Cardiopulmonary Bypass Increases Endogenous Carbon Monoxide Production

• Published in: Journal of cardiothoracic and vascular anesthesia Vol. 23; no. 6; pp. 802 - 806
• Main Authors: Schober, Patrick, MD, Kalmanowicz, Melanie, MD, Schwarte, Lothar A., MD, PhD, Loer, Stephan A., MD, PhD, MSc
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.12.2009
• Subjects: Aged; Anesthesia & Perioperative Care; Anesthesia, General - methods; carbon monoxide; Carbon Monoxide - metabolism; Carboxyhemoglobin - metabolism; cardiopulmonary bypass; Cardiopulmonary Bypass - adverse effects; Critical Care; Female; Humans; Male; Oxidative Stress; oxygenator; Prospective Studies; Tidal Volume; Treatment Outcome; carbon monoxide; cardiopulmonary bypass; oxygenator
• ISSN: 1053-0770; 1532-8422
• DOI: 10.1053/j.jvca.2009.03.001

Objective Endogenous carbon monoxide (CO) production results from heme metabolism catalyzed by heme oxygenase (HO) enzymes of which HO-1 is inducible by oxidative stress. Cardiopulmonary bypass provokes oxidative stress associated with systemic and pulmonary inflammatory responses. Therefore, the authors hypothesized that cardiopulmonary bypass is associated with an increase in endogenous carbon monoxide production. Design A prospective, observational study. Setting A cardiothoracic operating room. Participants Forty patients undergoing cardiac surgery with cardiopulmonary bypass. Interventions None. Measurements and Main Results End-tidal CO levels and arterial carboxyhemoglobin concentrations were measured before and after cardiopulmonary bypass. End-tidal CO concentrations and carboxyhemoglobin levels were increased significantly after cardiopulmonary bypass as compared with prebypass values (median [interquartile range]: end-tidal CO levels: 33 [20-42] ppm v 22 [16-32] ppm, p < 0.01; carboxyhemoglobin 1.3% [1.0%-1.3%] v 0.9% [0.6%-1.0%], p < 0.01). To exclude that the observed increases were caused by CO accumulation during CPB, the authors also assessed carboxyhemoglobin concentrations in the arterial and venous limb of the oxygenator, indicating that CO is eliminated across the membrane oxygenator during CPB. Conclusions Cardiac surgery with cardiopulmonary bypass is associated with an increase in endogenous CO production.