Effect of varying time intervals between fentanyl and propofol administration on propofol requirement for induction of anaesthesia: Randomised controlled trial

Abstract

Background and Aims: Administration of fentanyl before induction of anaesthesia with propofol should facilitate smooth induction, with a reduction in induction dose of propofol and its side effects. This study was designed to examine the effect of varying intervals between fentanyl and propofol administration on the dose of propofol required for induction of anaesthesia. Methods: After institutional ethical clearance, 129 American Society of Anesthesiologists physical status I--II patients, aged 18--65 years, undergoing elective surgery under general anaesthesia were randomised into three groups. Fentanyl 2 mcg/kg was administered immediately prior to, 3 and 5 min before induction with propofol in Groups 1, 2, and 3, respectively. Requirement of propofol induction dose and haemodynamic parameters was recorded. Statistical analysis was performed using software SPSS (SPSS Inc., Chicago, Illinois, USA). Results: Total dose of propofol required for induction was highest in Groups 1 and lowest Group 3 (Group 1 vs. 2 vs. 3: 86.28 ± 21.12 vs. 71.67 ± 21.68 vs. 59.98 ± 20.35 mg, P< 0.00001). Dose of propofol required per kg body weight was significantly higher in Group 1 (1.41 ± 0.34 mg/kg) compared to both Group 2 (1.14 ± 0.38 mg/kg) and Group 3 (0.97 ± 0.32 mg/kg) (P < 0.00001). Incidence of hypotension during induction was significantly lower in Group 3 (14%) and Group 2 (17.1%) than in Group 1 (35.6%; P= 0.03). Conclusion: Administering fentanyl 5 min prior to propofol causes marked reduction in the dose requirement of the latter along with a significantly decreased incidence of hypotension during induction.

Keywords

• Anaesthesia
• fentanyl
• propofol