Our series of thoracenteses had a very low complication rate. Current clinical guidelines and practice patterns may not reflect evidence-based best practices.

Residents randomized to an SBML intervention performed thoracenteses with low rates of clinically meaningful complications. Rigorous education represents a successful quality improvement strategy.

Internal medicine (IM) residents and hospitalist physicians commonly perform thoracenteses. National data show that thoracenteses are also frequently referred to other services such as interventional radiology (IR), increasing healthcare costs. Simulation-based mastery learning (SBML) is an effective method to boost physicians' procedural skills and self-confidence. This study aimed to (1) assess the effect of SBML on IM residents' simulated thoracentesis skills and (2) compare thoracentesis referral patterns, selfconfidence, and reasons for referral between traditionally trained residents (non-SBML-trained), SBML-trained residents, and hospitalist physicians. A random sample of 112 IM residents at an academic medical center completed thoracentesis SBML from December 2012 to May 2015. We surveyed physicians caring for hospitalized patients with thoracenteses during the same time period and compared referral patterns, self-confidence, and reasons for referral. SBML-trained resident thoracentesis skills improved from a median of 57.6% (interquartile range [IQR] 43.3-76.9) at pretest to 96.2% (IQR 96.2-100.0) at post-test (P < 0.001). Surveys demonstrated that traditionally trained residents were more likely to refer to IR and cited lower confidence as reasons. SBML-trained residents were more likely to perform bedside thoracenteses. Hospitalist physicians were most likely to refer to pulmonary medicine and cited lack of time to perform the procedure as the main reason. SBMLtrained residents were most confident about their thoracentesis skills, despite hospitalist physicians having more experience. This study identifies confidence and time as reasons physicians refer thoracenteses rather than perform them at the bedside. Thoracentesis SBML boosts skills and promotes bedside procedures that are safe and less expensive than referrals. Internal medicine (IM) residents and hospitalist physicians commonly conduct bedside thoracenteses for both diagnostic and therapeutic purposes. 1 The American Board of Internal Medicine only requires that certification candidates understand the indications, complications, and management of thoracenteses. 2 A disconnect between clinical practice patterns and board requirements may increase patient risk because poorly trained physicians are more likely to cause complications. 3 National practice patterns show that many thoracenteses are referred to interventional radiology (IR). 4 However, research links performance of bedside procedures to reduced hospital length of stay and lower costs, without increasing risk of complications. 1,5,6 Simulation-based education offers a controlled environment where trainees improve procedural knowledge and skills without patient harm. 7 Simulationbased mastery learning (SBML) is a rigorous form of competency-based education that improves clinical skills and reduces iatrogenic complications and healthcare costs. 5,6,8 SBML also is an effective method to boost thoracentesis skills among IM residents. 9 However, there are no data to show that thoracentesi...