Contemporary ventilator management in patients with and at risk of ALI/ARDS

Respir Care. 2013 Apr;58(4):578-88. doi: 10.4187/respcare.01755.

Abstract

Background: Ventilator practices in patients at risk for acute lung injury (ALI) and ARDS are unclear. We examined factors associated with choice of set tidal volumes (VT), and whether VT < 8 mL/kg predicted body weight (PBW) relates to the development of ALI/ARDS.

Methods: We performed a secondary analysis of a multicenter cohort of adult subjects at risk of lung injury with and without ALI/ARDS at onset of invasive ventilation. Descriptive statistics were used to describe ventilator practices in specific settings and ALI/ARDS risk groups. Logistic regression analysis was used to determine the factors associated with the use of VT < 8 mL/kg PBW and the relationship of VT to ALI/ARDS development and outcome.

Results: Of 829 mechanically ventilated patients, 107 met the criteria for ALI/ARDS at time of intubation, and 161 developed ALI/ARDS after intubation (post-intubation ALI/ARDS). There was significant intercenter variability in initial ventilator settings, and in the incidence of ALI/ARDS and post-intubation ALI/ARDS. The median VT was 7.96 (IQR 7.14-8.94) mL/kg PBW in ALI/ARDS subjects, and 8.45 (IQR 7.50-9.55) mL/kg PBW in subjects without ALI/ARDS (P = .004). VT decreased from 8.40 (IQR 7.38-9.37) mL/kg PBW to 7.97 (IQR 6.90-9.23) mL/kg PBW (P < .001) in those developing post-intubation ALI/ARDS. Among subjects without ALI/ARDS, VT ≥ 8 mL/kg PBW was associated with shorter height and higher body mass index, while subjects with pneumonia were less likely to get ≥ 8 mL/kg PBW. Initial VT ≥ 8 mL/kg PBW was not associated with the post-intubation ALI/ARDS (adjusted odds ratio 1.30, 95% CI 0.74-2.29) or worse outcomes. Post-intubation ALI/ARDS subjects had mortality similar to subjects intubated with ALI/ARDS.

Conclusions: Clinicians seem to respond to ALI/ARDS with lower initial VT. Initial VT, however, was not associated with the development of post-intubation ALI/ARDS or other outcomes.

Trial registration: ClinicalTrials.gov NCT00889772.

Keywords: ARDS; acute lung injury; mechanical ventilation; mortality; tidal volume.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Lung Injury / etiology
  • Acute Lung Injury / mortality
  • Acute Lung Injury / therapy*
  • Adult
  • Aged
  • Body Mass Index
  • Body Weight
  • Cohort Studies
  • Female
  • Health Status
  • Humans
  • Length of Stay
  • Male
  • Middle Aged
  • Practice Patterns, Physicians'
  • Respiration, Artificial*
  • Respiratory Distress Syndrome / etiology
  • Respiratory Distress Syndrome / mortality
  • Respiratory Distress Syndrome / therapy*
  • Risk Factors
  • Tidal Volume

Associated data

  • ClinicalTrials.gov/NCT00889772