Pneumothorax Following Transbronchial Biopsy: DISCUSSION
Routine chest roentgenograms following TBB rarely demonstrate a pneumothorax in patients without both chest pain and fluoroscopic findings of a pneumothorax. In no instance did any of the 305 routine chest roentgenograms obtained after TBB reveal an unsuspected pneumothorax. The two pneumothoraces which did occur were immediately diagnosed in the bronchoscopy suite by symptoms and the appearance of fluoroscopic findings of lung collapse.
The combination of chest pain and abnormal fluoroscopy appears to be an indicator of a pneumothorax after TBB. No false negative results occurred in our series using the combination of chest pain and abnormal fluoroscopy as a test for pneumothorax after TBB. We do not know how many of the 303 patients without a pneumothorax had chest pain and abnormal fluoroscopy. However, our estimate of the false positive rate is low, since in a subgroup of 42 patients without a pneumothorax, only one patient had both chest pain and fluoroscopic findings suggestive of lung collapse. As there were only two patients with a pneumothorax, estimates of false negative and false positive rates of these clinical indicators of pneumothorax lack precision.
Our study is the first investigation reviewing a large, consecutive series in which all patients undergoing TBB had a routine postbiopsy chest roentgenogram. In an abstract, Milam et al reported 100 consecutive bronchoscopies. The only recognized pneumothorax in this series occurred in a patient with both chest pain and fluoroscopic findings of lung collapse. Only 80 of the 100 patients had a postprocedure chest roentgenogram, and only 56 patients had TBB. Ahmad et al have shown the safety of obtaining chest x-ray films after TBB only if a complication is suspected during the procedure. Of 148 patients undergoing uncomplicated TBB, only one developed a clinically apparent pneumothorax. Since only symptomatic patients had chest x-ray films, the incidence of subclinical pneumothorax in this series is not known.
Our low rate of detecting unsuspected pneumothoraces with routine chest roentgenograms may not apply to all patients. Though the post-TBB pneumothorax incidence reported here (.7 percent) is within the previously published range, we could have seen a greater number of unsuspected pneumothoraces if the incidence of pneumothorax had been higher. Patients at increased risk for developing a postbiopsy pneumothorax, such as those with bullous disease or receiving positive pressure ventilation, may have a greater number of unsuspected pneumothoraces after TBB. The incidence of unsuspected pneumothorax may also be higher in patients undergoing TBB without fluoroscopy or in patients unable to acknowledge chest pain. Finally, although an unsuspected pneumothorax may be rare, it may also be fatal, especially in patients with underlying lung disease.
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This study is retrospective and contains few patients with a pneumothorax. However, at the University of Virginia, routine chest roentgenograms failed to demonstrate a single unsuspected pneumothorax among all patients undergoing TBB over nearly six years. Given this low incidence of unsuspected pneumothorax, we conclude that routine chest roentgenograms have a low diagnostic yield and may not be necessary in all patients after fluoroscopically-guided TBB.
