HEMODYNAMIC-RESPONSE TO INDUCTION AND INTUBATION

Background: When given as an intravenous bolus for induction of anesth esia, propofol can decrease postintubation hypertension but can also c reate moderate to severe postinduction, preintubation hypotension. The addition of fentanyl usually decreases the postintubation hypertensio n but can increase the propofol-induced preintubation hypotension. The goal of the study was to determine the relation between propofol and fentanyl doses and the hemodynamic changes postinduction, preintubatio n and postintubation. Methods: Twelve groups of 10 patients, ASA physi cal status 1 or 2, first received fentanyl 0, 2, or 4 mu g.kg(-1) and then 5 min later received propofol 2.0, 2.5, 3.0, or 3.5 mg.kg(-1) as an intravenous bolus for induction of anesthesia. Arterial blood press ure was continuously monitored. The trachea was intubated 4 min after propofol administration. Results: The mean decrease in systolic blood pressure after propofol was 28 mmHg when no fentanyl was given, 53 mmH g after 2 mu g.kg(-1) of fentanyl (P < 0.05 vs. no fentanyl), and 50 m mHg after 4 mu g.kg(-1) (P < 0.05 vs. no fentanyl; no statistically si gnificant difference 4 vs. 2 mu g.kg(-1)). There was no statistically significant difference in hemodynamic response to intubation relative to propofol dose. Hemodynamic response to intubation was decreased by the administration of fentanyl; the mean increase of systolic blood pr essure after intubation was 65 mmHg from preintubation value without f entanyl, 50 mmHg after 2 mu g.kg(-1), and 37 mmHg after 4 mu g.kg(-1) (P < 0.05 for 2 and 4 mu g.kg(-1) vs. no fentanyl and for 4 vs. 2 mu g .kg(-1)). Hemodynamic changes postintubation were not statistically di fferent with increasing doses of propofol. Conclusions: Hemodynamic ch anges after induction with propofol or propofol/fentanyl, pre- or post intubation, are not modified when the propofol dose is increased from 2 to 3.5 mg.kg(-1). Maximal hypotension preintubation occurs with a fe ntanyl dose of 2 mu g.kg(-1), whereas the magnitude of postintubation hypertension is significantly decreased with an increase in the fentan yl dose to 4 mu g.kg(-1).