To Determine the Effect of Varying Time Intervals Between Fentanyl and Propofol Administration on Propofol Requirement for Induction of Anesthesia- A Prospective Observational Study

Abstract

INTRODUCTION:

To determine the effect of varying time intervals between fentanyl and propofol administration on propofol requirement for induction of anesthesia- a prospective observational study

METHOD:

Propofol induction of anesthesia following fentanyl administration should facilitate a smooth induction with a reduction in propofol induction dose and side effects. After obtaining institutional ethical approval, 108 American Society of Anaesthesiologists physical status I–II patients aged 18–65 undergoing elective surgery under general anaesthesia were randomly allocated to one of three groups. In Groups 1, 2, and 3, 2 mcg/kg fentanyl was administered just prior, 3 minutes prior, and 5 minutes prior to propofol induction. Recorded hemodynamic parameters and the required propofol induction dose. Incidence of hypotension, fluid bolus requirement, need for vasopressor administration, incidence of movement or vocalization, and incidence of apnoea post-induction were recorded. The statistical analysis was conducted using SPSS version 24.0 (SPSS Inc., Chicago, Illinois, USA).

RESULTS:

The mean dose of propofol required for induction was highest in Group 1 and lowest in Group 3 (1.75 ± .22 for Group 1, 1.45 ± .36 for Group 2, and 1.25 ± .15 for Group 3.) Incidence of hypotension during induction and need for fluid bolus requirement was significantly higher in Group 1 (19%) and Group 2 (16.7%) than in Group 3 (7.1%) p = 0.001). 1 case among the whole study population required vasopressor post-induction in Group 3. Incidence of vocalization and movement post-induction was higher in group 1 (19%) than in group 2(16.7%) and group 3 (7.1%). Incidence of apnoea post-induction was highest in Group 2 (83.3%) than in Group 1 (76.2%) and Group 3 (59.5%).

CONCLUSION:

Administration of fentanyl five minutes prior to propofol reduces the amount of propofol required and significantly reduces the occurrence of hypotension compared to when given 3 minutes after fentanyl.