Understanding Neurological Prognostication

Heartbeat is back but my loved one is still not waking up… When will they?

Despite successful immediate care, sometimes your loved one might not wake up immediately or even after a few days. Doctors will evaluate for awakening and brain recovery every day with the goal of knowing whether they will wake up or not, and if they do, how much meaningful neurological activity they will have (also referred to as “neurological outcome”).

Waking up

Understanding the awakening from a coma and the neurological outcome thereafter involves multiple steps:

• • The first step is to turn off sedation temporarily in the morning and ask your loved one to follow simple commands. Usually, doctors will ask things such as “Open your eyes,” “Show me 2 fingers,” “Give me a thumbs up,” or “Wiggle your toes.” This will give them an idea of the status of your loved one’s awareness.

• • If there is no command following, clinicians may try inflicting a painful stimulus such as pinching the skin or pressing on the nail bed. Don’t worry – though it may look very painful, the pain threshold for someone under these circumstances is different from that of an awake and alert person. Clinicians do this to see if the person has their sensation intact and if they can move their extremities normally. Sometimes there may be abnormal movements present that can be non-purposeful. These movements do not necessarily mean that the person is intentionally moving their arms and legs, and they do not give any insight into their awareness or muscle strength.
  • Doctors will check other things such as the pupil’s response to light and your loved one’s cough or gag reflex when suctioned through the breathing tube.

Next steps

If your loved one has not awakened after a few days from the time they had their heart beating again or cooling treatment completed, the clinicians may proceed with specific tests to evaluate for brain injury resulting from the lack of oxygen to the brain during cardiac arrest. They may also call in a neurologist (a brain specialist) to assist. Some of the tests that doctors may order are computed tomography of the brain (also called “CAT scan” or “brain CT”), an electroencephalogram (EEG) to look at the electrical activity of the brain, a blood test to check for chemicals released after brain injury, or a brain magnetic resonance imaging (MRI) at some centers to get a closer look into the structures of the brain. Each test will provide a different aspect to understand the level of brain damage and your loved one’s chance of recovery. Each test contributes to a part of the puzzle. Not all tests may be needed or done at all centers and the clinicians along with a neurologist will determine which ones are needed and how to read them to make a recommendation. 

Based on the tests mentioned above along with the neurological exam, doctors will try their best to guide you into your loved one’s neurological prognosis and what will be the next destination for them. Sometimes to help you understand their recommendation, they will paint a picture of your loved one’s dependency on you or other family members after discharge from the hospital for activities of daily living (for example bathing, eating, toileting). This can be a very difficult time for families, as the prognosis can sometimes be uncertain if tests are inconclusive, but the person may still not be showing clear signs of improvement in brain function. Family meetings with members of the different medical teams are held to discuss your loved one’s and your wishes regarding further steps in their care.

Assessing outcomes

If at any point in time, your loved one’s neurological status worsens to the point that clinicians become concerned about brain death, additional steps have to be taken. Brain death (also known as brain stem death) is when a person on an artificial life support machine no longer has any brain function. This means they will not regain consciousness or be able to breathe without support. A person who is brain dead is legally confirmed as dead in almost all states in the United States. Brain death is irreversible. Doctors will likely involve neurologists at this point, and formal brain death testing will be performed. This includes the neurological exam to show an absence of all “brain stem reflexes” such as pupils, cough, and gag, along with a breathing test to make sure there are no spontaneous breaths. This is called the “apnea test.” Occasionally, these tests can’t be performed due to medical reasons, and then advanced brain imaging has to be performed to confirm the diagnosis of brain death.

Sources

Examination of the Unconscious Patient: https://litfl.com/examination-of-the-unconscious-patient/

Guidelines for Neuroprognostication in Comatose Adult Survivors of Cardiac Arrest: https://link.springer.com/article/10.1007/s12028-023-01688-3

Thank you to our contributors

Samantha Fernandez & Sachin Agarwal