Determining Brain Death: 2/3

I’m continuing with a series on how brain death is determined. All hospitals likely have a policy in place with strict guidelines on how brain death is determined. Check last post for the beginning stages.

Now, we’ll move onto actual testing.

Can the patient breathe on their own? This is a relatively simple test. It’s called apnea testing. The ventilator is turned off and we see what the patient will do. Naturally, when we stop breathing, carbon dioxide will build up in the blood stream. Your body has receptors that monitor the level of CO2 and it will initiate a breath when the levels rise.

Here is the procedure for performing an apnea test.

1. The patient will be on an ECG and pulse ox monitor.

2. Give the patient 100% oxygen for five minutes.

3. After five minutes, disconnect the patient from the vent, but give oxygen via T-piece. The breathing tube will still be in place. At this point, the patient is off the vent and no longer being assisted but will have needed oxygen if they do initiate a breath.

4. Watch the patient for breathing. If any attempt is made to breathe, it is inconsistent with brain death and the test is stopped and the patient is placed back on the ventilator.

5. If the patient has any cardiac arrhythmias, low blood pressure or oxygen level that falls to less than 80% (normal level is 90-100%) then the test is discontinued. These finding will lead more to a conclusion that brain death has occurred.

6. If the carbon dioxide level increases above 60 (normal level is 35-45)—the apnea test is consistent with brain death. The brain is very sensitive to rising levels of carbon dioxide and the absence of a response is consistent with brain death.
Next post, we’ll talk about brain perfusion studies.

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