Background anaesthetic agents do not influence the impact of arginine vasopressin on haemodynamic states and cerebral oxygenation during shoulder surgery in the beach chair position: a prospective, single-blind study

BACKGROUND: Administration of arginine vasopressin (AVP) is associated with reducing jugular venous (SjvO(2)) and regional cerebral (rScO(2)) oxygen saturation under propofol-remifentanil (P/R) anaesthesia. We determined whether background anaesthetics modulate the effect of AVP on cerebral oxygenation and haemodynamics. METHODS: We randomly allocated 60 adult patients scheduled for shoulder surgery in the beach chair position (BCP) into 4 groups, to receive either an intravenous bolus of saline (groups PR-S and SN-S) or 0.05 U/kg AVP (groups PR-AVP and SN-AVP) under P/R or sevoflurane-nitrous oxide (S/N) anaesthesia (n = 15 each). Haemodynamic variables, SjvO(2) and rScO(2) were measured. RESULTS: AVP significantly increased mean arterial blood pressure (MAP) and decreased rScO(2) in either anaesthetic group. AVP also decreased SjvO(2) in the P/R groups but not in the S/N groups. The AVP-treated groups showed higher MAP and cerebral desaturation (>20% rScO(2) decrease from baseline), along with lower HR and rScO(2) in the BCP than those in the saline-treated groups. In contrast, AVP did not affect SjvO(2) values or the incidence of SjvO(2) < 50%. Baseline SjvO(2) was lower and the magnitude of its reduction in the BCP was greater in the PR-AVP group than in the SN-AVP group, and the lowest SjvO(2) values were 37 ± 6 and 57 ± 8%, respectively (P < 0.001). CONCLUSIONS: The choice of anaesthetic regimen did not affect cerebral oxygenation or haemodynamics of AVP in the BCP. However, the negative effect of AVP on cerebral oxygenation should be considered, especially under P/R anaesthesia. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01687894, registered on September 18, 2012.