Objective: To compare pulmonary function, functional capacity, and clinical outcomes among conventional mechanical ventilation (CMV), early open-lung (EOL), and late open-lung (LOL) strategies after off-pump coronary artery bypass surgery (OPCAB).
Design: Prospective, randomized, and double-blinded study.
Setting: Two hospitals of the Federal University of Sao Paulo, Brazil.
Participants: Ninety-three patients undergoing elective first-time OPCAB.
Interventions: Patients were randomized into 3 groups: CMV (n=31); LOL (n=32) initiated upon intensive care unit (ICU) arrival; EOL (n = 30) initiated after intubation.
Measuraments and main results: Spirometry was performed at bedside preoperatively and on postoperative days (PODs) 1, 3, and 5. Partial pressure of arterial oxygen (PaO2) and pulmonary shunt fraction were evaluated presurgically and on POD 1; 6-minute walk test (6MWT) was performed presurgically and on POD 5. Both open-lung groups demonstrated higher forced vital capacity and forced expiratory volume in 1 second on PODs 1, 3 and 5 compared to the CMV group (p<0.05). Similar results were found in relation to the 6MWT distance. Shunt fraction was lower and PaO2 was higher in both open-lung groups (p<0.05). Open-lung groups had shorter intubation time and hospital stay as well as fewer respiratory events (p<0.05). No statistical difference was found relative to the aforementioned results when the EOL and LOL groups were compared.
Conclusions: Both open-lung strategies were able to promote higher pulmonary function preservation and greater recovery of functional capacity with better clinical outcomes after OPCAB. No difference in outcome was found when comparing initiation of OLS intraoperatively or after ICU arrival.
Keywords: functional capacity; off-pump coronary artery bypass surgery; open-lung ventilation; pulmonary function.
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