Pneumomediastinum and pneumopericardium following blunt thoracic trauma: much ado about nothing?

PURPOSE: Pneumomediastinum is the hallmark of intrathoracic aerodigestive trauma, but rare following blunt injury.

AIM: review of blunt thoracic trauma (BTC) for the incidence and outcome of patients with pneumomediastinum or pneumopericardium (PM/PC) on Computerised Tomographic scanning.

METHODS: Admissions to the level I trauma ICU at IALCH, Durban, ZA following BTC from April 2007 to March 2014. Patients with Chest-CT-scan were analysed. Variables included age, sex, mechanism of injury, and Injury Severity Score (ISS). Specific injury patterns: isolated thoracic trauma, flail chest, bilateral injury and presence of haemothorax or pneumothorax were analysed.

RESULTS: Three hundred and eighty-nine patients were included. Males (70.9%) accounted for the majority of patients. The median Injury Severity Score was 32 (IQR 24-41). Motor vehicle collisions accounted for 94% of injury mechanisms. Twenty-three (5.9%) were identified with pneumomediastinum, 6 (1.5%) with both pneumomediastinum and pneumopericardium, and 1 (0.2%) with isolated pneumopericardium. No patient required surgery for thoracic trauma. Increasing age (p < 0.001) and a flail chest (p = 0.005) were significant associations. The mortality rate was almost identical in those with or without air within the mediastinum. No patient died from a missed mediastinal aero-digestive injury.

CONCLUSION: The presence of PM/PC following BTC is incidental and benign. Increased injury severity with a flail chest is associated with a significant increase in the presence of free gas within the mediastinum. In the absence of complications, no obvious injury to the intrathoracic aero-digestive tract on CT scanning, and no difference in mortality, a conservative management policy is warranted.