Prospective evaluation of early follow-up chest radiography after penetrating thoracic injury.

BACKGROUND: In asymptomatic patients with penetrating thoracic trauma and a normal initial chest x-ray, successive prospective trials have decreased the minimum observation period required for exclusion of significant injury from 6 to 3 h. Despite the quality of these studies, this interval remains arbitrary and the true requisite observation time for safe discharge remains unknown. The current study evaluates the ability of "early" repeat chest x-ray, at intervals approaching 1 h, to exclude clinically significant injury.

METHODS: Eighty-eight, asymptomatic patients with penetrating chest trauma and normal initial chest radiographs were prospectively enrolled in this study. All patients received an "early" follow-up chest x-ray, at a median interval of 1 h and 34 min (interquartile range: 1 h 35 min to 2 h 22 min), and a second repeat x-ray at a "delayed" interval no earlier than 3 h postadmission. Radiographic abnormalities in clinically stable patients were followed with serial examination and repeat imaging for a minimum of 6 h. All patients received both "early" and "delayed" repeat CXRs with no patient discharged before full assessment.

RESULTS: One of the 88 patients with initially normal chest x-ray underwent tube thoracostomy at the discretion of the attending surgeon before any repeat imaging. Of the remaining patients, 4 of 87 (4.6 %) demonstrated radiographic abnormalities on "early" repeat imaging. Two patients had pneumothoraces, successfully managed without intervention; the remaining two demonstrated evidence of hemothorax, subsequently undergoing tube thoracostomy. Two more patients (2.3 %) developed pneumothoraces on "delayed" imaging, both successfully observed without intervention.

CONCLUSIONS: In asymptomatic patients with penetrating thoracic trauma and normal initial chest radiographs, "early" repeat chest x-ray, at intervals approaching 1 h, appears sufficient to exclude clinically significant pathology and to allow safe patient discharge.