Does On-Pump Normothermic Beating-Heart Valve Surgery with Low Tidal Volume Ventilation Protect the Lungs?

Background: Postoperative pulmonary dysfunction following cardiopulmonary bypass (CPB) usually develops secondary to the inflammatory process with contact activation, hypothermia, operative trauma, general anesthesia, atelectasis, pain, and pulmonary ischemia/reperfusion due to crossclamping. The aim of the present study was to evaluate the effects of an on-pump, normothermic, and beating-heart technique and of low-volume ventilation on lung injury.Methods: We compared the results for 20 patients who underwent operations with an on-pump, normothermic, and beating-heart technique of mitral valve surgery with low-volume ventilation (group 1) with the results for 23 patients who underwent their operations with an on-pump, hypothermic cardiacarrest technique (group 2). In both groups, blood samples were collected from the right superior pulmonary vein, and inflammation and oxidative stress markers (malondialdehyde, lactic acid, platelet-activating factor, and myeloperoxidase) were studied.Results: Malondialdehyde, myeloperoxidase, and lactate values were significantly lower in group 1 than in group 2 just before the termination of CPB (P < .05). We observed no differences between the 2 groups with regard to values for platelet-activating factor.Conclusions: Inflammation and oxidative stress markers were lower in the group of patients who underwent beating-heart valve surgery with low-volume ventilation. These results reflect less of an ischemic insult and lower inflammation compared with the results for the patients who underwent conventional operations.