Analysis of hypoxemia in early ventilator-associated pneumonia secondary to Haemophilus in trauma patients

Haemophilus species bacteria (HSB) are known pathogens responsible for early pneumonia in intubated trauma patients. The primary goal of this study was to examine the incidence and extent of hypoxemia in intubated trauma patients who develop early ventilator-associated pneumonia (VAP) secondary to HSB. On the basis of our clinical experiences, we hypothesized that patients with Haemophilus species bacteria pneumonia (HSBP) would have a high rate of hypoxemia but that the effect would be transient. Methods: Retrospective review of intubated trauma patients from an urban level I trauma center with HSBP diagnosed by deep tracheal aspirate or bronchoalveolar lavage from April 2007 to November 2012. Collected variables included day of HSBP diagnosis; PaO₂ to F_IO₂ ratio (P:F) at HSBP diagnosis as well as HSBP day three and HSBP day seven; injury severity score (ISS) and its component parts; admission Glasgow Coma Scale (GCS) score; and mortality. Hypoxemia was defined as P:F <200. χ² Tests were utilized to assess factors that differed between hypoxemic and non-hypoxemic patients; data are presented as median (interquartile range, IQR). Results: Sixty-nine patients were identified (80% male; age, 35y [range, 24-49]; ISS 27 [9-59]). Diagnosis of HSBP occurred early (hospital day 4 [range, 3-5]). Forty-three percent of patients had acute respiratory distress syndrome (ARDS) on HSBP day 1; this decreased to 26% on day three and to 30% on day seven. Forty patients (77%) had a tracheostomy performed. Patients with hypoxemia were significantly less likely to have a severe head injury (GCS<9), p<0.05. Patients with hypoxemia had similar hospital length of stay and mortality to patients who did not develop hypoxemia. Conclusion: Haemophilus species bacteria pneumonia in trauma patients is associated with high rates of transient hypoxemia and a high tracheostomy rate, although subsequent outcomes are not affected. Patients with head injuries had a lower incidence of hypoxemia from pneumonia.