APACHE II score predicts mortality in patients requiring prolonged ventilation in a weaning center

Abstract

Background: Little is known about the diagnostic accuracy of the APACHE II scoring system in prolonged mechanical ventilation. The aim of this study was to assess the utility of APACHE II in order to predict in-hospital mortality, length of stay (LOS) and discharge destination of patients in a weaning centre. Methods: The study group included 130 consecutive patients (median age 71 years; IQR 62-77). APACHE II was assessed based on the worst values taken during the first 24 hours post admission. The primary outcome was in-hospital mortality. LOS and discharge destination were considered secondary outcomes. Results: The APACHE II median score was 11 points (IQR 9-14) while 15 patients (11.5%) died. Mortality was lower in men (10.3%) than in women (14%) (P = 0.04). APACHE II was higher in non-survivors (15; IQR 10.25-19.5) compared to survivors (11; 8.25-14) (P < 0.001). In a bivariate analysis, APACHE II predicted mortality with good diagnostic accuracy (AUROC = 0.714; P = 0.007). In a multivariate analysis APACHE II (OR = 1.22; 95% CI: 1.06-1.40 per 1 point) and mode of ventilation (OR = 0.28; 95% CI: 0.08-0.99; CPAP vs. BIPAP) only predicted mortality. The median length of stay (LOS) was 28 days (IQR 20-39). There was weak correlation between APACHE II and LOS (R = 0.23; P = 0.01). Most patients were transferred to a rehabilitation center (53.9%) or a geriatric ward (13.9%). APACHE II did not differ between patients discharged to different healthcare facilities (P = 0.14). Conclusion: The APACHE II score is a powerful tool for predicting mortality of patients undergoing weaning from prolonged mechanical ventilation.