Skin Sympathetic Nerve Activity as a Biomarker for Neurological Recovery during Therapeutic Hypothermia for Cardiac Arrest

Abstract Background Targeted temperature management (TTM) improves neurologic outcome after cardiac arrest. However, better neurological prognostication is needed. Objective To test the hypothesis that noninvasive recording of skin sympathetic nerve activity (SKNA) and its association to heart rate (HR) during TTM may serve as a biomarker of neurologic status. Methods SKNA recordings were analyzed from 29 patients undergoing TTM. Patients were grouped based on the Clinical Performance Category (CPC) score into Group 1 (CPC of 1-2) representing a good neurologic outcome and Group 2 (CPC of 3-5) representing a poor neurologic outcome. Results Out of all study participants, 18 of 29 (62%) were deemed to have poor neurologic outcome. At all timepoints, low average SKNA (aSKNA) was associated with poor neurologic outcome (Odds Ratio (OR) = 22.69, p=0.002) and remained significant (p=0.03) even when adjusting for presenting clinical factors. The changes in aSKNA and HR during warming in Group 1 were significantly correlated (ρ=0.49, p Conclusions Neurological recovery was retrospectively associated with SKNA. Patients undergoing TTM who did not achieve neurological recovery were associated with low SKNA and lacked a significant correlation between SKNA and HR. These preliminary results indicate that SKNA may potentially be a useful biomarker to predict neurological status in patients undergoing TTM.