A case of inaccurate prognostication after the ARCTIC protocol

Therapeutic hypothermia (ARCTIC, or Advanced Resuscitation Cooling Therapeutics and Intensive Care protocol) is a widely recommended intervention to improve mortality and neurologic outcomes after cardiac arrest. However, neurologic outcomes are difficult to predict soon after cardiac arrest in the setting of hypothermia, as illustrated by this case report. A 60-year-old man had witnessed cardiac arrest at home. He was defibrillated twice, with return of spontaneous circulation, and cooled to 33°C for 24 hours. Neurologic exam on Day 6 revealed limited brainstem reflexes, and the intensive care unit team discussed with the patient's family that his prognosis for neurologic recovery was poor. Palliative care was consulted to participate in a goals-of-care meeting. Just prior to the meeting on Day 7, the patient awoke. He fully recovered and walked out of the hospital on Day 18. Prior to induced hypothermia, indicators of poor outcome included lack of one or more brainstem reflexes (pupillary or corneal reflex), absence of motor response at 72 hours, myoclonus, status epilepticus, electroencephalogram with generalized suppression, and absent bilateral cortical N20 response to somatosensory-evoked potentials. However, several studies have found these indicators to be unreliable after hypothermia. This may be the result of sedatives, which can affect physical examination and electroencephalogram results, and delayed clearance. Because of the unreliability of prognostication tests within the first 72 hours of hypothermic protocols in the setting of sedation, it appears prudent in some cases to delay final prognosis discussions until at least six days postcardiac arrest and after neurologic evaluation is done with patients sedative-free.