Limited utility of chest radiograph after thoracentesis

Study objective: To assess the utility of chest radiograph (CXR) immediately after routine thoracentesis. Design: Prospective cohort study. Setting: Multispecialty clinic/teaching hospital, Participants: till outpatients and inpatients undergoing thoracentesis ill the procedure area from October 1995 to January 1998, Measurements: Immediately after thoracentesis, the physician completed a questionnaire assessing the likelihood of a complication, CXRs were obtained at physician discretion. Patient demographics, indications for thoracentesis, use of ultrasound guidance, level of training, radiographic interpretation, and eventual patient outcome were recorded. Results: Two hundred eighteen patients were enrolled for a total of 278 thoracenteses. Two hundred fifty-one procedures pel,formed on 199 patients could be prospectively evaluated. A complication was suspected in 30 procedures; immediate CXR confirmed such ill 9 (30%). There were 221 procedures with Ilo clinical suspicion or indication of a complication. Ninety CXRs were obtained immediately after the procedure; the remaining 131 procedures had no CXR. The complication rates were 3.3% and 2.3%, respectively, for these groups. Four postthoracentesis radiographs demonstrated additional findings regardless of the indication for the radiograph, Conclusions: ill the absence of a clinical indication of a complication, chest radiography is not indicated immediately after routine thoracentesis. Aspiration of air strongly correlates with the occurrence of pneumothorax, whereas pain, hypotension, and dry tap do not. Use of a vacuum bottle to withdraw fluid obscures the appreciation of this finding and was identified as a risk factor for subsequent pneumothorax. Additional radiographic findings are rarely detected and may not contribute to clinical management.