The Characteristics and the Predicting Factors of Hypoxic Myoclonus in the Post Cardiac Arrest Patient

ABSTRACT

PURPOSE: Hypoxic myoclonus is usually a sign of favorable prognosis in cardiac arrest survivors. No single specific factor has yet been consistently predictive of myoclonus or status epilepticus accompanying post-cardiac arrest status. The aim of this study was to investigate characteristics and the predicting factors of myoclonus in patients who recovered from cardiac arrest. METHODS: A single center, retrospective study was conducted from January 2011 to December 2013. A total of 174 patients who were over 18 years of age and who survived longer than 72 hours after cardiac arrest were enrolled. Patients were divided into two groups according to the development of myoclonus. Individual characteristics, information related to cardiac arrest and post-cardiac arrest status, method of evaluation and treatment, and the Cerebral Performance Category (CPC) score were collected. RESULTS: Of all patients, 42 were assigned to the myoclonus group and 132 to the non-myoclonic group. Forty patients (95.2%) in the myoclonic group presented with generalized myoclonus. Asphyxia, as a presumed cause of arrest, was a statistically significant variable of myoclonus development after cardiac arrest (p=0.048). Initial arrest rhythm, laboratory test, and therapeutic hypothermia were not associated with development of myoclonus. The myoclonic group showed a significant tendency to increase the rate of poor neurologic outcome (CPC 3 to 5) compared to the non-myoclonic group (p<0.00). CONCLUSION: Asphyxia as a cause of arrest may be the single early predictor for development of hypoxic myoclonus in post-cardiac arrest patients.