Ventilator autocycling and delayed recognition of brain death

Improvements in technology play an important role in caring for critically ill patients. One example is the advance in ventilator design to facilitate triggering of mechanical breaths. Minimal changes in circuit flow unrelated to respiratory effort can trigger a ventilator breath and may mislead caregivers in recognizing brain death.

We observed patients with devastating brain injuries in a mixed medical/surgical intensive care unit (ICU) with a high clinical suspicion for brain death including the absence of cranial nerve function with apparent spontaneous breathing during patient-triggered modes of mechanical ventilation. Further clinical observation for spontaneous respirations was assessed upon removal of ventilatory support.

Nine patients with brain injury due to multiple etiologies were identified and demonstrated no spontaneous respirations when formally assessed for apnea. Length of time between brain death and its recognition could not be determined.

When brain-dead patients who are suitable organ donors are mistakenly identified as having cerebral activity, the diagnosis of brain death is delayed. This delay impacts resource utilization, impedes recovery and function of organs for donation, and adversely affects donor families, potential recipients of organs, and patient donors who may have testing and treatment that cannot be beneficial. Patients with catastrophic brain injury and absent cranial nerve function should undergo immediate formal apnea testing.