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Clinical and economic consequences of ventilator-associated pneumonia: A systematic review

Safdar, Nasia MD, MS; Dezfulian, Cameron MD; Collard, Harold R. MD; Saint, Sanjay MD, MPH

doi: 10.1097/01.CCM.0000181731.53912.D9
Continuing Medical Education Article

Background: Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in critically ill patients. The clinical and economic consequences of VAP are unclear, with a broad range of values reported in the literature

Objective: To perform a systematic review to determine the incidence of VAP and its attributable mortality rate, length of stay, and costs.

Data Source: Computerized PUBMED and MEDLINE search supplemented by manual searches for relevant articles, limited to articles published after 1990.

Study Selection: English-language observational studies and randomized trials that provided data on the incidence of VAP were included. Matched cohort studies were included for calculation of attributable mortality rate and length of stay.

Data Extraction: Data were extracted on patient population, diagnostic criteria for VAP, incidence, outcome, type of intensive care unit, and study design.

Data Synthesis: The cumulative incidence of VAP was calculated by combining the results of several studies using standard formulas for combining proportions, in which the weighted average and variance are calculated. Results from studies comparing intensive care unit and hospital mortality due to VAP, additional length of stay, and additional days of mechanical ventilation were pooled using a random effects model, with assessment of heterogeneity.

Results: Our findings indicate a) between 10% and 20% of patients receiving >48 hrs of mechanical ventilation will develop VAP; b) critically ill patients who develop VAP appear to be twice as likely to die compared with similar patients without VAP (pooled odds ratio, 2.03; 95% confidence interval, 1.16–3.56); c) patients with VAP have significantly longer intensive care unit lengths of stay (mean = 6.10 days; 95% confidence interval, 5.32–6.87 days); and d) patients who develop VAP incur ≥$10,019 in additional hospital costs.

Conclusions: Ventilator-associated pneumonia occurs in a considerable proportion of patients undergoing mechanical ventilation and is associated with substantial morbidity, a two-fold mortality rate, and excess cost. Given these findings, strategies that effectively prevent VAP are urgently needed.

LEARNING OBJECTIVES On completion of this article, the reader should be able to:

  1. Define the incidence of ventilator-associated pneumonia (VAP) in mechanically ventilated patients.
  2. Explain the economic consequences of VAP.
  3. Use this information in a clinical setting.

All authors have disclosed that they have no financial relationships or interests in any commercial companies pertaining to this educational activity.

Wolters Kluwer Health has identified and resolved all faculty conflicts of interest regarding this educational activity.

Visit the Critical Care Medicine Web site ( for information on obtaining continuing medical education credit.

Clinical Instructor, Section of Infectious Diseases, Department of Medicine, University of Wisconsin Medical School, Madison, Wisconsin (NS); Clinical Fellow, the Critical Care Medicine Department, National Institutes of Health, Bethesda, MD, and Division of Pediatric Anesthesia and Critical Care, Johns Hopkins Hospital, Baltimore, MD (CD); Assistant Professor of Medicine, University of California, San Francisco, CA (HRC); Research Investigator, Ann Arbor VA Medical Center, Director, UM/VA Patient Safety Enhancement Program, Associate Professor of Medicine, University of Michigan Medical School, Senior Associate Division Chief, Division of General Medicine, University of Michigan, Ann Arbor, Michigan (SS).

This work was supported, in part, by a Patient Safety Fellowship award provided by C.R. Bard and the Research Foundation for the Prevention of Complications Associated with Health Care. Dr. Saint is supported by a Career Development Award from the Health Services Research & Development Program of the Department of Veterans Affairs and a Patient Safety Developmental Center Grant from the Agency for Healthcare Research and Quality (P20-HS11540).

Address requests for reprints to: Nasia Safdar, MD, MS, University of Wisconsin Madison, H4/572 Section of Infectious Diseases, 600 Highland Avenue, Madison, WI 53792. E-mail:

© 2005 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins