A single dose of esmolol blunts the increase in bispectral index to tracheal intubation during sevoflurane but not desflurane anesthesia

Abstract

Activation of the peripheral nerve system by endotracheal intubation is accompanied by an increase in bispectral index (BIS). Esmolol produces a dose-dependent attenuation of the adrenergic response to endotracheal intubation. Desflurane increases sympathetic nerve activity and plasma norepinephrine relative to sevoflurane. The authors hypothesized that esmolol might blunt the BIS response to endotracheal intubation more during sevoflurane anesthesia than desflurane anesthesia. In this double blind, randomized study, after the induction of anesthesia, patients were mask-ventilated with either sevoflurane or desflurane (end-tidal 1 minimum alveolar concentration) and received normal saline or esmolol (0.5 mg/kg) 1 minute before intubation (sevoflurane-control, sevoflurane-esmolol, desflurane-control, and desflurane-esmolol groups, n=20/group). BIS, mean arterial pressure, and heart rate were measured before the induction of anesthesia (awake), before esmolol injection (time point -1), immediately before intubation (time point 0), and every minute for 5 minutes after tracheal intubation (time point 1 to 5). Compared with preintubation, esmolol attenuated the increase in BIS at 1 minute after intubation during sevoflurane anesthesia (5.1% for esmolol and 31.7% for control) but not during desflurane anesthesia (28.6% for esmolol and 30.8% for control). Mean arterial pressure and heart rate increased after intubation in all groups but the changes were greater in the control groups than the esmolol groups. In conclusion, a single dose of esmolol blunted the increase in BIS to tracheal intubation during sevoflurane but not desflurane anesthesia.