When a loved one suffers a cardiac arrest and ends up in a coma (called “anoxic-ischemia encephalopathy), what if any, are the predictors of a good outcome? How much time should elapse before the decision is made to withdraw life support? What are the chances of remaining in a persistent, vegetative state with no evidence of conscious awareness? What are the chances of being severely disabled and totally dependent on a family member for sustaining life?

If consciousness is to be gained, it is best to wait for 3 days before any decisions are made about withdrawing life support in a comatose patient. “This is because motor responses…will have returned in the vast majority of patients if consciousness is to be regained, at least for patients who are not treated with hypothermia,” writes the author, G. Bryan Young, MD, of a paper recently published in the New England Journal of Medicine (NEJM).

Prospective studies have shown that the following clinical signs, if absent after 3 days, (or after 6 days with one clinical sign mentioned below), were likely to be very reliable predictors of a poor outcome. The first 5 markers are controlled by the brain stem, the primitive part of the brain. Absence of function to this area, which can tolerate less oxygen than other areas of the brain, are an indication that the areas of the brain noted for higher function are severely damaged.

1. Pupils fail to react/respond to light being shone in them.
2. No muscle movement to painful stimuli except for a reflexive, rigid posturing of the arms and legs that is seen in comatose patients (2 out of 14 patients showed some awareness on day 6 who had undergone hypothermia therapy, hence the exception mentioned above).
3. Lack of corneal reflex when a cotton swab is brushed against the eye.
4. Absence of eye movements when ice water is flushed into the ear canal.
5. Synchronous twitching of the limbs, trunk or facial muscles.
6. Lack of nerve response to stimulation of the median nerve of the wrist which is connected to a specific region of the brain, called the primary somatosensory cortex.

CTs and MRIs are often normal right after a cardiac arrest and are taken when the patient first arrives in the hospital and again, generally after 3 dayss. However, there are no established criteria using these tools to determine brain functioning.

If there continues to be an absence of brainstem function after 3 days, prognosis for any recovery beyond a persistent, vegetative state or severe, total disability, is poor.

Overall, it behooves all of us to ensure that we have talked to our loved ones about our wishes to be kept alvie in the event of a cardiac arrest and subsequent coma. Families should not make these decisions is not during a period of crisis.

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