A 72 year-old woman with CAD c/b STEMI s/p 3vCABG, ICM/HFrEF (LVEF 40%), HTN, and COPD (home 2L NC) was brought in to the ED by EMS after sustaining a cardiac arrest.
The patient was at home and suddenly became unresponsive. Her husband, a former nurse, witnessed this and immediately tried to wake her. She did not respond. He checked for a pulse, and not finding one, he promptly began chest compressions. EMS arrived and was able to place an automated chest compression device. She was intubated in the field. ROSC was obtained after about 20 minutes, after several cycles of chest compressions and doses of epinephrine and amiodarone. Her rhythm at the pulse checks was v-fib. She still had a pulse by the time she arrived to the ED, though she was completely unresponsive.
She undergoes whole-body CT scanning, without any revealing findings. Notably, her non-contrast head CT was unremarkable. Cardiology is consulted, but recommends against left heart catheterization. She is admitted to the medical ICU thereafter. The primary team consults you for post-arrest recommendations and neuroprognostication. On your exam, during which the patient is on propofol gtt and fentanyl gtt, you identify non-reactive pupils, 4mm in diameter each, absent corneal reflex, intact cough reflex, and triple flexion response to noxious stimuli in the extremities.
One of the major questions you might be asked is whether the team should pursue therapeutic hypothermia. This is a pretty controversial subject, and the verdict still isn't out. You've heard of the TTM and TTM2 trials, which found no difference in mortality or functional outcomes at 6 months in comparing 33C vs. 36C and 33C vs. 37.8C, respectively, for patients with out-of-hospital cardiac arrests (OHCA). There are a couple of caveats to this, such as the high rate of bystander CPR and the fact that standardized aggressive care was pursued overall, unlike in the past when perceived futility was even much higher. Specifically, neuroprognostication was standardized and wasn't made until at 96hrs after randomization or later. The most recent 2021 AHA and ILCOR CoSTR guidelines recommend deliberate temperature management, though don't specify any particular targets. Notably, it's recognized that a wide range of temperatures is safe, but there's still insufficient evidence to identify which patients could benefit from a particular temperature range. Considerations such as coagulopathy and need for interventions do play into whether the lower range is pursued.
In terms of neuroprognostication, it's definitely way too early. We must wait until 48-72 hours after ROSC. It's not surprising to find some absent brainstem reflexes this early in her course; this is meaningless for her prognosis. (If persistent at 72 hours, that's a different story, of course.) In the meanwhile, we can ask them to minimize the use of sedation as much as possible. If they opt to cool the patient, then they'll need to be generous with the sedation, but once they're rewarmed, they should be off sedation unless there's a good reason. They can still target the usual physiologic parameters, aiming for normocapnia, normoxia, euglycemia, and normonatremia. There's no evidence-based specific range for each of these. (In the ICU, we generally want 140-180mg/dL, but that's not post-arrest-specific.)
Another recommendation you make is to start continuous EEG. These patients are at high risk of having non-convulsive seizures, and certain electrographic features throughout their course may help you in your prognostication.
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