Apnea test for determination of clinical brain death‏

It is recommended that the apnea test be performed as follows:

A. Prerequisites:

Corect Temperature 36.5°C or 97°F
Systolic blood pressure 90 mm Hg
Corrected diabetes insipidus (Positive fluid balance)
Normal PCO2 (Arterial PCO2 of 35-45 mm Hg)
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B. Preoxygenate with 100% O2 for 30 minutes

C. Connect a pulse oximeter and disconnect the ventilator

D. Place a nasal cannula at the level of the carina and deliver 100% O2, 8 L per minute

E. Look closely for respiratory movements (abdominal or chest excursions that produce adequate tidal volumes)

F. Measure PO2, PCO2, and pH after 10 minutes and reconnect the ventilator

G. If respiratory movements are absent and arterial PCO2 is 60 mm Hg (option: 20 mm Hg increase in PCO2 over a baseline normal PCO2), the apnea test result is positive (supports the diagnosis of brain death)
Connect the ventilator if during testing the systolic blood pressure becomes < 90 mm Hg or the pulse oximeter indicates significant desaturation and cardiac arrhythmias are present: immediately draw an arterial blood sample and analyze ABG!

H. If PCO2 is 60 mm Hg or PCO2 increase is > 20 mm Hg over baseline normal PCO2, the apnea test is positive [supports the clinical diagnosis of brain death]
J. If the PCO2 is < 60 mm Hg or PCO2 increase is < 20 mm Hg over baseline normal PCO2, the result is indeterminate and an additional confirmatory test can be considered

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