Hemodynamic patterns of survivors and nonsurvivors during high risk elective surgical operations

Postoperative survivors' and nonsurvivors' hemodynamic and oxygen transport patterns have been extensively studied, and the early postoperative circul atory events leading to organ failures and death have been documented. Outc ome was improved when potentially lethal circulatory patterns were treated during the early (thr first 8-12 hours) postoperative period; but after the appearance of organ failure, reversal of nonsurvival patterns did not impr ove the outcome. The purpose of this study was to describe prospectively in traoperative circulatory deficiencies that precede shock organ failures, an d death. The ultimate aim was to elucidate nonsurvivor patterns at the earl iest possible time to develop more effective preventive strategies for leth al organ failures. This approach is based an the assumption that it is easi er and more effective to prevent the initiators of shock such as hypovolemi a, hypoxemia, poor tissue perfusion, and tissue hypoxia, than to treat the mediators of organ failure, such as cytokines, antigens, eicosinoids, and h eat shuck proteins. We monitored 356 high risk elective surgical patients w ith preoperative and intraoperative hemodynamic monitoring by the pulmonary artery (PA) thermodilution catheter, The conventionally monitored mean art erial pressure and heart rate remained in the normal range in both groups; the nonsurvivor pattern included decreased cardiac index, stroke index, str oke work, oxygen delivery, and oxygen consumption. I,ow oxygen consumption was partly compensated by increased oxygen extraction rates, and arterial p ressures were maintained by Increasing systemic vascular resistance. The ea rly temporal pattern of nonsurvivors' changes were similar to those describ ed during the postoperative period that preceded development of organ failu re and death. This suggests that lethal circulatory dysfunctions may begin during the intraoperative period but become more apparent before and after organs fail during later postoperative stages.