Brit. J. Anaesth. (1965), 37, 738 MODERATE HYPOTHERMIA EN MAN: HAEMODYNAMIC AND METABOLIC EFFECTS

Studies were performed on four patients undergoing intracranial operation during the induction and reversal of surface hypothermia to 30 °C. Oxygen uptake decreased an average of 26 per cent from 34° to 30°C to a mean value of 48 per cent of predicted basal uptake. At the same time, cardiac output decreased only 11.5 per cent, resulting in a consistent rise in calculated mixed venous oxygen saturation from a mean of 76 to 81 per cent at 30°C. As a result of this and the effect of cooling on oxygen dissociation, the estimated tension of oxygen in mixed venous blood remained virtually unchanged. When shivering was allowed to occur in two patients, oxygen uptake increased approximately 50 per cent without any concomitant increase in cardiac output. Observed right atrial and SVC oxygen saturations correlated well with calculated mixed venous oxygen saturations with regard to direction and magnitude of change with change in temperature.