Optimal perfusion during extra-corporeal circulation.

A multivariate analysis of 130 consecutive patients operated during one month in our hospital was carried out to determine the influence of age and blood flow during cardiopulmonary bypass on the renal response to cardiac surgery. The postoperative level of serum creatinine could be related to three variables: preoperative serum creatinine, age and lowest blood flow during cardiopulmonary bypass. A higher blood flow is needed during cardiopulmonary bypass in older patients and in patients with a raised pre-operative serum creatinine to prevent deterioration in renal function postoperatively. A nomogram is given for the lowest blood flow during CPB, corrected for age and the pre-operative serum creatinine level, which will result in a desired postoperative serum creatinine of 110 mumol/l.