Does gastric volume in trauma patients identify a population at risk for developing pneumonia and poor outcomes?

Trauma patients may have full stomachs or impaired airway reflexes that place them at risk for aspiration and pneumonia. Our hypothesis was that trauma patients with larger gastric volumes as measured by abdominal computed tomography (CT) at admission have higher rates of pneumonia and worse outcomes.

We matched an initial cohort of 81 trauma patients with an admission CT of the abdomen and a diagnosis of pneumonia by Injury Severity Score and Abbreviated Injury Score of the head and chest with a control group of 81 trauma patients without pneumonia. We estimated gastric volumes on CT and compared variables using chi-square, t-tests, receiver operating curve analysis, and regression analysis.

Patients with pneumonia had larger gastric volumes than those without pneumonia (879 cm(3)versus 704 cm(3); P = 0.04). Receiver operating curve analysis gave a gastric volume threshold value of 700 cm(3) as a predictor of pneumonia. Patients with a gastric volume ≥ 700 cm(3) had more pneumonia (61% versus 41%; P = 0.01), stayed longer in the hospital (27.6 versus 19.7 d; P < 0.05) and the intensive care unit (18.4 versus 12.5 d; P = 0.01), required more days on the ventilator (18.1 versus 12.0 d; P = 0.02), and had a trend toward increased mortality (17% versus 11%; P = 0.2). On multivariate analysis, nasogastric or orogastric tube (odds ratio 3.0; P = 0.004) and gastric volume >700 cm(3) (odds ratio 2.7; P = 0.004) were independent predictors of pneumonia.

Trauma patients who developed pneumonia had larger initial gastric volumes. A straightforward estimate of gastric volume on admission abdominal CT may predict patients at risk for developing pneumonia and poor outcomes. Clinicians should be especially vigilant in taking precautions against pneumonia and have a lower threshold for suspecting pneumonia in patients with abdominal CT gastric volumes ≥ 700 cm(3).