Risk factors associated with development of ventilator associated pneumonia.

OBJECTIVE: To assess the risk factors associated with development of ventilator associated pneumonia (VAP).

DESIGN: A case control study.

PLACE AND DURATION OF STUDY: Intensive Care Unit (ICU) at the Aga Khan University Hospital, Karachi, between January 1999 and June 2000.

PATIENTS AND METHODS: All patients with assisted mechanical ventilation were assessed for the development of VAP. Risk factors associated with development of VAP were determined. Adult patients who developed pneumonia, 48 hours after ventilation, were called cases while those who did not develop pneumonia were called controls.

RESULTS: Seventy (28%) out of 250 mechanically ventilated patients developed VAP (rate of VAP was 26 cases per 1000 ventilator days). Shock during first 48 hours of ventilation (odds ratio (OR), 5.95; 95% confidence interval (CI), 2.83-12.52), transport out of ICU during mechanical ventilation (OR, 6.0; 95% CI, 2.92-12.37), re-intubation (OR, 4.23; 95% CI, 2.53-9.85), prior episode of aspiration of gastric content (OR, 3.07; 95% CI, 1.35-7.01), and use of antibiotics prior to intubation (OR,2.55; 95% CI, 1.20-5.41) were found to be independently associated with a higher risk of developing VAP. Gram negative organisms and Staphylococcus aureus were responsible for over 90% of cases. Patients with VAP had higher crude mortality rate (57.1%) compared with controls (32.2%).

CONCLUSION: Ventilator associated pneumonia is associated with a high mortality. This study has identified risk factors associated with VAP.