Chest roentgenography after outpatient thoracentesis

To evaluate the clinical utility of posteroanterior chest roentgenograms after thoracentesis in the outpatient setting.

We undertook a retrospective study of clinical records of outpatient thoracentesis performed between January and December 1996 by the Division of Pulmonary and Critical Care Medicine at Mayo Clinical Rochester.

The medical records of 54 men and 39 women who underwent 123 outpatient thoracentesis were reviewed. Exclusion criteria were the need for pleural biopsy at time of thoracentesis or the need for ultrasound-guided assistance for completion of the procedure. Indications for thoracentesis and postthoracentesis chest roentgenography were analyzed.

Of 123 thoracentesis performed in the outpatient setting during the specified study period, 104 met the inclusion criteria. Of these 104 thoracentesis, 54 (52%) were followed by chest roentgenography. Pneumothorax occurred in only 5 of these 104 procedures (5%), in 5 separate patients. Three of these patients were asymptomatic and did not require therapeutic intervention; the two symptomatic patients required hospitalization and chest tube drainage. Of the two pneumothoraces in patients with symptoms, one was detected on the same day as the thoracentesis, and the other was diagnosed 2 days later. The patients who did not undergo postthoracentesis chest roentgenography had no reported complications. Of the 54 chest roentgenograms, 52 were obtained in asymptomatic patients, with no suspicion of pneumothorax. These x-ray studies led to a total cost of $4,862 and detection of three pneumothoraces that did not require therapy.

Routine performance of chest roentgenography after outpatient thoracentesis can incur substantial cost. A more selective approach to this practice is needed, both to optimize patient care and to manage limited medical resources efficiently. Postthoracentesis chest roentgenograms should be limited to patients with symptoms indicative of thoracentesis-induced pneumothorax.