Survival in Patients Receiving Prolonged Ventilation: Factors that Influence Outcome

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.

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.

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).

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.