Mechanical ventilation with low tidal volumes is recommended for all patients with acute respiratory distress syndrome and may be beneficial to other intubated patients, yet consistent implementation remains difficult to obtain. Using detailed electronic health record data, we examined patterns of tidal volume administration, the effect on clinical outcomes, and alternate metrics for evaluating low tidal volume compliance in clinical practice.
Observational cohort study.
Six ICUs in a single hospital system.
Adult patients who received invasive mechanical ventilation more than 12 hours.
Tidal volumes were analyzed across 1,905 hospitalizations. Although mean tidal volume was 6.8 mL/kg predicted body weight, 40% of patients were exposed to tidal volumes greater than 8 mL/kg predicted body weight, with 11% for more than 24 hours. At a patient level, exposure to 24 total hours of tidal volumes greater than 8 mL/kg predicted body weight was associated with increased mortality (odds ratio, 1.82; 95% CI, 1.20–2.78), whereas mean tidal volume exposure was not (odds ratio, 0.87/1 mL/kg increase; 95% CI, 0.74–1.02). Initial tidal volume settings strongly predicted exposure to volumes greater than 8 mL/kg for 24 hours; the adjusted rate was 21.5% when initial volumes were greater than 8 mL/kg predicted body weight and 7.1% when initial volumes were less than 8 mL/kg predicted body weight. Across ICUs, correlation of mean tidal volume with alternative measures of low tidal volume delivery ranged from 0.38 to 0.66.
Despite low mean tidal volume in the cohort, a significant percentage of patients were exposed to a prolonged duration of high tidal volumes which was correlated with higher mortality. Detailed ventilator records in the electronic health record provide a unique window for evaluating low tidal volume delivery and targets for improvement.
1Department of Medicine, University of Michigan, Ann Arbor, MI.
2Institute for Healthcare Policy & Innovation, University of Michigan, Ann Arbor, MI.
3Department of Medicine, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY.
4Department of Epidemiology and Population Health, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY.
5Adult Respiratory Care, University of Michigan Medical Center, Ann Arbor, MI.
6VA Center for Clinical Management Research, Ann Arbor, MI.
7Institute for Social Research, Ann Arbor, MI.
*See also p. 131.
Dr. Sjoding contributed to the study design, analysis and interpretation of data, writing and revising the article, and approval of the final article. Drs. Gong, Haas, and Iwashyna contributed to the study design, analysis and interpretation of data, revising the article for important intellectual content, and approval of the final article.
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Supported, in part, by grants to Dr. Sjoding from the National Heart, Lung, and Blood Institute K01HL136687 and Dr. Iwashyna from the Department of Veterans Affairs Health Services Research & Development Services - IIR 13–079. This work does not necessarily represent the views of the U.S. Government or Department of Veterans Affairs.
Dr. Sjoding’s institution received funding from National Institute of Health (NIH), and he received support for article research from the NIH. Dr. Iwashyna disclosed government work. The remaining authors have disclosed that they do not have any potential conflicts of interest.
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