Outcomes of patients requiring prolonged mechanical ventilation in Singapore

Background: Patients requiring prolonged mechanical ventilation (PMV) represent an emerging challenge for the healthcare system. These patients survive the acute stage of critical illness but have persistent organ dysfunction and remain dependent on mechanical ventilator. Methods: This was a single centre cohort study of patients admitted to medical intensive care unit (ICU) between 2012 and 2015 who required mechanical ventilation for ≥ 21 days. Primary outcome was 180-day mortality. Results: A total of 128 patients who required PMV were included in the study. Median [interquartile range (IQR)] age was 66 [58–75] years old. The primary reason for ICU admission was predominantly respiratory cause (n=106, 82.8%). 180-day mortality was 64.1%. Multivariate analysis using Cox proportional hazards regression found that age, comorbidity of hyperlipidemia and day 21 thrombocytopenia (platelets ≤ 150×10 9 /L) predicted 180-day mortality, with a hazard ratio of 1.02 [1.00–1.04]; 1.60 [1.03–2.49]; and 3.72 [2.34–5.91] respectively. Other secondary outcomes include: ICU mortality of 29.7%; in-hospital mortality of 61.7%; and 1-year mortality of 71.1%. Of the 46 patients that were discharged, 28 (60.9%) went home, 6 (13.0%) were transferred to community hospital or rehabilitation facility, 4 (8.7%) to nursing home, 3 (6.5%) to other hospitals and 5 (10.9%) required long term home mechanical ventilation. Twelve (26.1%) were dependent in activities of daily living and 13 (28.3%) were bedbound at discharge. Conclusions: Patients requiring PMV represent a distinct cohort of ICU patients with high mortality and high burden of care.