Can Emergency Physicians Identify Frozen Tissue on Ultrasound? Implications for Frostbite Management

IntroductionFrostbite injuries cause disfigurement and loss of functionality. The role of early imaging in management remains unclear because most modalities require infrastructure that prevents field application. Providers use point-of-care ultrasound to assess a range of soft tissue and musculoskeletal pathologies. The primary objective of this study is to determine the accuracy with which emergency physicians can identify frozen tissue on ultrasound.MethodsThree emergency medicine physicians evaluated whether porcine tissue was frozen or unfrozen by viewing standardized ultrasound clips. The team recorded clips of tissue thawing in a water bath from -10 to +10°C using a handheld ultrasound device. Each physician independently reviewed randomized clips and recorded their assessments. A 2 × 2 table was used to calculate the pooled sensitivity and specificity.ResultsEmergency medicine physicians reviewed 75 clips. They achieved a pooled sensitivity of 76% (95% CI 0.60-0.87) and a specificity of 87% (95% CI 0.68-0.96) for detecting frozen tissue compared with the tissue thermometer as the standard. Their results showed an overall accuracy of 80% (95% CI 0.69-0.88).ConclusionsIn this pilot study, emergency medicine physicians with advanced point-of-care ultrasound training identified frozen tissue on ultrasound 80% of the time. Future research should explore the sonographic features of frozen tissue in cases of frostbite and the test characteristics for sonographers with varying skill levels.