What explains a patient with brain death (Brain Death) and brainstem involvement, yet still triggering respiratory movements?

From the Guidelines

In a patient with brain death and brainstem involvement who still triggers respiratory movements, these movements are most likely spinal automatisms, also known as Lazarus sign, which are reflexive and do not indicate true breathing or contradict the diagnosis of brain death. The diagnosis of brain death, as outlined in the guidelines for the determination of brain death in infants and children 1, relies on the absence of neurologic function with a known irreversible cause of coma, and the presence of spinal automatisms does not affect this diagnosis. According to the guidelines, the determination of brain death should be based on a clinical diagnosis that includes the absence of neurologic function and apnea, and the presence of spinal automatisms does not indicate apnea reversal 1.

The guidelines also emphasize the importance of apnea testing in the diagnosis of brain death, which is performed to verify the absence of true respiratory drive 1. The persistence of spinal automatisms during apnea testing does not indicate that the patient is not dead, as these movements are not coordinated respiratory efforts and do not require intact brainstem respiratory centers.

It is essential to note that the diagnosis of brain death should be made by experienced clinicians who are familiar with the guidelines and have specific training in neurocritical care 1. The guidelines also recommend that the diagnosis of brain death should be declared after confirmation and completion of the second clinical examination and apnea test, and that all aspects of the clinical examination, including the apnea test, should be appropriately documented 1.

In the context of brain death diagnosis, it is crucial to distinguish between spinal automatisms and true breathing, as the former does not indicate viability or reversibility of brain function. The guidelines provide a framework for the diagnosis of brain death, and adherence to these guidelines is essential to ensure accurate and reliable diagnosis.

Key points to consider in the diagnosis of brain death include:

• The absence of neurologic function with a known irreversible cause of coma
• The presence of apnea, as verified by apnea testing
• The presence of spinal automatisms, which do not indicate true breathing or contradict the diagnosis of brain death
• The importance of experienced clinicians in making the diagnosis of brain death
• The need for appropriate documentation of all aspects of the clinical examination, including the apnea test.

From the Research

Brain Death and Respiratory Movements

• The diagnosis of brain death is based on the irreversible loss of brain function, including the absence of brainstem reflexes and verified apnea 2.
• However, some patients with brain death may still exhibit spontaneous or reflex movements, including respiratory-like movements, which can be attributed to spinal reflexes 3, 4, 5.
• These movements can be observed in up to 40-50% of heart-beating cadavers and do not preclude the diagnosis of brain death or organ transplantation 5.

Spinal Reflexes in Brain Death

• Spinal reflexes, such as plantar response, myoclonus, and triple flexion reflex, can occur in brain dead patients, especially when they become hemodynamically stable after treatment in the organ procurement unit 3.
• Decerebrate-like posturing, which can be mistaken for brain stem reflexes, has been reported in some cases of brain death and is thought to be of spinal origin 4.
• The presence of spinal reflexes in brain dead patients highlights the importance of awareness and education among healthcare providers to avoid confusion and delays in diagnosis and organ donation 3, 4, 5.

Pathophysiological Mechanisms

• The exact pathophysiological mechanisms of spinal reflexes in brain death are not fully understood, but they are thought to be related to the preservation of spinal cord function despite the loss of brain function 6, 5.
• The diagnosis of brain death should be based on a comprehensive evaluation of brain function, including the absence of brainstem reflexes, apnea, and other signs of brain death, rather than the presence or absence of spinal reflexes 2, 6.