One hundred thirty (44.2%) of 294 patients hospitalized for
trauma and admitted to the
Surgical Intensive Care Unit for
mechanical ventilation developed hospital-acquired
bacterial pneumonia. The predominant pathogens isolated were gram-negative enteric bacilli (72%), but there was not an increase in mortality associated with gram-negative
pneumonia compared with similar patients without
pneumonia. Of the seven admission risk factors univariately associated with the development of acquired
bacterial pneumonia, only emergent intubation (p less than 0.001),
head injury (p less than 0.001),
hypotension on admission (p less than 0.001), blunt
trauma as the mechanism of injury (p less than 0.001), and Injury Severity Score (p less than 0.001) remained significant after stepwise logistic regression. Not surprisingly, as
mechanical ventilation is continued, the probability of
pneumonia emerging increases. The consequences of hospital-acquired
bacterial pneumonia are a significant seven-, five-, and two-fold increase in mechanically ventilated days,
intensive care, and
hospital stay, respectively. We conclude that the incidence of
hospital-acquired pneumonia in injured patients admitted to the ICU for
mechanical ventilation occurs in nearly half the patients, is associated with specific risk factors, and significantly increases morbidity but does not increase mortality.