Characteristics and outcomes of ventilated patients according to time to liberation from mechanical ventilation

Am J Respir Crit Care Med. 2011 Aug 15;184(4):430-7. doi: 10.1164/rccm.201011-1887OC.


Rationale: 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], 1.001–1.02), duration of mechanical ventilation before first attempt of weaning (OR per day, 1.10; 95% CI, 1.06–1.13), chronic pulmonary disease other than chronic obstructive pulmonary disease (OR,13.23; 95% CI, 3.44–51.05), pneumonia as the reason to start mechanical ventilation (OR, 1.82; 95% CI, 1.07–3.08), and level of positive end-expiratory pressure applied before weaning (OR per unit,1.09; 95% CI, 1.04–1.14). The prolonged weaning group had a nonsignificant trend toward a higher rate of reintubation (P ¼ 0.08),tracheostomy (P ¼ 0.15), and significantly longer length of stay and higher mortality in the intensive care unit (OR for death, 1.97;95%CI, 1.17–3.31). The adjusted probability of death remained constant until Day 7, at which point it increased to 12.1%.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Adult
  • Asthma / therapy
  • Chronic Disease
  • Cohort Studies
  • Follow-Up Studies
  • Humans
  • Intensive Care Units
  • Intubation
  • Length of Stay
  • Logistic Models
  • Lung Diseases / mortality
  • Lung Diseases / physiopathology
  • Lung Diseases / therapy*
  • Odds Ratio
  • Pneumonia / therapy
  • Positive-Pressure Respiration
  • Prospective Studies
  • Pulmonary Disease, Chronic Obstructive / therapy
  • Respiration, Artificial*
  • Retreatment
  • Risk Assessment
  • Severity of Illness Index
  • Time Factors
  • Tracheostomy
  • Treatment Outcome
  • Ventilator Weaning* / classification
  • Ventilator Weaning* / methods