Abstract Body: Introduction: Previous work has associated frailty with mortality and neurologic outcomes in patients resuscitated from cardiac arrest. The Clinical Frailty Scale (CFS) – a 9-point ordinal scale with higher values indicating a higher degree of frailty – is the most used measure in critically ill patients, however there is no established gold-standard. Temporal muscle thickness (TMT) is a measure of sarcopenia, which represents a specific physical frailty phenotype.

Aim: We assessed the correlation between TMT, measured on head computed tomography (CT), and the CFS in patients resuscitated from cardiac arrest.

Hypothesis: TMT negatively correlates with pre-arrest CFS.

Methods: We enrolled adult patients who were resuscitated from cardiac arrest and had a head CT obtained within 48 hours of collapse at our regional academic facility. Patient characteristics were recorded in our prospective registry. Study investigators prospectively obtained pre-arrest CFS through a patient or surrogate interview. Blinded study investigators reviewed head CTs and measured TMT bilaterally at 5mm above the superior orbital rim, adjacent to the Sylvian fissure. We then averaged the two measurements within each patient. We summarized patient demographics and arrest characteristics with descriptive statistics. We calculated Spearman rank-order correlation to assess the relationship between average TMT and CFS.

Results: Of 20 included subjects, mean age was 57 (SD 13), 6 (30%) were female, 17 (85%) were out-of-hospital arrests, 6 (32%) had an initial shockable rhythm, and median Charlson Comorbidity Index was 2 (IQR 0-3). Mean TMT in our cohort was 6.7 millimeters (SD 2.6) and median CFS was 3 (IQR 2-6). There was a negative, moderate correlation between average TMT and CFS; r(18) = -0.50, p = 0.02.

Conclusions: We found that TMT exhibits a moderate negative correlation with the CFS, providing face validity that TMT may be a tool to measure frailty. Measuring TMT in patients with early head CTs after resuscitation from cardiac arrest may allow for characterization of pre-arrest frailty.