Point-of-Care Ultrasound for Emergency Pericardiocentesis: A Multidimensional CUSUM Analysis of the Learning Curve

Background Emergency point-of-care ultrasound-guided percutaneous pericardial catheter drainage (US-GPPCD) is a critical intervention for cardiac tamponade; however, its learning curve for novice operators without prior independent experience in emergency settings remains poorly defined. This study investigated the learning curve, procedural outcomes, and complications of this procedure performed by a single novice operator. Methods A total of 33 consecutive patients who underwent US-GPPCD performed by a single novice operator without prior independent experience in US-GPPCD between October 2024 and December 2025 were enrolled. Demographic and clinical characteristics, procedure time, needle insertion site localization time, operator confidence score, operator position, and complications were collected. Three separate cumulative sum (CUSUM) learning curves were constructed using procedure time, localization time, and operator confidence score as outcome measures, respectively, enabling a multidimensional analysis of the learning curve. Results CUSUM analysis divided the learning curve into phase 1 (cases 1–14) and phase 2 (cases 15–33). Procedure time (median 12.7 min) and needle insertion site localization time (median 3.9 min) in phase 1 were significantly longer than those in phase 2 (7.9 min and 2.0 min, respectively), while operator confidence score was significantly lower than that in phase 2 (5.0 vs 9.0), all with statistical significance (all P < 0.01). Although the complication rate in phase 1 (28.6%) was higher than that in phase 2 (5.3%), the difference was not statistically significant ( P = 0.14). In addition, after the operator changed the position from the patient's right side to the left side, procedure time was significantly shortened ( P < 0.01). Conclusion US-GPPCD is a safe and effective emergency intervention for novice residents. Procedural proficiency, defined by operative efficiency, is attained after approximately 14 procedures, while operator confidence consolidates shortly thereafter. Optimizing operator positioning further enhances procedural efficiency. These findings provide a quantitative framework for developing competency-based, phased training programs and for refining clinical protocols for US-GPPCD.