Skip to main content Accessibility help

Descriptive Epidemiology and Attributable Morbidity of Ventilator-Associated Events

  • Michael Klompas (a1) (a2), Ken Kleinman (a1), Michael V. Murphy (a1) and for the CDC Prevention Epicenters Program



The Centers for Disease Control and Prevention implemented new surveillance definitions for ventilator-associated events (VAEs) in January 2013. We describe the epidemiology, attributable morbidity, and attributable mortality of VAEs.


Retrospective cohort study.


Academic tertiary care center.


All patients initiated on mechanical ventilation between January 1, 2006, and December 31, 2011.


We calculated and compared VAE hazard ratios, antibiotic exposures, microbiology, attributable morbidity, and attributable mortality for all VAE tiers.


Among 20,356 episodes of mechanical ventilation, there were 1,141 (5.6%) ventilator-associated condition (VAC) events, 431 (2.1%) infection-related ventilator-associated complications (IVACs), 139 (0.7%) possible pneumonias, and 127 (0.6%) probable pneumonias. VAC hazard rates were highest in medical, surgical, and thoracic units and lowest in cardiac and neuroscience units. The median number of days to VAC onset was 6 (interquartile range, 4–11). The proportion of IVACs to VACs ranged from 29% in medical units to 42% in surgical units. Patients with probable pneumonia were more likely to be prescribed nafcillin, ceftazidime, and fluroquinolones compared with patients with possible pneumonia or IVAC-alone. The most frequendy isolated organisms were Staphylococcus aureus (29%), Pseudomonas aeruginosa (14%), and Enterobacter species (7.9%). Compared with matched controls, VAEs were associated with more days to extubation (relative rate, 3.12 [95% confidence interval (CI), 2.96–3.29]), more days to hospital discharge (relative rate, 1.46 [95% CI, 1.37–1.55]), and higher hospital mortality risk (odds ratio, 1.98 [95% CI, 1.60–2.44]).


VAEs are common and morbid. Prevention strategies targeting VAEs are needed.


Corresponding author

Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, 133 Brookline Avenue, 6th Floor, Boston, MA 02215 (


Hide All
1. Centers for Disease Control and Prevention (CDC). Ventilator-Associated Event Protocol. Atlanta: CDC, 2013. Accessed February 25, 2013.
2. Magill, SS, Fridkin, SK. Improving surveillance definitions for ventilator-associated pneumonia in an era of public reporting and performance measurement. Clin Infect Dis 2012;54(3)378380.
3. Klompas, M. Complications of mechanical ventilation: the CDC's new surveillance paradigm. N Engl J Med 2013;368(16): 14721475.
4. Klompas, M, Kleinman, K, Platt, R. Development of an algorithm for surveillance of ventilator-associated pneumonia with electronic data and comparison of algorithm results with clinician diagnoses. Infect Control Hosp Epidemiol 2008;29(l)3137.
5. Klompas, M, Khan, Y, Kleinman, K, et al. Multicenter evaluation of a novel surveillance paradigm for complications of mechanical ventilation. PLoS ONE 2011;6(3):el8062.
6. Klompas, M, Kleinman, K, Khan, Y, et al. Rapid and reproducible surveillance for ventilator-associated pneumonia. Clin Infect Dis 2012;54:370377.
7. Klompas, M, Magill, S, Robicsek, A, et al. Objective surveillance definitions for ventilator-associated pneumonia. Crit Care Med 2012;40(12)31543161.
8. Prospero, E, Illuminati, D, Marigliano, A, et al. Learning from Galileo: ventilator-associated pneumonia surveillance. Am JRes-pir Crit Care Med 2012;186(12)13081309.
9. Hayashi, Y, Morisawa, K, Klompas, M, et al. Toward improved surveillance: the impact of ventilator-associated complications on length of stay and antibiotic use in patients in intensive care units. Clin Infect Dis 2013;56(4)471477.
10. Muscedere, J, Sinuff, T, Heyland, D, et al. The clinical impact and preventability of ventilator-associated conditions in critically ill mechanically ventilated patients. Chest 2013:144(5)14531460.
11. Elixhauser, A, Steiner, C, Harris, DR, Coffey, RM. Comorbidity measures for use with administrative data. Med Care 1998;36(1): 8-27.
12. Charlson, ME, Pompei, P, Ales, KL, MacKenzie, CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987;40(5)373383.
13. Hilbe, J. Negative Binomial Regression. 2nd ed. Cambridge: Cambridge University Press, 2011.
14. Brown, AJ, Prescott, C. Applied Mixed Models in Medicine. Chicester: Wiley, 2006.
15. Little, R, Rubins, D. Statistical Analysis with Missing Data. New York: Wiley, 1987.
16. Dudeck, MA, Horan, TC, Peterson, KD, et al. National Healthcare Safety Network (NHSN) Report, data summary for 2010, device-associated module. Am J Infect Control 2011;39(10)798816.
17. Cook, DJ, Walter, SD, Cook, RJ, et al. Incidence of and risk factors for ventilator-associated pneumonia in critically ill patients. Ann Intern Med 1998;129(6)433440.
18. Koulenti, D, Lisboa, T, Brun-Buisson, C, et al. Spectrum of practice in the diagnosis of nosocomial pneumonia in patients requiring mechanical ventilation in European intensive care units. Crit Care Med 2009;37(8)23602368.
19. Sievert, DM, Ricks, P, Edwards, JR, et al. Antimicrobial-resistant pathogens associated with healthcare-associated infections: summary of data reported to the national healthcare safety network at the centers for disease control and prevention, 2009-2010. Infect Control Hosp Epidemiol 2013;34(1)114.
20. Papazian, L, Thomas, P, Garbe, L, et al. Bronchoscopic or blind sampling techniques for the diagnosis of ventilator-associated pneumonia. Am } Respir Crit Care Med 1995;152(6)19821991.
21. Torres, A, el-Ebiary, M, Padro, L, et al. Validation of different techniques for the diagnosis of ventilator-associated pneumonia: comparison with immediate postmortem pulmonary biopsy. Am J Respir Crit Care Med 1994;149(2)324331.
22. Marquette, CH, Copin, MC, Wallet, F, et al. Diagnostic tests for pneumonia in ventilated patients: prospective evaluation of diagnostic accuracy using histology as a diagnostic gold standard. Am J Respir Crit Care Med 1995;151(6)18781888.
23. Kirtland, SH, Corley, DE, Winterbauer, RH, et al. The diagnosis of ventilator-associated pneumonia: a comparison of histologic, microbiologic, and clinical criteria. Chest 1997;112(2)445457.
24. Papazian, L, Autillo-Touati, A, Thomas, P, et al. Diagnosis of ventilator-associated pneumonia: an evaluation of direct examination and presence of intracellular organisms. Anesthesiology 1997;87(2)268276.
25. Fabregas, N, Ewig, S, Torres, A, et al. Clinical diagnosis of ventilator associated pneumonia revisited: comparative validation using immediate post-mortem lung biopsies. Thorax 1999; 54(10)867873.
26. Klompas, M. Ventilator-associated events surveillance: a patient safety opportunity. Curr Opin Crit Care 2013;19(5)424431.


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed