Characteristics and Outcomes of Ventilated Patients According to Time to Liberation from Mechanical Ventilation

A new classification of patients based on the duration of liberation of mechanical ventilation has been proposed. OBJECTIVES: To analyze outcomes based on the new weaning classification in a cohort of mechanically ventilated patients. METHODS: Secondary analysis included 2,714 patients who were weaned and underwent scheduled extubation from a cohort of 4,968 adult patients mechanically ventilated for more than 12 hours. MEASUREMENTS AND MAIN RESULTS: Patients were classified according to a new weaning classification: 1,502 patients (55%) as simple weaning,1,058 patients (39%) as difficult weaning, and 154 (6%) as prolonged weaning.Variables associated with prolonged weaning(.7d)were: severity at admission (odds ratio [OR] per unit of Simplified Acute Physiology Score II, 1.01; 95% confidence interval [CI], 1.001\u20131.02), duration of mechanical ventilation before first attempt of weaning (OR per day, 1.10; 95% CI, 1.06\u20131.13), chronic pulmonary disease other than chronic obstructive pulmonary disease (OR,13.23; 95% CI, 3.44\u201351.05), pneumonia as the reason to start mechanical ventilation (OR, 1.82; 95% CI, 1.07\u20133.08), and level of positive end-expiratory pressure applied before weaning (OR per unit,1.09; 95% CI, 1.04\u20131.14). The prolonged weaning group had a nonsignificant trend toward a higher rate of reintubation (P \ubc 0.08),tracheostomy (P \ubc 0.15), and significantly longer length of stay and higher mortality in the intensive care unit (OR for death, 1.97;95%CI, 1.17\u20133.31). The adjusted probability of death remained constant until Day 7, at which point it increased to 12.1%