Survival in Patients Receiving Prolonged Ventilation: Factors that Influence Outcome

Background: Prolonged mechanical ventilation is increasingly common. It is expensive and associated with significant morbidity and mortality. Our objective is to comprehensively characterize patients admitted to a Ventilator Rehabilitation Unit (VRU) for weaning and identify characteristics associated with survival. Methods: 182 consecutive patients over 3.5 years admitted to Temple University Hospital (TUH) VRU were characterized. Data were derived from comprehensive chart review and a prospectively collected computerized database. Survival was determined by hospital records and social security death index and mailed questionnaires. Results: Upon admission to the VRU, patients were hypoalbuminemic (albumin 2.3 +/- 0.6 g/dL), anemic (hemoglobin 9.6 +/- 1.4 g/dL), with moderate severity of illness (APACHE II score 10.7 + 4.1), and multiple comorbidities (Charlson index 4.3 + 2.3). In-hospital mortality (19%) was related to a higher Charlson Index score (P = 0.006; OR 1.08-1.6), and APACHE II score (P = 0.016; OR 1.03-1.29). In-hospital mortality was inversely related to admission albumin levels (P = 0.023; OR 0.17-0.9). The presence of COPD as a comorbid illness or primary determinant of respiratory failure and higher VRU admission APACHE II score predicted higher long-term mortality. Conversely, higher VRU admission hemoglobin was associated with better long term survival (OR 0.57-0.90; P = 0.0006). Conclusion: Patients receiving prolonged ventilation are hypoalbuminemic, anemic, have moderate severity of illness, and multiple comorbidities. Survival relates to these factors and the underlying illness precipitating respiratory failure, especially COPD.