Desflurane is known to augment central and systemic sympathetic nervous activity. The present study was aimed at examining the effects of desflurane on cardiovascular responses to intubation.

Seventy-five ASA physical status I patients (aged 35-60 yr) were assigned randomly to receive one of three treatment regimens (n = 25 each): 1 minimum alveolar concentration (MAC) of sevoflurane, 1 MAC of desflurane or 2 MAC of desflurane. Anesthesia was induced with IV thiopental (5 mg/kg), while patients were ventilated with 100% oxygen. Tracheal intubation was facilitated with IV vecuronium (0.12 mg/kg). After intubation, patients received each anesthetic gas in oxygen via a semiclosed anesthesia circuit. Systolic arterial blood pressure (SAP), heart rate (HR) and rhythm, and plasma catecholamine concentrations were measured.

The intubation resulted in immediate increases of SAP and HR in all groups; peak effects occurred within 1 min of the intubation. In addition, 2 MAC desflurane elicited a secondary hemodynamic effect at 3 to 5 min after the intubation. The plasma concentrations of norepinephrine increased significantly when measured at 1 min after intubation in all groups, and returned to preintubation values at 5 min in the 1 MAC desflurane groups, but showed further increases at 5 min in the 2 MAC group.

These results show that 2 MAC desflurane elicits a biphasic hemodynamic response along with an augmented norepinephrine release, where the first appears within 1 min and the second at 3 to 5 min after intubation.