Haemodynamic effects of anaesthesia induction with etomidate/remifentanil followed by sevoflurane/remifentanil balanced anaesthesia

Background: Hypotension is a common side effect of induction of general anaesthesia, however, the pathophysiology and mechanisms of anaesthesia-induced hypotension are yet not fully understood. The aim of this prospective observational study was to investigate the different haemodynamic effects of induction of anaesthesia with etomidate / remifentanil and of continuation of anaesthesia with sevoflurane / remifentanil. Methods: In 18 patients who underwent extended haemodynamic monitoring by means of the transpulmonary thermodilution method for major surgery, cardiac index (CI), global end-diastolic volume index (GEDI), maximum rate of aortic pressure increase (dPmx), and further surrogate parameters of cardiac contractility were recorded in addition to basic haemodynamic parameters. Measurements were taken before induction of anaesthesia (T1), after induction (T2), and after addition of 0.7 MAC sevoflurane during balanced anaesthesia (T3). Results: After induction of anaesthesia there was a small but significant decrease in mean arterial blood pressure (MAP) (-11 %), CI (-11 %) and GEDI (-7 %). Systemic vascular resistance (SVRI), heart rate (HR) and dPmx remained un-changed. Balanced anaesthesia with sevoflurane/remifentanil was associated with an additional decrease of MAP by 25 %. A decrease in HR (-15 %), SVRI (-19 %), parameters of contractility, and a further decrease in CI (-13 %) were observed. Conclusion: Induction of anaesthesia with etomidate / remifentanil was associated with a comparatively small decre-ase in MAP due to a small decrease in cardiac index and preload. Continuation of anaesthesia by a balanced anaesthesia technique with sevoflurane / remifentanil, however, caused a further pronounced decrease in MAP resulting from a combined decrease in resistance and cardiac contractility, but not cardiac preload.