The utilization of mechanical ventilation has increased dramatically in the past few decades. Many of the patients who are mechanically ventilated are over 65 years of age and consume a disproportionate amount of health care resources. Better information is needed on the long term outcome, including quality of life (QOL) and health service utilization, of mechanically ventilated patients. The impacts of risk factors such as prehospital functional status, age, severity of illness, co-morbidities and durations of illness on long-term mortality and QOL needs to be evaluated. The proposed prospective study is designed to describe the long term (i.e., 1 year) outcomes of patients receiving 48+ hours of mechanical ventilation. The study will recruit approximately 480 adult patients under age 65 and 360 patients aged 65+ at the University of Pittsburgh Medical Center (UPMC) over a 2 and 1/2 year period. Data on ICU and hospital course will be recorded. Follow-up interviews with survivors will be conducted at 1 month, 6 months and 1 year after recruitment. The proposal aims to: (1) examine the long-term (up to 1 year) survival and QOL of patients requiring prolonged (48+ hours) mechanical ventilation; (2) measure resource utilization and caregiver burden for these patients; (3) estimate the independent effects of pre-hospital functional status, age, and severity/duration of illness on mortality, resource utilization, QOL and caregiver burden; and (4) address these same questions in an exploratory fashion for disease-specific subgroups. This study will provide unique information on the natural course of patients receiving mechanical ventilation. The data from this study will provide the basis for development and evaluation of a prognostic model and its impact on clinical decision making.