Effect of cardiopulmonary bypass on pulmonary gas exchange: a prospective randomized study.
BACKGROUND
Conventional coronary artery bypass surgery is associated with postoperative pulmonary dysfunction. Inflammation due to cardiopulmonary bypass has been regarded as one of the main causes. In this study, we investigated the effect of coronary revascularization with or without cardiopulmonary bypass on pulmonary function.


METHODS
Fifty-two patients (40 male, mean age 60.1 years) were prospectively randomized to undergo coronary revascularization via median sternotomy, with or without normothermic cardiopulmonary bypass. Alveolar-arterial oxygen gradients were measured before and after induction of anesthesia, postoperatively in the intensive care unit during mechanical ventilation and 6 hours after tracheal extubation. The techniques of anesthesia and mechanical ventilation were standardized throughout.


RESULTS
Patient characteristics were similar in the two groups. The alveolar-arterial oxygen gradients increased progressively throughout the perioperative period, with no significant differences in the two groups at any time during the study.


CONCLUSIONS
Myocardial revascularization with or without cardiopulmonary bypass caused a similar degree of pulmonary dysfunction, as assessed by alveolar-arterial oxygen gradient. Our study suggests that the deterioration in pulmonary gas exchange associated with cardiac surgery is due to factors other than the use of cardiopulmonary bypass.
Cox
C M
CM
Department of Anaesthesia and Bristol Heart Institute, University of Bristol, United Kingdom.
Ascione
R
R
Cohen
A M
AM
Davies
I M
IM
Ryder
I G
IG
Angelini
G D
GD
D001831:Body Temperature; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000379:methods; D016009:Chi-Square Distribution; D001026:Coronary Artery Bypass / Q000009:adverse effects; D003422:Critical Care; D005260:Female; D005500:Follow-Up Studies; D006324:Heart Arrest, Induced / Q000379:methods; D006801:Humans; D007442:Intubation, Intratracheal; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D011175:Positive-Pressure Respiration; D011183:Postoperative Complications; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000378:metabolism; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012120:Respiration Disorders / Q000209:etiology
D010100:Oxygen