Pneumothorax and the value of chest radiography after ultrasound-guided thoracocentesis

Purpose: To determine the incidence, the operator's experience, and other variables that may influence the development of pneumothorax or re-expansion edema after ultrasound (US)-guided thoracocentesis. Material and Methods: The medical records of 264 procedures in 212 patients who had undergone US-guided thoracocentesis in our radiology department or intensive care unit during the period 1996-2001 were retrospectively reviewed. Results: Post-thoracocentesis pneumothorax occurred in 11 cases, the incidence being 4.2% (11/264). None of the pneumothoraces occurred in the 10 mechanically ventilated patients. All but one patient with pneumothorax were asymptomatic or had only minor symptoms. Chest tube drainage was needed in one patient with a large pneumothorax. No re-expansion edema was recorded, although 1500 ml or more pleural fluid was aspirated in 29 patients. The operator's experience had no effect on the complication rate. Needle size was the only significant variable that contributed to the pneumothorax rate. Conclusion: US-guided thoracocentesis can be done equally as safely by residents as by senior radiologists. The safety and feasibility of the method are evident among mechanically ventilated intensive care patients. Our results do not support the routine use of post-thoracocentesis chest radiography.