title: Cardiopulmonary bypass increases endogenous carbon monoxide production.
abstract: 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.
  
  
  METHODS
  A prospective, observational study.
  
  
  METHODS
  A cardiothoracic operating room.
  
  
  METHODS
  Forty patients undergoing cardiac surgery with cardiopulmonary bypass.
  
  
  METHODS
  None.
  
  
  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.
authors.affiliation: Department of Anesthesiology, VU University Medical Center, Amsterdam, The Netherlands. P.Schober@vumc.nl
authors.forename: Patrick
authors.initials: P
authors.lastname: Schober
authors.forename: Melanie
authors.initials: M
authors.lastname: Kalmanowicz
authors.forename: Lothar A
authors.initials: LA
authors.lastname: Schwarte
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Loer
mesh_terms: D000368:Aged; D000768:Anesthesia, General / Q000379:methods; D002248:Carbon Monoxide / Q000378:metabolism*; D002263:Carboxyhemoglobin / Q000378:metabolism; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D018384:Oxidative Stress; D011446:Prospective Studies; D013990:Tidal Volume; D016896:Treatment Outcome
chemical_list: D002248:Carbon Monoxide; D002263:Carboxyhemoglobin