Pulmonary abnormalities and complications after coronary surgery have been attributed to cardiopulmonary bypass.
We examined Cs, ABGs, spirometry, and pulmonary complications (death, pneumonia, pleural effusions, and time to extubation) before and after coronary surgery in a prospective trial of 200 patients randomized to OPCAB versus CABG/CPB. Cs, ABGs, and hemodynamics were measured in the OR preop and postop. Spirometry was obtained preop and 4–6 weeks postop. Chest radiographs (CXR) were taken preop, and on postop days 0, 1 and 3.
There were no group differences in preop age, COPD, smoking, NYHA class, spirometry, ABGs, Cs, hemodynamics, or CXRs. Postop Cswas reduced more in the OPCAB group than the CABG/CPB group (−15.1±10.4ml/cmH2O vs -11.5±10.6ml/cmH2O, p=0.017), dominantly associated with rotatation of the heart into the right chest to perform bypass to posterior vessels (p=.0004). The OPCAB group also received more total intraop fluids (4479±1346ml vs 3611±1072ml, p<.0001), had higher postop pulmonary arterial diastolic (14.9±5.6mmHg vs 11.9±5.2mmHg, p<.0001) and central venous pressures (10.4±4.6mmHg vs 8.4±4.7, p<.0001), and more findings suggestive of pulmonary edema on day 1 CXR (p=0.04). Despite lower Cs and more pulmonary edema, the OPCAB patients had higher postop PaO2 on FiO2 1.0 (273±98 torr vs 224±94 torr, p=.001) and were extubated earlier than the CABG/CPB patients (p=.001). There were no differences in postop spirometry or in the rates of death, pneumonia, pleural effusion, and respiratory failure.CONCLUSIONS: Compared to CABG/CPB, OPCAB is associated with a greater reduction in postop Cssecondary to rotatation of the heart into the right chest and more fluids. OPCAB is associated with improved gas exchange, earlier extubation, and no difference in spirometry or rates of death, pneumonia, and pleural effusion compared to CABG/CPB.
Efforts to reduce the need for rotation of the heart into the right chest and reduction in fluids during OPCAB may reduce the Cs changes seen in OPCAB. OPCAB may improve pulmonary outcomes and reduce costs by expediting extubation.
G.W. Staton, Medtronic, Grant monies.