apnea test

Indications

• determination of brain death in a patient with clinical findings* consistent with brain death

* coma; absence of motor response, pupillary response, corneal reflex, jaw jerk, gag reflex, oculovestibular reflex, reaction to craniofacial pain, cough with tracheal suctioning, sucking reflex

Clinical significance

• a positive test confirms brain death
• no further testing is indicated

Procedure

• initiated when the arterial pCO2 is between 40-60 mm Hg, the patient is normothermic, & has received no sedative
• the patient is disconnected from the ventilator to obtain a baseline pCO2 value
• during this time, the patient may receive supplemental oxygen
• arterial blood gas measurements are repeated at 1 minute, 5 minutes & up to 8 minutes while spontaneous respirations are observed
• the apnea test is positive if the pCO2 increases by > 20 mm Hg in the absence of respirations

More general terms

• clinical procedure

Additional terms

• apnea
• brain death