Comparison of adjuvant anesthetics for propofol induction.

Purpose: Fentanyl was compared with nitrous oxide/sevoflurane as an adjuvant anesthesia to propofol during induction.

Methods: Two-hundred sixty-three patients of American Society of Anesthesiologists physical status 1 or 2 undergoing minor surgery were randomly divided into two groups. Group F patients (n = 125) received 2 microg x kg(-1) fentanyl and 1.8 mg x kg(-1) propofol, and were ventilated by mask with oxygen. Group S patients (n = 138) received 1.8 mg x kg(-1) propofol, followed by inhalation of 4% sevoflurane in N2O (41 x min(-1)) and oxygen (21 min(-1)) by mask. The trachea was intubated exactly 2, 3, 4, or 5 min after injection of 0.1 mg x kg(-1) vecuronium, and the conditions of endotracheal intubation were scored according to the patients' responses to laryngoscopy and endotracheal intubation. Systolic blood pressure (SBP) and heart rate (HR) were measured before and after endotracheal intubation. The cost of anesthetics was also calculated.

Results: No significant differences in SBP were observed between the groups throughout the induction period. HR did not change from preanesthetic values in group F. In contrast, HR in group S patients increased by 9-18 beats x min(-1) (bpm) after inhalation of N2O/sevoflurane and further increased by 17-21 bpm following endotracheal intubation. Significant differences in HR were noticed between the groups (P < 0.001). The conditions of endotracheal intubation were similar in the two groups and were satisfactory when mask ventilation exceeded 3 min. Fentanyl was less expensive than sevoflurane/N2O anesthesia when mask ventilation exceeded 3 min.

Conclusion: From the standpoints of hemodynamics and drug cost, fentanyl is preferable to N2O/sevoflurane inhalation as an adjuvant to propofol during induction, because mask ventilation for more than 3 min was required for satisfactory endotracheal intubation.