Factors causing prolonged mechanical ventilation and peri-operative morbidity after robot-assisted coronary artery bypass graft surgery

Robot-assisted coronary artery bypass graft [robot-assisted (coronary artery bypass grafting (CABG)] surgery is the latest treatment for coronary artery disease. However, the surgery extensively affects cardiac and pulmonary function, and the risk factors associated with peri-operative morbidity, including prolong mechanical ventilation (PMV), have not been fully examined. In this retrospective cohort study, a total of 382 patients who underwent robot-assisted internal mammary artery harvesting with mini-thoracotomy direct-vision bypass grafting surgery (MIDCABG) from 2005 to 2012 at our tertiary care hospital were included. The definition of PMV was failure to wean from mechanical ventilation more than 48h after the surgery. Risk factors for PMV, and peri-operative morbidity and mortality were analyzed with a multivariate logistic regression model. Forty-three patients (11.3%) developed PMV after the surgery, and the peri-operative morbidity and mortality rates were 38 and 2.6%, respectively. The risk factors for PMV were age, left ventricular ejection fraction (LVEF), the duration of one-lung ventilation for MIDCABG (beating time), and peak airway pressure at the end of the surgery. Furthermore, age and anesthesia time were found to be independent risk factors for peri-operative morbidity, whereas age, LVEF, and anesthesia time were the risk factors for peri-operative mortality. These findings may help physicians to properly choose patients for this procedure, and provide more attention to patients with higher risk after surgery to achieve better clinical outcomes.