Emergency physicians should be familiar with their departmental policies on brain death and organ procurement. Telephone and beeper numbers for the regional organ procurement organization (OPO) should be readily available.
An increasing demand for donor organs, coupled with improvements in transplant immunology, has greatly expanded the pool of patients eligible for organ donation. The donation of tissue such as skin, bones, and corneas can occur even postmortem. Recently the success of solid organ transplantation using non-heart-beating donors promises to expand the possible donor pool by 20 percent.4 Absolute contraindications for transplant donors include HIV, sepsis, and malignancy other than primary central nervous system tumors. Advanced age is a relative contraindication; most OPOs do not harvest solid organs from individuals older than 75.
The Uniform Determination of Death Act provides guidelines outlining the neurologic criteria for the diagnosis of brain death: complete and irreversible loss of brain and brainstem function. Cerebral unresponsiveness, brainstem areflexia, and apnea are necessary to diagnose brain death. Reversible causes of brainstem depression, such as hypothermia and drug intoxication, need to be excluded. OPOs should be notified early of potential organ donors, and the OPO coordinator on call should be called even before the formal declaration of brain death.
Discussion of organ donation with the family is best done separately from discussion and acceptance of brain death. Once brain death has been declared, the OPO coordinator, who is highly trained for this delicate discussion, should broach the subject of organ donation. The emergency physician should focus on identifying possible donor candidates and giving the family a realistic prognosis for the patient. Organ donation consent rates vary widely among OPOs and from hospital to hospital. Consent rates are highest when the family initiates the discussion of organ donation. Consent rates are also higher if the discussion about organ donation is decoupled from the explanation of brain death, as described above. For multiple reasons, families may perceive a mixed message if the physicians caring for their seriously ill relative also initiates discussion of organ donation before the patients are "officially dead."
Following brain death, a number of physiologic changes occur that necessitate intervention to preserve donor organ perfusion. 56 Increasing cerebral edema after trauma or a cerebrovascular accident results initially in elevated catecholamine release and hypertension. With brainstem necrosis, catecholamine levels drop rapidly to 10 percent of normal values, causing hypotension, which must be corrected with fluids and vasopressors. Pituitary necrosis occurs in approximately 75 percent of organ donors, resulting in diabetes insipidus, which, if untreated, can result in significant hypovolemia. Antidiuretic hormone and free-water deficits should be rapidly replaced in these patients.
Body temperature control is often lost due to ischemia of the hypothalamus, with approximately 86 percent of donors developing hypothermia. Hypothermia has many detrimental effects on potential donor organs, including coagulopathy, shifting of the oxygen-hemoglobin dissociation curve, and hepatic and cardiac dysfunction.
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