Time-course of free radical activity during coronary artery operations with cardiopulmonary bypass

• Published in: The Journal of thoracic and cardiovascular surgery Vol. 105; no. 6; pp. 979 - 987
• Main Authors: Davies, Simon W., Duffy, John P., Wickens, David G., Underwood, Susan M., Hill, Andrew, Frederick Alladine, M., Feneck, Robert O., Dormandy, Thomas L., Walesby, Robin K.
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA Elsevier Inc 01.06.1993; AATS/WTSA; Elsevier
• Subjects: Adult; Aged; Biological and medical sciences; Cardiopulmonary Bypass - instrumentation; Coronary Artery Bypass; Female; Free Radicals - adverse effects; Free Radicals - metabolism; Humans; Lipid Metabolism; Lipid Peroxides - blood; Male; Medical sciences; Middle Aged; Oxygen - adverse effects; Oxygen - metabolism; Oxygenators - adverse effects; Oxygenators, Membrane - adverse effects; Phospholipids - blood; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the heart; Thiobarbituric Acid Reactive Substances - analysis; Human; Oxygen; Membrane oxygenator; Coronary artery; Cardiovascular disease; Exploration; Lipids; Respiratory intensive care; Bubble oxygenator; Free radical; Cardiopulmonary bypass; Surgery; Complication; Comparative study; Peroxidation
• ISSN: 0022-5223; 1097-685X
• DOI: 10.1016/S0022-5223(19)33769-9

Myocardial and pulmonary impairment after cardiopulmonary bypass may be caused by oxygen free radicals produced by reperfusion and by activated neutrophils. Free radical activity was assessed by assays for lipid peroxidation (thiobarbituric acid-reactive material) and phospholipid-esterified diene conjugation (18:2[9,11]/18:2[9,12] molar ratio) in 25 patients during coronary artery operations. Arterial blood samples were obtained before, during the ischemic period, and for 24 hours thereafter. There were no significant changes in free radical indices during the ischemic periods, but after cessation of bypass they increased significantly. Ten minutes after bypass thiobarbituric acid-reactive material rose from 96 (median; range 65 to 145) nmol/gm albumin to 138 (85 to 200) nmol/gm albumin (p < 0.001), and molar ratio rose from 2.23 % (0.45% to 7.70%) to 2.51 % (0.39% to 7.93%) (p < 0.02). Values of thiobarbituric acid-reactive material subsequently decreased, but molar ratio reached a peak at 4 hours after bypass, 2.64% (0.55% to 10.08%) (p < 0.001), thereafter returning to baseline. The postoperative increases in thiobarbituric acid-reactive material and in molar ratio were correlated (r = +0.53; p = 0.006). These increases in thiobarbituric acid-reactive material and in molar ratio were not related to age, preoperative left ventricular function, or the number of grafts performed. Increase in thiobarbituric acid-reactive material correlated with the duration of cardiopulmonary bypass (r = +0.43; p = 0.03). In 10 patients in whom cardiopulmonary bypass was performed using a bubble oxygenator, the increases in thiobarbituric acid-reactive material were significantly greater than in the 15 in whom a membrane oxygenator was used (p < 0.02). These data show that after apparently uncomplicated coronary operations with bypass there is an increase in lipid peroxidation and diene conjugation, indicating increased free radical activity. This increase varies between patients and does not relate to patient or surgical factors but may depend on the type of oxygenator employed during bypass. (J Thorac Cardiovasc Surg 1993;105:979-87)