Risk factors for prolonged mechanical ventilation (PMV) post-coronary bypass surgery

Postoperative intensive care plays a crucial role in the perioperative management of coronary artery bypass graft (CABG) surgery. It is well established that patients requiring prolonged mechanical ventilation (PMV) have an increased risk of developing multiple secondary complications such as ventilator-associated pneumonia accounting for the increase of overall morbidity and mortality. The primary focus of our investigation was to identify new risk factors associated with PMV following CABG surgery.

All patients who underwent isolated coronary artery bypass surgery and were treated in an interdisciplinary surgical intensive care unit (ISICU) of a tertiary University Medical Center in 2023 were included in this retrospective observational study.

A total of 339 patients were included in the study. Among the 280 patients who were successfully extubated within 24 hours after surgery (82.6%), the median ventilation time was 15 hours. In contrast, in the PMV group, the median ventilation time was 48.5 hours. Explorative statistical analysis showed significant differences between the two groups for duration of ventilation, ischemia time, time on cardiopulmonary bypass (CPB), duration of surgery, intensive care unit (ICU) length of stay, hospital length of stay, postoperative drainage loss within 12 and 24 hours after surgery, as well as the European System for Cardiac Operative Risk Evaluation (EuroSCORE). In-hospital mortality was greater in patients with PMV compared to patients without PMV (10.2% vs. 0.0%, P<0.001). Multivariate logistic regression analysis revealed longer time on CPB [odds ratio (OR) =1.01, 95% confidence interval (CI): 1-1.02], a lactate peak within the first 24 hours (OR =1.35, 95% CI: 1.2-1.53), and a higher preoperative EuroSCORE (OR =1.23, 95% CI: 1.05-1.45) as significant independent association for the development of PMV.

Comprehensive understanding of the factors that increase the risk of PMV and a precise characterization of patients prone to PMV are considered essential for the management by the attending intensivist. Early identification of risk factors enables the implementation of targeted interventions, which may optimize intensive care management and ultimately contribute to improved patient outcomes.