Nosocomial Tracheobronchitis in Mechanically Ventilated Patients: Frequency, Aetiology and Outcomes

Objective: The aim of this study was to determine the frequency, etiology, microbiological sen-sitivity and outcomes of nosocomial tracheobronchitis (NTB) in mechanically ventilated patients admitted in surgical intensive care unit. Methodology: A prospective observational study was conducted in the Surgical Intensive Care Unit (ICU), Department of Anaesthesiology, Civil Hospital Karachi from April 2009 to April 2010. All the patients on mechanical ventilator for more than 48 hours in the ICU were evalu-ated according to the criteria for the diagnosis of nosocomial tracheobronchitis (NTB). Out-comes of the patients were measured in terms of development of nosocomial pneumonia after NTB, length of ICU stay, duration of mechanical ventilation and mortality in the ICU. Results: Two hundred and eighteen patients were evaluated for this study. Nosocomial tracheobronchitis was diagnosed in 72 patients. The frequency of NTB was 33%. Sixteen types of or-ganisms were identified, 61.23% cases were poly-microbial, while in the remaining 39.7% cases single organism was isolated. The most common organism was gram negative Acinetobacter spp (51%), followed by Klebsiella spp (29%) and Pseudomonas aeruginosa (16.6%). Escherichia coli and other gram negative rods were 13.8 % and 11.4%, respectively. There were 4.16 % cases of MRSA isolated in patients who had positive cultures for gram negative organ-isms (poly-microbial). Ceftriaxone was given in 44% cases as empirical therapy and continued in 33% cases after microbial sensitivity and replaced in 11% cases after culture sensitivity to Cefiperazone + salbactum and in 14% cases cefiperazone was given in combination therapy. Imipenem was used in 28.5% of patients. Quinolones were used in 19% contaminated cases of gut surgeries. Nosocomial tracheobronchitis was significantly associated with increased length of ICU stay and longer duration of mechanical ventilation in our patients when compared to those patients who did not develop NTB (p<0.001). Moreover, out of 72 patients, 11 developed subsequent nosocomial pneumonia. There was no statistically significant difference noted in mortality rates among patients with NTB and without NTB (43% vs. 41%). The mortality was related to concomitant comorbitidies, primary cause and surgical outcomes. Conclusion: Nosocomial tracheobronchitis is a common infection in mechanically ventilated patients that significantly affects the development of pneumonia and length of ICU stay for the patients. This study was an insight to the state of NTB in an ICU setup. The higher frequency of NTB demands such studies to set protocols in every intensive care unit.