Background: Heparin coating of the cardiopulmonary bypass circuit reduces the activation of the terminal part of the complement cascade. Conflicting data are reported concerning neutrophil activation and postoperative lung dysfunction. In this study, we compared three different types of oxygenator: a bubble oxygenator, a conventional hollow-fiber oxygenator, and a heparin-coated oxygenator and circuit.
Methods: Sixty patients undergoing myocardial revascularization were randomly assigned to one of three oxygenator groups. All the patients were free from preoperative lung dysfunction. Lung function was studied with repeated measurements of respiratory index, intrapulmonary shunt, alveolar dead space, ventilation/perfusion ratio, and static thoracopulmonary compliance.
Results: Immediately after cardiopulmonary bypass, the intrapulmonary shunt and respiratory index values in the bubble oxygenator and hollow-fiber oxygenator groups increased more than those in the heparin-coated oxygenator group. In the intensive care unit, the between-group difference in intrapulmonary shunt disappeared, but the within-group difference in respiratory index (from baseline) remained for the bubble oxygenator group. The other three variables did not significantly differ between groups. Intubation time and stay in the intensive care unit did not differ between groups.
Conclusions: Heparin-coated circuits exert a protective effect on pulmonary function. However, their use did not modify the postoperative clinical course of patients with normal lung function preoperatively.