Abstract 228: Neurological Outcomes of Cardiac Arrest Survivors with Myoclonus Following Resuscitation

Abstract

Objectives: Historically, myoclonus was thought to portend a hopeless prognosis after cardiac arrest (CA). We evaluated the outcomes and characteristics of CA survivors with myoclonus in a large prospective registry. Methods: Retrospective review of the International Cardiac Arrest Registry (INTCAR) Findings: Of 2564 patients entered into INTCAR between 12/2008-12/2011, 466 (18%) had myoclonus, with an average age of 61.8 (SD 15.9) years, 84% OHCA, initial rhythm VT/VF in 47%, asystole in 28%, and PEA in 21%. Mean “no flow” interval was 8.6 (7.2) minutes, “low flow” interval 17 (15.2) minutes, and total time to return of circulation (TTROSC) 25.6 (15.5) minutes. Therapeutic hypothermia (TH) was applied in 444 (95%) patients, and 334 (72%) had EEG monitoring. Good Outcome (GO) with CPC1-2 occurred in 27 patients at ICU discharge, increasing to 43 (9.2%) at hospital discharge. For patients with GO, mean age was 53.6 (15.6), 79% VT/VF, and TTROSC was 18.6 (12.8) minutes. The EEG showed continuous activity with diffuse slowing in 61% of GO patients, and median hospital LOS was 14.5 days [IQR 9-22]. Of 423 myoclonus patients with poor outcome (PO = CPC3-5), life support was withdrawn in 330 (78%); due to neurological futility in 293 (89%), and the EEG (n=306) showed burst suppression in 152 (49.7%), status epilepticus in 102 (33.3%), severe background attenuation in 75 (24.5%) and continuous activity with diffuse slowing in 75 (24.5%). Among PO patients, 49 (11.6%) did not receive or complete TH. Median hospital LOS in this cohort was 5 [IQR3-7] days. Of 293 patients that died of “neurological futility”, 131 (45%) died less than 5 days after CA. Conclusions: Myoclonus after cardiac arrest should not be considered uniformly fatal. Despite early withdrawal or less than fully aggressive life supportive measures in many patients, 9.2% of myoclonus patients in a large registry population had good outcomes.