Occult pneumothorax in blunt trauma: is there a need for tube thoracostomy?

Abstract

Occult pneumothorax (OPTX) is defined as air within the pleural cavity that is undetectable on normal chest X-rays, but identifiable on computed tomography. Currently, consensus is divided between tube thoracostomy and conservative management for OPTX. The aim of this retrospective study is to determine whether OPTX can be managed conservatively and whether any adverse events occur under conservative management. Data on all trauma patients from 1 Jan 2010 to 31 December 2012 were obtained from our hospital's trauma registry. All patients with occult pneumothorax who had chest X-ray (CXR) and any CT scan visualizing the thorax were included. The exclusion criteria included those with penetrating wounds; CXR showing pneumothorax, hemothorax, or hemopneumothorax; those with prophylactic chest tube insertion before CT; and those with no CT diagnosis of OPTX. The complications of these patients were analyzed to determine if tube thoracostomy is necessary for OPTX and whether not inserting it would alter the outcome significantly. A total of 1564 cases were reviewed and 83 patients were included. Of these 83 patients, 35 (42.2%) had tube thoracostomy after OPTX detection and 48 (57.8%) were observed initially. Patients who had tube thoracostomy had similar ISS compared to those without (median ISS 17 vs. 18.5, p=0.436). Out of the 48 patients who did not have tube thoracostomy on detection of an OPTX, 4 (8.3%) had complications. In the group of 35 patients who had tube thoracostomy on detection of an OPTX, 7 (20%) had complications. Of the 83 patients, a total of 12 patients had IPPV, of which 7 (58.3%) had tube thoracostomy and 5 (41.7%) did not. Patients who had tube thoracostomy under our care have a statistically significant likelihood of experiencing any complication compared to those without tube thoracostomy (odds ratio 9.92. The median length of stay was also longer (13days) in those who had tube thoracostomy compared to those without (5days) (p value =0.008). Our study suggests that patients with OPTX can be managed conservatively with close monitoring, but only in areas with ready access to emergency facilities should any adverse events occur.