360 Predictive Value of Clinical Assessment of Severe Frostbite Injury - Preliminary Outcomes from a Prospective Observational Study

Abstract Introduction Clinical assessment of frostbite is the first line of determining the degree of injury and often the only tool available in small rural centers. This can dictate transfers, treatments, and ultimately patient outcomes. The aim of this study was to examine the predictive value of clinical assessment following severe frostbite injury. Methods Patients admitted for severe frostbite (n = 21) were enrolled in our prospective observational study. They were clinically evaluated on arrival to the hospital, day 3 of hospitalization, and day of discharge. Clinical assessments were then compared to Tc-99 bone scans on admission (n = 20), follow up bone scans after lytic therapy (n = 13), and to final amputation level (n = 20). Clinicians used the Hennepin frostbite score to document level of injury and outcomes. Results Severe frostbite injury impacted those typically suffering these injuries in an urban environment; our patients were predominantly male (86%) and often suffer from mental illness, chemical abuse, or housing insecurity (81%). Clinical assessment showed non-significant mean differences on admission, day 3, and discharge when compared to admission Tc-99 bone scan. The day 3 clinical assessment showed significantly more tissue at risk than the follow up bone scan after lytic therapy (z= -2.2, p=0.03). Significant differences were also seen between final amputation level and the clinical assessments at all time points. Additionally, Bland-Altman plots demonstrated significant differences in the variances between clinical assessment and amputation at all timepoints assessed. No significant correlations were found between amputation level and clinical assessment on admission (r=-0.08, p=0.729), day 3 (r=0.18, p=0.459), or at discharge (r=0.26, p=0.26). Conclusions This preliminary data indicates there is little predictive value in the clinical assessment of severe frostbite injury when evaluating for future amputation. Longer-term, multi-institutional collaborative studies are needed to fully evaluate the potential utility of clinical assessments in patients with frostbite injury. Applicability of Research to Practice Our preliminary data demonstrate no predictive value in clinical assessment of severe frostbite injury. Rural centers often rely on clinical assessment alone that may be inadequate when assessing the need for transfer to another facility or counseling patients regarding treatment options and potential outcomes.