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

ABSTRACT

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.