MIXED VENOUS OXYGEN-SATURATION MONITORING DURING LIVER-TRANSPLANTATION

High mixed venous oxygen saturation (SVO2BAR) values due to limited ox ygen extraction capacities are reported in some patients with severe l iver disease. The aim of this study was to evaluate the usefulness of SVO2BAR monitoring to assess adequate oxygen supply in such patients s cheduled for liver transplantation. Nineteen patients with oxygen extr action ratio below 12% were analysed and compared to 20 patients with a pre-operative ratio over 17%. The two groups were comparable with re gard to initial pathology, preload and haemoglobin levels. SVO2BAR val ues measured discontinuously by co-oximetry were unaffected by the fir st part of surgery and the clamping period in patients with low oxygen extraction ratio. In these patients, SVO2BAR was never correlated to oxygen supply during the whole procedure whereas good correlation was noted before and after unclamping in the other group. Tissue hypoxia d etected by a dependent oxygen consumption-oxygen supply relationship o ccurred at clamping and unclamping in patients with initial low oxygen extraction capacities. It is concluded that expensive SVO2BAR continu ous monitoring may not be effective in reflecting changes in oxygen su pply in anaesthetized patients with initial severely impaired oxygen e xtraction capacity.