A Study of the Effect of Varying Time Intervals between Fentanyl and Propofol on Propofol Requirement for Induction of General Anesthesia: A Randomized Prospective Controlled Study

BACKGROUND: Propofol is widely used for the induction of general anesthesia but is associated with dose-dependent hypotension. Fentanyl, when administered before propofol, may reduce the propofol dose requirement and mitigate hemodynamic instability. OBJECTIVE: To evaluate the effect of varying time intervals between fentanyl and propofol administration on propofol dose requirement for induction and to assess associated hemodynamic responses. MATERIALS AND METHODS: This randomized controlled study enrolled 150 American Society of Anesthesiologists I-II patients aged 18-60 years scheduled for elective surgery under general anesthesia. Patients were allocated into three groups (n = 50 each): Group 1 received propofol immediately after fentanyl (2 μg/kg intravenous), Group 2 after 3 min, and Group 3 after 5 min. Propofol was titrated until loss of verbal response. Hemodynamic parameters were recorded at baseline, postfentanyl, during induction, and postintubation. Incidence of hypotension, movements, bucking, and vocalization were noted. RESULTS: Group 3 required significantly less propofol (67.6 ± 16.36 mg) than Group 2 (104.6 ± 21.2 mg) and Group 1 (137.8 ± 12.41 mg) (P < 0.001). The incidence of hypotension was lowest in Group 3 (3%) compared with Group 2 (21%) and Group 1 (45%) (P < 0.001). Group 3 also showed better attenuation of the intubation response and fewer adverse movements. CONCLUSION: Administering propofol 5 min after fentanyl significantly reduces induction dose requirements and improves haemodynamic stability during induction and intubation.