Prolonged mechanical ventilation after CABG: risk factor analysis

Objective: Prolonged ventilation (PV) after coronary artery bypass graft (CABG) surgery is a common postoperative complication. Preoperative and operative parameters were evaluated in order to identify the patients at risk for prolonged ventilation postoperatively in coronary artery bypass graft (CABG) patients.

Design: Retrospective.

Setting: Research and training hospital, single institution.

Participants: The authors analyzed the prospectively collected data of 830 on- and off-pump coronary bypass patients.

Interventions: The relationships of PV (>24 hours) with preoperative and operative parameters were evaluated with logistic regression analysis.

Measurements and main results: Forty-six patients (5.6%) required PV postoperatively. Hospital mortality was significantly higher in this group (45.7% v 4.0%; p = 0.0001). Univariate analysis showed that these patients were older (65.6±9.3 v 60.4±9.9; p = 0.001), had higher incidences of cerebrovascular disease (21.7% v 10.5%; p = 0.032), advanced ASA (58.7% v 41.8%; p = 0.026) and NYHA classes (32.6% v 12.2%; p = 0.001), and chronic renal dysfunction (20.0% v 4.0%; p = 0.0001). Concomitant procedures were more commonly performed in these patients (30.4% v 7.8%; p = 0.0001), and total durations of perfusion were longer (147.2±69.1 v 95.7±33.9 minutes; p = 0.0001). In regression analysis, advanced NYHA class (odds ratio = 8.2; 95% CI = 1.5-43.5; p = 0.015), chronic renal dysfunction (odds ratio = 7.7; 95% CI = 1.3-47.6; p = 0.027), and longer perfusion durations (p = 0.012) were found to be independently associated with delayed weaning from the ventilator. Every 1-minute increase over 82.5 minutes of cardiopulmonary bypass increased risk of delayed extubation by 3.5% (95% CI = 0.8%-6.4%).

Conclusions: Postoperative prolonged ventilation is associated with advanced NYHA class, chronic renal dysfunction and longer perfusion times in CABG patients.