Pulmonary outcomes of off-pump vs on-pump coronary artery bypass surgery in a randomized trial.
OBJECTIVE
Comparison of pulmonary outcomes after off-pump coronary artery bypass (OPCAB) vs on-pump coronary artery grafting with cardiopulmonary bypass (CABG/CPB).


METHODS
We examined preoperative and postoperative respiratory compliance, fluid balance, hemodynamics, arterial blood gases, chest radiographs, spirometry, pulmonary complications, and time to extubation in a prospective trial of 200 patients randomized to OPCAB vs CABG/CPB performed by one surgeon.


RESULTS
One CABG/CPB patient and two OPCAB patients required mitral valve repair or replacement and were withdrawn. After three crossovers from CABG/CBP to OPCAB and one crossover from OPCAB to CABG, 97 CABG/CPB patients and 100 OPCAB patients remained. There were no significant preoperative demographic differences between groups. Postoperative compliance was reduced more after OPCAB than after CABG/CPB (- 15.4 +/- 10.7 mL/cm H(2)O vs - 11.2 +/- 10.1 mL/cm H(2)O [mean +/- SD]; p = 0.007), associated with rotation of the heart into the right chest to perform posterolateral bypasses (p < 0.001) and the concomitant increased fluid requirements necessary to maintain hemodynamic stability during rotation of the heart. In addition to higher intraoperative fluid intake (4,541 +/- 1,311 mL vs 3,585 +/- 1,033 mL, p < 0.0001), OPCAB patients had higher intraoperative fluid balance (3,903 +/- 1,315 mL vs 1,772 +/- 1,373 mL, p < 0.0001), and higher postoperative pulmonary arterial diastolic pressure (15.0 +/- 5.5 mm Hg vs 11.8 +/- 5.2 mm Hg, p < 0.0001) and central venous pressure (10.4 +/- 4.5 mm Hg vs 8.4 +/- 4.7 mm Hg, p < 0.0001). Despite lower compliance, immediate postoperative Pao(2) on fraction of inspired oxygen of 1.0 (275 +/- 97 torr vs 221 +/- 92 torr, p = 0.001) was higher after OPCAB and extubation was earlier (p = 0.001). Postoperative chest radiographs, spirometry, mortality, reintubation, or readmission for pulmonary complications were not different between groups.


CONCLUSIONS
Compared to CABG/CPB, OPCAB was associated with a greater reduction in postoperative respiratory compliance associated with increased fluid administration and rotation of the heart into the right chest to perform posterolateral grafts. OPCAB yielded better gas exchange and earlier extubation but no difference in chest radiographs, spirometry, or rates of death, pneumonia, pleural effusion, or pulmonary edema.
Staton
Gerald W
GW
Department of Medicine, Division of Pulmonary and Critical Care Medicine, Emory University School of Medicine, Medical Director, Wesley Woods Long Term Hospital, 1821 Clifton Rd NE, Atlanta, GA 30329, USA. gerald_staton@emoryhealthcare.org
Williams
Willis H
WH
Mahoney
Elizabeth M
EM
Hu
Jeff
J
Chu
Haitao
H
Duke
Peggy G
PG
Puskas
John D
JD
D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D047549:Coronary Artery Bypass, Off-Pump / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008170:Lung Compliance; D008171:Lung Diseases / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011659:Pulmonary Gas Exchange; D013902:Radiography, Thoracic; D013147:Spirometry; D016896:Treatment Outcome; D014882:Water-Electrolyte Balance