The overall prevalence and main determinants of prolonged mechanical ventilation in patients undergoing coronary artery bypass grafting: A systematic review

Background: Although respiratory support is necessary to maintain hemodynamic stability in patients undergoing major surgeries, prolonging the time of mechanical ventilation is considered a major complication following these procedures. The identification of potential factors related to this phenomenon should be identified. In the present systematic review, we first assess the pooled prevalence of prolonged mechanical ventilation (PMV) in patients undergoing coronary artery bypass grafting (CABG) surgery and also determine the main predictors for PMV by deeply reviewing the literature.Materials and Methods: The manuscript databases including Medline, Web of Knowledge, Google Scholar, Scopus, and Cochrane were deeply searched by the two blinded investigators for all eligible studies based on the relevant keywords. Based on the titles and abstracts, 88 records were initially included and of those, 15 articles were eligible for the final analysis.Results: The pooled prevalence of PMV in the studies that defined PMV as ventilation >24 h was 6.5% (95% confidence interval [CI]: 4.1%–10.2%) and in the studies, PMV as ventilation >48 h was 2.8% (95% CI: 1.7%–4.7%). Demographics (gender and advanced age), obesity, underlying comorbidities (hypertension, chronic kidney disease, cerebrovascular accident, high New York Heart Association class, history of chronic obstructive pulmonary disease, and history of acute coronary syndrome), emergency surgery, intraoperative characteristics (needing intra-aortic balloon pump, increased peak airway pressure, using cardiopulmonary bypass, the type of dose of anesthetics, cross-clamp time, increased units of blood transfusion, occurring cardiac ischemic events within an operation, fluid imbalance, and some anastomoses), and some postoperative outcome such as lowering O2 saturation, sequential organ failure assessment score, inotrope use, pleural effusion, delirium, and prolonged intensive care unit stay were found to be the main determinants for PMV.Conclusion: Depending on the definition of PMV, the prevalence of PMV varied from 1.7% to 10.2%. Various factors before, during, and after surgery are the predictors of PMV in these patients, which can be used to design new scoring systems to predict it.