Apnea testing in brain death.

A standardized protocol was followed in 33 apneic oxygenation tests on 20 patients suspected of being brain dead. Spontaneous respiratory movements developed in just one patient; this patient was the only one who did not show electrocerebral silence on electroencephalography. Significant hypoxemia, hypotension, or cardiac arrhythmias were not encountered despite lung disease in 14 of our 20 patients. The apnea test protocol employed proved to be safe and sensitive. With a starting partial arterial carbon dioxide pressure greater than or equal to 36 mm Hg and a disconnection time from the ventilator of ten minutes in a normothermic patient (greater than or equal to 36.1 degrees C [greater than or equal to 97 degrees F]), the pressure threshold of 60 mm Hg should be reached in all patients.