Accuracy of Emergency Medicine Residents Using Point-of-Care Ultrasound (POCUS) to Detect Retained Stingray Barbs

Abstract

Background: Stingray envenomation is a common presenting complaint for coastal emergency departments in the United States. Currently, radiograph is the gold standard to evaluate for a retained stingray barb, but ultrasound may be a useful tool to detect retained barbs.

Objective: To determine if emergency medicine residents could use ultrasound to identify stingray barbs embedded in animal tissue models. A secondary objective was to determine if resident experience affected their ability to detect stingray barbs.

Methods: Thirty-two emergency medicine residents participated in the study. After a short didactic session on foreign body identification with ultrasound, they rotated through six simulation stations and were asked to identify whether a stingray barb was present in pig and chicken tissue models. They were given 2 min per model to identify the presence, size, and depth of a stingray barb. Pre- and postexperiment surveys were collected to assess the residents' level of experience and confidence regarding foreign body identification using ultrasound.

Results: Residents accurately identified barbs in chicken drumsticks with a sensitivity of 72.92% (95% confidence interval [CI] 63.89-81.48) and a specificity of 64.58% (95% CI 54.16-74.08), and in pig's feet with a sensitivity of 50.00% (95% CI 39.62-60.38) and specificity of 68.75% (95% CI 58.48-77.82). There was no statistically significant difference regarding accuracy for any outcome measured based on experience or level of training.

Conclusions: The use of point-of-care ultrasound by novice sonographers lacks sensitivity to identify retained stingray barbs in animal models and is not significantly impacted by resident experience with point-of-care ultrasound.

Keywords: barb; foreign body; point-of-care; retained; stingray; ultrasound.