RISK-FACTORS FOR EARLY-ONSET PNEUMONIA IN TRAUMA PATIENTS

Study objectives: The aim of the study was to identify risk factors fo r early onset pneumonia (EOP) in trauma patients, in order to seek pos sible intervention strategies. Study population: Participants included 124 consecutive trauma patients admitted to a general intensive care unit (ICU) of a university hospital from December 1990 to February 199 2 inclusive. Data collection: The following data were prospectively co llected for each hat;ent: demographics, severity of trauma according t o the abbreviated injury scale (AIS), severity of coma according to th e Glasgow coma scale (GCS), presence of pneumothorax, pulmonary contus ion, rib fractures, hemothorax, and mechanical ventilation. All patien ts were monitored daily during the ICU stay for the onset of pneumonia , sepsis syndrome, septic shock and adult respiratory distress syndrom e (ARDS). Criteria for the diagnosis of pneumonia were: core temperatu re of greater than 38.3 degrees C, a WBC count of 10,000 cells/mm(3), purulent tracheobronchial secretions, a worsening of pulmonary gas exc hange, and persistent pulmonary infiltrates. An patients with suspecte d pneumonia underwent quantitative bronchoalveolar lavage (BAL) as wel l as blood cultures; BAL cultures were considered positive when they s howed bacterial growth greater than 1 x 10(5) colony-forming unit (cfu )/ml or less than 10(5), but with the same microorganism isolated in b lood cultures. Pneumonia occurring within the first 96 h after trauma was considered EOP. Data analysis: A stepwise logistic regression anal ysis was carried out in order to identify factors independently associ ated with an increased risk of EOP and late onset pneumonia (LOP). Res ults: Overall mortality was 43.5 percent: mortality increased by age a nd AIS score. Forty one patients (33.1 percent) developed pneumonia: 2 6 (63.4 percent) were EOP and 15 (36.6 percent) were LOP. In the univa riate analysis, an age greater than 40 years, the presence of pulmonar y contusion, AIS of more than 4 for thorax and of more than 9 for abdo men, and the absence of mechanical ventilation (MV) during the first 4 days of hospitalization or MV lasting less than 24 h were significant ly associated with an increased risk of acquiring EOP. Logistic regres sion analysis showed that the strongest risk factor for EOP was a comb ined severe abdominal and thoracic trauma, which increased the risk of EOP by 11 times; an age of more than 40 years and MV of less than 24 h during the first 4 days of hospitalization were also independent ris k factors for EOP. Factors associated with LOP were an AIS score of mo re than 4 for abdomen and a length of MV of more than 5 days. Conclusi on: Tn a trauma population, a combined severe abdominal and thoracic t rauma represents a major risk factor for EOP. Mechanical ventilation a dministered during the first days after trauma seems to reduce the ris k of EOP. As reported in previous studies, mechanical ventilatory supp ort lasting more than 5 days is associated with an increased risk of L OP.