Systemic haemodynamics and oxygenation during haemodilution in children

Cardiac index increased from 3·1 (SD 0·5) L min-1 m-2 at baseline to 4·4 (0·5) L min-1 m-2 at the end of surgery, when packed cell volume was 16 (1)%; this change, compensating for the decline in oxygen carrying capacity, was associated with a fall in systemic vascular resistance and a rise in stroke volume. Oxygen extraction from haemoglobin rose from 0·22 (0·05) to 0·33 (0·06). Perioperative blood loss was 40% of circulating blood volume; however, owing to reinfusion of autologous blood (and use of a cell saver in three patients), the haemoglobin one day after operation was only 19% lower than preoperatively (9·9 [1·5] vs 12·5 [2·5] g/dL). In this study, children seemed at least as able as adults to compensate for the effects of haemodilution, which allowed major surgery without transfusion of homologous blood.