The Reality of Patients Requiring Prolonged Mechanical Ventilation: A Retrospective Multicenter Cohort Study

Context: The number of patients requiring prolonged mechanical ventilation (PMV) has increased over the last decade, generating a large population of chronically ill patients. Objective: To establish the incidence of PMV in four Intensive Care Units (ICUs), and to report different characteristics, hospital outcomes, and the impact of costs and services of PMV patients (mechanical ventilation dependency ≥ 21 days) compared with non-PMV patients (mechanical ventilation dependency < 21 days). Design, Setting, and Patients: A retrospective multicenter cohort study, including all patients admitted to four ICUs. Main Outcome Measures: Length of stay in the ICU, hospital, complications during ICU stay, and ICU and hospital mortality. Results: During study period, there were 5,287 admission episodes to the ICUs. Forty-one point five percent of these patients needed ventilatory support (n=2,197), and 218 met criteria for PMV (9.9%). Some complications developed during ICU stay, such as muscle weakness, pressure ulcers, bacterial nosocomial sepsis, candidemia, pulmonary embolism, and hyperactive delirium, were associated with a significantly higher risk of PMV. PMV patients had a significant increase in ICU mortality (absolute difference=14.2%, p<0.001), and in hospital mortality (absolute difference=19.1%, p<0.001); PMV group spent more days in the hospital after ICU discharge (26.9 ± 29.3 vs. 10.3 ± 20.4, p<0.001) and with higher costs. Conclusions: the classification of chronically critically ill patients according to the definition of PMV adopted by our study (mechanical ventilation dependency ≥21 days) identified patients with high risk for complications during ICU stay, high ICU and hospital stay, high death rates, as well as higher costs.