Predictors, Frequency, and Clinical Impact of Prolonged Mechanical Ventilation in Adult Cardiac Surgery Patients at a Tertiary Cardiac Center in Pakistan

Abstract

Objectives: This study aimed to determine the frequency, causes, and associated factors of prolonged mechanical ventilation (PMV) in adult patients undergoing cardiac surgery at a tertiary cardiac care center. Methodology: A prospective observational study was conducted at the Pervaiz Elahi Institute of Cardiology, Bahawalpur, Pakistan, from January 2024 to August 2025. Adult surgical candidates aged 18–65 years undergoing elective or urgent cardiac procedures were enrolled consecutively. PMV was defined as invasive mechanical ventilation lasting ≥24 hours postoperatively. Demographic characteristics, comorbidities, intraoperative parameters, and postoperative complications were recorded. Statistical analyses included univariate and multivariate logistic regression to identify independent predictors of PMV, with significance set at p<0.05. Results: Among 89 patients, 16 (18.0%) required PMV. COPD (37.5% vs 13.7%; p=0.025) and reduced LVEF <40% (50.0% vs 23.1%; p=0.029) were significantly more common among PMV patients. PMV was associated with longer cardiopulmonary bypass (median 136.7 vs 112.1 minutes; p=0.002) and aortic cross-clamp times (median 98.2 vs 80.8 minutes; p=0.004). Postoperative pulmonary complications (50.0% vs 9.6%; p<0.001) and AKI (31.2% vs 12.3%; p=0.060) were also more prevalent. PMV patients had significantly greater ICU stay (7.0 vs 3.5 days; p<0.001), hospital stay (12 vs 8 days; p<0.001), and in-hospital mortality (18.8% vs 4.1%; p=0.034). Independent predictors included COPD (aOR=4.0; p=0.037), LVEF <40% (aOR=2.8; p=0.048), and longer CPB and cross-clamp durations. Conclusion: PMV is a frequent and clinically significant postoperative complication in adult cardiac surgery patients. Preoperative pulmonary disease, reduced ventricular function, prolonged CPB, and cross-clamp durations significantly increase the risk. Recognizing these modifiable and non-modifiable factors can guide perioperative optimization strategies to reduce ICU burden, improve clinical outcomes, and minimize mortality.