The head-down tilt position decreases vasopressor requirement during hypotension following induction of anaesthesia in patients undergoing elective coronary artery bypass graft and valvular heart surgeries

Previous studies have failed to demonstrate that the head-down tilt position confers benefits in hypovolaemic hypotensive patients. The aim of this study was to evaluate the haemodynamic effect and vasopressor use by this position in hypotensive patients after the induction of general anaesthesia.This prospective randomised study involved 98 patients scheduled for elective cardiac surgery and 40 patients (40.1%) developed hypotension after anaesthesia induction. Upon occurrence of hypotension, patients were randomly allocated to the supine (n = 19) or head-down tilt (n = 21) groups (15° head-down tilt position). Blood pressure, heart rate, cardiac index and stroke volume index were recorded at 1-min interval for 10 min from the occurrence of hypotension. Vasopressors were administered to treat hypotension in both groups.No haemodynamic difference was observed between the supine and head-down tilt groups except for SBP changes from baseline at 1 min (-3.98 ± 6.31 vs. 1.84 ± 8.25%, P = 0.004) and 2 min (1.51 ± 14.34 vs. 9.37 ± 10.57%, P = 0.032). The number of vasopressor administrations and percentage of the patients requiring vasopressors in the supine group were greater than that in the head-down tilt group [median 1 (range 1-5) vs. median 0 (range 0-2), P = 0.002, 19/19 (100%) vs. 10/21 (47.6%), P0.001].The head-down tilt position in hypotensive patients following anaesthesia induction reduced vasopressor requirement by almost one third. Minimal haemodynamic effect may be caused by different vasopressor administrations. This result suggests that the head-down tilt position may enable more stable anaesthesia induction in patients undergoing elective coronary artery bypass graft or valvular heart surgeries.