**The Physiology and the Clinical Significance of Postoperative Hyperlactatemia After Pediatric Cardiac Surgery**

Vered Molina-Hazan and Gideon Paret *Department of Pediatric Critical Care, Safra Children's Hospital, Chaim Sheba Medical Center, Tel Hashomer, Affiliated to The Sackler School of Medicine, Tel Aviv University, Tel Aviv Israel* 

#### **1. Introduction**

306 Perioperative Considerations in Cardiac Surgery

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Value of a Doppler-derived index combining systolic and diastolic time intervals in predicting outcome in primary pulmonary hypertension. *Am J Cardiol*. 81, 9, 1157Lactate was first described by Berzelius in 1807 when he discovered it in its modified form in meat juices. It has been used as a marker of cellular hypoxia and tissue malperfusion, and hyperlactatemia has been associated with postoperative complications and mortality. Notably, high blood lactate concentrations have been associated with increased mortality and morbidity in children after cardiac operations (Siegel et al., 1996). Hyperlactatemia associated with metabolic acidosis is a major predictor of mortality of patients with sepsis or after cardiovascular shock, and the evolution of lactate concentration after therapeutic management can more accurately predict the outcome (Bakker et al., 1996; Weil & Afifi, 1970). Blood lactate concentrations are more easily obtained and measured than other monitoring variables, even before any invasive monitoring, such as mean arterial blood pressure, is available. This use of lactate as a clinical endpoint is based on a substantial body of literature, including multiple prospective studies on trauma, surgery or sepsis, patients and in mixed populations of critically ill patients.
