Describing the learning curve of novices for the diagnosis of paediatric distal forearm fractures using point-of-care ultrasound.

Purpose: The learning curve of nurse practitioners (NPs) to accurately diagnose paediatric distal forearm fractures using point-of-care ultrasound (POCUS) was investigated. Methods: Each NP's learning curve was calculated as cumulative diagnostic accuracy against a number of scans performed. The curve's plateau represented the attainment of competency. Secondary outcomes were the comparisons before and after this cut-off of diagnostic accuracy, classification of diagnostic errors, pain scores, duration and preference. Results: Five NPs performed 201 POCUS studies with diagnostic accuracy plateauing at 90%, providing a 'cut-off' point at scan 15. Accuracy of POCUS scanning before and after the fifteenth scan was 81% (95% CI 70%-89%) and 90% (95% CI 84%-94%), respectively, demonstrating 9% improvement (P = 0.07). There was a 10% reduction in image interpretation errors. After fifteen scans, POCUS became faster (mean difference (MD) 2.6 min [95% CI 2.0-3.3], P < 0.001), less painful (MD 0.61 points FPSR scale [95% CI 0.04-1.18], P = 0.04) and more preferred by NPs (63% vs 77%, P = 0.03). Discussion: The learning curve of POCUS-novice NPs independently scanning paediatric distal forearm injuries plateaued with mean diagnostic accuracy of 90% after 15 scans, suggesting competency was attained at this cut-off, supported by higher accuracy, being faster, less painful and more preferred by NPs. Future training packages in forearm POCUS should further address image interpretation and provide ongoing expert feedback. Conclusions: The findings from this study suggest that competency in paediatric distal forearm POCUS can be attained by novices after a short training course and approximately 15 scans.