Anaerobic Metabolism During Cardiopulmonary Bypass: Predictive Value of Carbon Dioxide Derived Parameters

• Published in: The Annals of thoracic surgery Vol. 81; no. 6; pp. 2189 - 2195
• Main Authors: Ranucci, Marco, Isgrò, Giuseppe, Romitti, Federica, Mele, Sara, Biagioli, Bonizella, Giomarelli, Pierpaolo
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.06.2006; Elsevier Science
• Subjects: Aged; Anaerobiosis; Area Under Curve; Biological and medical sciences; Carbon Dioxide - blood; Cardiopulmonary Bypass - adverse effects; Coronary Artery Bypass; Female; Heart Valve Diseases - surgery; Humans; Lactates - blood; Male; Medical sciences; Middle Aged; Monitoring, Intraoperative; Oxygen - blood; Oxygen Consumption; Partial Pressure; Predictive Value of Tests; Prospective Studies; ROC Curve; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the respiratory system; 17; Cardiopulmonary bypass; Treatment; Respiratory disease; Surgery; Carbon dioxide; Predictive value; Parameter; Thorax; Metabolism
• ISSN: 0003-4975; 1552-6259
• DOI: 10.1016/j.athoracsur.2006.01.025

Hyperlactatemia during cardiopulmonary bypass (CPB) is a common event and is associated to a high morbidity and mortality after cardiac operations. The present study is aimed to identify the possible predictors of hyperlactatemia during CPB among a series of oxygen and carbon dioxide derived parameters measured during CPB. This is a prospective observational study on 54 patients undergoing cardiac surgery with CPB. Hyperlactatemia was defined as an arterial lactate concentration higher than 3 mMol/L. Serial blood lactate assays have been performed during CPB, and their association to a number of oxygen and carbon dioxide derived parameters was explored. Arterial blood lactate concentration was positively correlated to the CPB duration, the carbon dioxide elimination, and the respiratory quotient, and negatively correlated to the presence of the aortic cross-clamping, the body surface area, the ratio between the oxygen delivery and the carbon dioxide production, and the arterial oxygen saturation. Predictors of hyperlactatemia during CPB are a carbon dioxide production higher than 60 mL · min -1· m -2, a respiratory quotient higher than 0.9, and a ratio between oxygen delivery and carbon dioxide production lower than 5. Carbon dioxide derived parameters are representative of hyperlactatemia during CPB, as a result of the carbon dioxide produced under anaerobic conditions through the buffering of protons by the bicarbonate system. The carbon dioxide elimination rate measured at the exhaled site of the oxygenator may be used for an indirect assessment of the metabolic state of the patient.