Blood analyses
Venous blood samples were analysed immediately for lactate and glucose levels (Biosen C-Line, EKF Diagnostics). Thereafter, the remainder of the sample was centrifuged (Heraeus Megafuge 8, Thermo Scientific) for 10 min at 3,000 rpm with ~ 3 ml of plasma extracted into individual 1 ml microcentrifuge tubes and frozen immediately (− 80 °C) for later analysis of metanephrine, normetanephrine and catecholamine (adrenaline and noradrenaline) concentrations using commercially available enzyme linked absorbent assays (ELISA, Eagle Biosciences Inc, Nashua, New Hampshire, USA). The lower limit of detection for the adrenaline and noradrenaline assay was 5 pg ml