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Oxygen free radical generation during cardiopulmonary bypass: correlation with complement activation.
Circulation
|November 1, 1986
Summary
Cardiopulmonary bypass activates complement, increasing oxygen free radicals and white blood cell buildup in the lungs. This suggests a role for complement activation and free radicals in the complications of extracorporeal circulation.
Area of Science:
- Biomedical Engineering
- Immunology
- Cardiovascular Surgery
Background:
- Cardiopulmonary bypass (CPB) is associated with systemic inflammatory responses.
- The interplay between complement activation, leukocyte sequestration, and oxidative stress during CPB requires further elucidation.
Purpose of the Study:
- To investigate the relationships among complement activation, pulmonary leukosequestration, and oxygen free radical generation during CPB.
- To differentiate the effects of CPB and protamine administration on these parameters.
Main Methods:
- Prospective study of 15 patients undergoing myocardial revascularization with CPB.
- Measurement of plasma C3a, C4a, and hydrogen peroxide (H2O2) levels pre-, during, and post-CPB.
- Monitoring of pulmonary polymorphonuclear leukocyte sequestration.
Main Results:
- CPB activated the alternate complement pathway (indicated by C3a increase).
- This activation correlated with increased plasma H2O2 and pulmonary leukosequestration.
- Protamine administration activated the classical complement pathway (indicated by C4a increase) but did not alter H2O2 levels.
Conclusions:
- CPB-induced complement activation is linked to increased oxygen free radical generation and pulmonary leukosequestration.
- Both complement activation and oxidative stress may contribute to the pathophysiology of CPB.
- Protamine's effect on complement is distinct from CPB's impact on oxidative stress.