This document discusses anoxic brain injury caused by cardiac arrest. It defines anoxic brain injury as occurring when the brain does not receive enough oxygen, usually after the heart stops pumping. It outlines that the brain can become irreversibly damaged after only 4 minutes without blood supply. The document describes how clinicians use tests such as CT scans and those measuring brain electrical activity to determine the severity of brain damage following cardiac arrest. It also explains that the prognosis for most patients is poor, with predictors being older age, multiple pre-existing diseases, a long duration of cardiac arrest, and an unwitnessed cardiac arrest.

1. Anoxic brain injury and neurological braindeath
: Information for patients and families
Vancouver General Hospital Intensive Care Unit
Myp Sekhon MD
Clinical Instructor, Staff Intensivist
Vancouver General Hospital
Division of Critical Care Medicine
University of British Columbia

2. Outline
Definition
Etiologies
Imaging
Management
Prognosis
Braindeath
Definition
Anoxic brain injury occurs when the brain does not receive
enough oxygen to stay alive. Most commonly, this scenario
happens after the heart stops pumping (a “cardiac arrest”).

3. Outline
Definition
Etiologies
Imaging
Management
Prognosis
Braindeath
What causes the heart to stop
beating?
An abnormal rhythm (electrical abnormality) of the heart
can stop it from beating
Depending on the type of electrical abnormality, the
problem might be inside the heart or another problem in the
body causing the heart to stop
An investigation will be conducted to find the underlying
problem, if possible

4. Outline
Definition
Etiologies
Imaging
Management
Prognosis
Braindeath
What happens to the brain after a
cardiac arrest?
The brain is the most important organ in the body
Unfortunately, the brain does not have a storage of energy
If it stops receiving blood flow and oxygen from the heart /
lungs, it will start to become irreversibly damaged after
only
4 minutes without blood supply
If blood flow (delivery of oxygen) is not restored, the brain
will start to die and it can become very swollen

5. Outline
Definition
Etiologies
Imaging
Management
Prognosis
Braindeath
How do we know the brain is
damaged?
We use multiple methods of assessment to determine the
severity of brain injury after a cardiac arrest:
•Clinical examination
•History – initial abnormal rhythm, duration without
blood supply, if the patient received immediate CPR
etc.
•CT scans
•Tests measuring the electrical activity of the brain

6. If blood is restored to the brain (heart re-started) then our
focus is optimize the delivery of oxygen to the brain
This is achieved by:
•Maintain blood pressure with medications to allow the
heart to pump blood to the brain
•We control the temperature of the body – this is done
to prevent a fever which make the brain use more
oxygen and potentially cause more injury
•We used sedation medications to “rest” the brain and
allow time for healing. This is usually for 24-48 hours.
Outline
Definition
Etiologies
Imaging
Management
Prognosis
Braindeath
How do we treat patients with brain
damage after a cardiac arrest?

7. Outline
Definition
Etiologies
Imaging
Management
Prognosis
Braindeath
Prognosis?
The prognosis of most patients is poor (~50-70%).
Predictors of poor outcome include:
•Older age
•Multiple previous diseases (heart disease, diabetes,
kidney disease, lung disease etc)
•Long duration of cardiac arrest
•Unwitnessed cardiac arrest
•Poor clinical examination (we will help with this)