Assessment of Risk Factors for Ventilator Associated Pneumonia in the Medical Intensive Care Unit

Aim: To detect the risk factors for ventilator associated pneumonia (VAP) and role of ventilator parameters in the development of VAP in a Medical Intensive Care Unit (MICU). Materials and Methods: This study was performed prospectively in Gevher Nesibe Hospital MICU of Erciyes University Medical Faculty between 1 January, 2003 and 1 April, 2004. The patients, who were 16 years old and over, who had been ventilated with a mechanical ventilator for more than 24 hours and who had no pulmonary infection, were included in the study. The patients' demographic characteristics, risk factors and ventilator parametres (PEEP, ventilation mode, tidal volume, FiO(2), PEAK, mean pressure, plateau pressure) were recorded. Also the hospitalization period before mechanical ventilation and up to pneumonia development, total time of ICU admission and the time of weaning were recorded. Results: A total of 106 patients were included in the study and VAP developed in 49 (46.2%) patients. When risk factors for VAP were evaluated in the univariate analysis, it was found that there was a statistically significant relationship between previous sepsis (OR= 2.557, 95% CI=1.153- 5.671, p=0.021), sedative drug usage (OR=2.876, 95% CI=1.168-7.075, p=0.021), tracheostomy (0R=3.602, 95% CI=1.446-8.972, p=0.006), PIP (OR=0.946, 95% CI=0.898-0.997, p=0.036), number of aspirations (OR=1.778, 95% CI=1.238-2.552, p=0.002), enteral nutrition (OR=5.440, 95% CI=2.197-13.471, p=0.000) and nasogastric tube (OR=2.510, 95% CI=1.138-5.537, p=0.023). When multivariate analysis was performed, previous sepsis (OR=6.291, 95% CI=1.944-20.356, p=0.002), sedative drug usage (OR=3.719, 95% CI=1.109-12.476, p=0.033), number of aspiration (OR=2.107, 95% CI=1.313-3.381, p=0.002) and enteral nutrition (OR=3.586, 95% CI=1.063-12.100, p=0.040) were determined to be independent risk factors. Ventilation modes and ventilation parameters had no effect on the development of pneumonia with multivariate logistic regression analysis. The duration of hospitalization in patients with VAP was longer than those who had no VAP (p<0.05). The crude mortality rate was 81.6%. There was no statistically significant relationship in mortality rates between the patients with VAP and those without VAP (p>0.05). Conclusion: Sepsis, sedative drug usage, number of aspirations and enteral nutrition were established as risk factors, whereas ventilation modes and ventilation parameters had no effect on the development of pneumonia. Avoiding unnecessary aspiration and sedation, rapid diagnosis and treatment of infections in other systems will be effective in the prevention of VAP.