Original studies of ultrasound-guided thoracentesis concluded a 2% risk of pneumothorax. A recent single center study of 9320 thoracenteses over 12 years all by procedural experts had pneumothorax rate of 0.6%. This same study also demonstrated a very low incidence of both re-expansion pulmonary edema (REPE) at 0.01% and serious bleeding episode at 0.2%.
The investigators noted that the risk factors for pneumothorax included more than one pass through the skin (OR = 5), low body mass index (BMI < 18) (OR = 3), and removal of more than 1500 mL of fluid (OR = 5). If a patient develops persistent chest pain, severe dyspnea, or subjective sensation of increasingly negative intrapleural pressure during aspiration then thoracentesis should be stopped. This study confirms that ultrasound-guided thoracentesis is safe and associated with a very low rate of procedural complications.