Delayed Pneumothorax and Repeat Chest X-ray After Penetrating Thoracic Injury

Abstract & Commentary

Source: Shatz DV, et al. Efficacy of follow-up evaluation in penetrating thoracic injuries: 3- vs. 6-hour radiographs of the chest. J Emerg Med 2001:20:281-284.

The incidence of delayed pneumothorax (PTX) resulting from penetrating injuries of the chest has been reported to be as high as 12%. In most hospitals, serial chest x-rays (CXRs) are used to manage patients with penetrating chest trauma without PTX on initial radiograph. The suggested time interval for performing follow-up CXR is variable, ranging from six to 48 hours. Kerr and coworkers validated the use of a six-hour follow-up CXR to eliminate the risk of delayed PTX.1

This study examined the possibility of shortening the time period to follow-up CXR from six to three hours in patients with penetrating chest injuries. All patients with penetrating wounds that were bounded by the clavicles, the base of the neck superiorly, and the costal margin and iliac crest posteriorly were included if they were asymptomatic on arrival to the emergency department (ED), had no PTX or hemothorax on initial CXR, and did not require immediate admission to the intensive care unit (ICU) or operating room. Enrolled patients had initial, three-hour, and six-hour expiratory CXRs during the ED stay. A CT was performed only if intra-abdominal injury was suspected. Wound care was provided as necessary. Patients were discharged if the results of all CXRs and physical examinations were negative. All patients were telephoned on the day following the injury and given follow-up appointments in the trauma clinic.

Over 15 months, 116 asymptomatic patients with negative initial CXR were enrolled. Ninety-three were victims of stabbings, 23 were victims of gunshot wounds, and 22 sustained multiple penetrating injuries to the thorax. Two patients had a negative initial CXR, but demonstrated PTX on CT scan, and were dropped from the study. One patient had a negative initial CXR, but developed a PTX during the three-hour study and required tube thoracostomy. None of the remaining patients developed a PTX on the six-hour CXR. Six patients left against medical advice (AMA) prior to the completion of all three CXRs. Of these, two had follow-up with no sign of PTX and four patients were lost to any follow-up. Nine patients were admitted prior to the six-hour CXR, but all had negative in-house CXRs within 24 hours. Nine patients were discharged before the six-hour film, of which five had no problems on follow-up and four were lost to follow-up.

The authors conclude that the six-hour CXR offers no additional information that was not available from the three-hour CXR. They state that asymptomatic patients with negative initial and three-hour radiographs are safe for discharge.

Comment by Jacob W. Ufberg, MD

This study seems to validate a rule that will reduce the length of stay for patients with seemingly minor penetrating torso trauma. It also will help reduce the number of patients who leave AMA prior to being "cleared" by serial radiographs. One drawback of this study is the number of patients who were lost to follow-up. The authors could not help that some of the patients left AMA; however, the study would have been "cleaner" had they not discharged nine patients prior to completion of the protocol (four of which were lost to follow-up). Furthermore, only one patient developed a CXR-detected PTX during the study period; is that sufficient to conclude the three-hour rule can replace the six-hour rule?

This is the second study examining the use of a three-hour CXR to rule out delayed PTX and hemothorax in asymptomatic patients with negative initial CXRs.2 Both of these studies suggest that the three-hour film is as reliable as the six-hour film; however, the study by Kiev and Kerstein and the above-mentioned Kerr et al study (6-hour rule) eliminated patients with precordial and periclavicular wounds. This study does not specifically mention these cases (they state only that patients requiring immediate admission to the operating room or ICU were excluded), and we are left to wonder whether these patients underwent pericardial exploration for precordial wounds or angiography for periclavicular wounds. One question that remains to be answered is how long to observe and how best to manage the several asymptomatic patients in each study with a PTX visible only by CT scan. 

References

1. Kerr TM, et al. Prospective trial of the six hour rule in stab wounds of the chest. Surg Gynecol Obstet 1989; 169:223-225.

2. Kiev J, Kerstein MD. Role of three hour roentgenogram of the chest in penetrating and nonpenetrating injuries of the chest. Surg Gynecol Obstet 1992;175: 249-253.