Factors affecting duration of stay in the intensive care unit after coronary artery bypass surgery and its impact on in-hospital mortality: a retrospective study

Abstract

Background Different risk factors affect the intensive care unit (ICU) stay after cardiac surgery. This study aimed to evaluate these risk factors. Patients and methods A retrospective analysis was conducted on clinical, operative, and outcome data from 1070 patients (mean age: 59 ± 9.8 years) who underwent isolated coronary bypass grafting CABG surgery with cardiopulmonary bypass. The outcome variable was prolonged length of stay LOS in the CICU stay (> 3 nights after CABG). Results Univariate predictors of prolonged ICU stays included a left atrial diameter of > 4 cm (P < 0.001),chronic obstructive airway disease COPD (P = 0.005), hypertension (P = 0.006), diabetes mellitus (P = 0.009), having coronary stents (P = 0.006), B-blockers use before surgery (either because the surgery was done on urgent or emergency basis or the patients have contraindication to B-blockers use) (P = 0.005), receiving blood transfusion during surgery (P = 0.001), post-operative acute kidney injury (AKI) (P < 0.001), prolonged inotropic support of > 12 h (P < 0.001), and ventilation support of > 12 h (P < 0.001), post-operative sepsis or pneumonia (P < 0.001), post-operative stroke/TIA (P = 0.001), sternal wound infection (P = 0.002), and postoperative atrial fibrillation POAF (P < 0.001). Multivariate regression revealed that patients with anleft atrial LA diameter of > 4 cm (AOR 2.531, P = 0.003), patients who did not take B-blockers before surgery (AOR 1.1 P = 0.011), patients on ventilation support > 12 h (AOR 3.931, P = < 0.001), patients who developed pneumonia (AOR 20.363, P = < 0.001), and patients who developed post-operative atrial fibrillation (AOR 30.683, P = < 0.001) were more likely to stay in the ICU for > 3 nights after CABG. Conclusion Our results showed that LA diameter > 4 cm, patients who did not take beta-blockers before surgery, on ventilation support > 12 h, developed pneumonia post-operatively, and developed POAF were more likely to have stays lasting > 3 nights. Efforts should be directed toward reducing these postoperative complications to shorten the duration of CICU stay, thereby reducing costs and improving bed availability.