Post-Hypoxic Myoclonus Status following Out-of-Hospital Cardiac Arrest-Does It still Predict a Poor Outcome? A Retrospective Study.

In patients with out-of-hospital cardiac arrest (OHCA), the initial prehospital treatment and transfer of patients directly to intervention clinics-bypassing smaller hospitals-have improved outcomes in recent years. Despite the improved treatment strategies, some patients develop myoclonic status following OHCA, and this phenomenon is usually considered an indicator of poor outcome. With this study, we wanted to challenge this perception. The regional prehospital database in Odense in the Region of Southern Denmark was searched for patients with OHCA from the period of 2011-2016. All 900 patients presenting with a diagnosis of OHCA were included in the study. Patients surviving to the hospital and presenting with myoclonic status were followed for up to one year. Only 2 out of 38 patients with myoclonic status and status epilepticus verified by an EEG survived more than one year. Eleven out of 36 patients with myoclonic status but without status epilepticus survived for more than one year. We found no evidence that myoclonic status is an unmistakable sign of poor outcome when not associated with EEG-verified status epilepticus. The conclusion for clinicians involved in post-resuscitation care is that myoclonic status is uncomfortable to witness but does not necessarily indicate that further treatment is futile.