A Comparative Study of Ventilator-Associated Pneumonia and Ventilator Associated Tracheobronchitis: Incidence, Outcome, Risk Factors

K. V. Y. Babu, V. L. Jayasimha, K. G. Basavarajappa,  A. Kumar, K. G. R. Kumar, H. P. Niranjan and V. Vijayanath

Department of Microbiology, SS Institute of Medical Sciences and Research Centre, Jnanashankara, NH-4 Bypass road, Davangere - 577 005 India.

ABSTRACT: Background Ventilator associated tracheobronchitis (VAT) and Ventilator associated pneumonia (VAP) are common in endotracheally intubated and mechanically ventilated patients. Limited data available on review of literature regarding comparative studies of VAT and VAP from Indian subcontinent necessitated the present study. Objectives The present comparative study was conducted with an objective of determining incidence, etiology and associated risk factors of VAT and VAP. Material and Methods Consecutive non duplicated endotracheal aspirate cultures from 870 patients on ventilator for more than 48 hours were included in the present study. VAT and VAP were diagnosed with standard clinical and laboratory criteria. Patients receiving noninvasive pressure ventilation and patients with tracheostomy on ICU admission were excluded from the present study. Organism identification and antimicrobial susceptibility testing was done by standard laboratory procedures. Statistical analysis was done by Student “t” test and “z” test for proportions. Results Among 870 intubated patients, an incidence of 10.80%, 14.9% and 7.81% was observed for colonizers, Ventilator associated tracheobronchitis (VAT) and Ventilator associated pneumonia respectively. Mean ±SD duration of hospital stay was 12±2.1 and 16±11.2 days respectively for VAT and VAP without statistically significant difference in age and sex distribution. P. aeruginosa , K. pneumoniae and Acinetobacter baumanii were the most common pathogens of VAT and VAP. 20.35% (35/172) cases (VAT and VAP) were due to pan drug resistant isolates. Imipenem resistance of, 21.43%,33.3% and 44.82% among P. aeruginosa, K. pneumoniae and Acinetobacter baumanii respectively was observed . Sixteen antibiogram types of different pathogens with high resistance to Cefotaxime with no significant difference in antimicrobial susceptibility were observed among VAT and VAP pathogens. Crude mortality among VAP patients was higher 38.24% (26/68) than in VAT patients, 6.15% (8/130)(P< 0.001). Association of Prior imipenem therapy, Septic shock, Steroid therapy and Diabetes mellitus with VAP was highly significant. Conclusions VAT and VAP continue to be major challenges to the critical care physicians caused by most common pathogens P. aeruginosa, K. pneumoniae and Acinetobacter baumanii. VAP results in higher crude mortality than VAT. VAT and VAP cases are caused by several distinct antibiogram types of most common pathogens emerging and persisting in the ICUs. Predisposing risk factors are more frequently associated with VAP than VAT. Knowledge of the important risk factors predisposing to VAP may prove to be useful in implementing simple and effective preventive measures including non-invasive ventilation, precaution during emergency intubation, minimizing the occurrence of re-intubation, avoidance of accidental extubations as far as possible.

KEYWORDS: Ventilator associated tracheobronchitis (VAT); Ventilator associated pneumoniae (VAP)

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