Comparison of the Haemodynamic Effects of Three Different Methods at the Induction of Anaesthesia.

Objective: Haemodynamic variations are inevitable during induction of anaesthetic drugs. The present study investigates the haemodynamic variations of three different drugs (thiopental, propofol, and etomidate) used for induction of general anaesthesia together with fentanyl.

Methods: In a randomized, double-blind study, 45 patients were assigned to one of three groups (n=15 each). Fentanyl 1 μg kg(-1) was injected over 60 sec followed by propofol 2 mg kg(-1) (Group P), thiopentone 6 mg kg(-1) (Group T), or etomidate 0.3 mg kg(-1) (Group E). Noninvasive measurements of systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), and heart rate (HR) was performed on admittance, immediately before the induction of anaesthesia, and 1, 3, and 5 min thereafter. Cardiac output (CO) values were recorded before induction, immediately after the injection of the drug, and at 1 min after the intubation.

Results: In all groups, during the study period, SAP, DAP, MAP, and CO values decreased with respect to time before induction. Following the administration of the induction dose of propofol (Group P), a significantly greater decrease of systolic and diastolic blood pressure was observed with etomidate (Group E) or thiopentone (Group T). Decrease in CO was also more marked with propofol (Group P) than with etomidate (Group E) or thiopentone (Group T).

Conclusion: It's concluded that, in this study, the combination of fentanyl-etomidate is safer than both the groups of fentanyl-propofol and fentanyl-thiopental in terms of providing haemodynamic stability.