of this practice on the upper airway are still a matter of controversy. We therefore compared the incidence of post-intubation symptoms in a randomized study comparing patients intubated with or without the use of a muscle relaxant.

Methods

A total of 300 adult patients requiring tracheal intubation for scheduled peripheral surgery were randomly assigned in a double-blind study to an anaesthetic protocol that either included or did not include a muscle relaxant (rocuronium). The primary end-point was the rate of post-intubation symptoms 2 and 24 h after extubation. The secondary end-points were the intubation conditions score (Copenhagen Consensus Conference), the rate of difficult intubations (Intubation Difficulty Scale), and the incidence of adverse haemodynamic events.

Results

Post-intubation symptoms were more frequent in patients intubated without the use of a muscle relaxant, whether 2 h (57% vs 43% of patients; P < 0.05) or 24 h (38% vs 26% of patients; P < 0.05) after extubation. Intubation conditions were better when the muscle relaxant was used. In patients intubated without a muscle relaxant, difficult intubation was more common (12% vs 1%; P < 0.05), as were arterial hypotension or bradycardia requiring treatment (12% vs 3% of patients; P < 0.05).

Conclusions

The use of a muscle relaxant for tracheal intubation diminishes the incidence of adverse postoperative upper airway symptoms, results in better tracheal intubation conditions, and reduces the rate of adverse haemodynamic events.