Management of Organ Donors after Brain Death (Part I)

Patients who are determined to be brain dead need aggressive care from the point that brain death is declared until organ procurement. In 2015, The Society of Critical Care Medicine, American College of Chest Physicians, and the Association of Organ Procurement Organizations published a consensus statement on management of the potential organ donor in the ICU. However, there is no universal set of guidelines for this management and there is much variability between transplant centers within the US and abroad in regards to medication selection and dosing.

Usual supportive care for these patients should be continued (VAP prophylaxis, GI prophylaxis, etc). Ventilator management is beyond the scope of this article but data points to using a lung-protective ventilation strategy to optimize the lungs for transplant.

Cardiovascular

Goals: Address sudden hypertension which ensues shortly after brain death

Physiological Challenges: 

1st – Ischemia reaches the pons which causes Cushing’s Reflex (hypertension, bradycardia, irregular respirations)

2nd – Ischemia reaches the medulla which causes a catecholamine surge

Antihypertensives: 

The preferred antihypertensive agent has not been established. Short-acting agents (ex: nicardipine, esmolol) may be preferred due to the short duration of the autonomic storm. Esmolol may be preferred due to its ability to attenuate adrenergic stimulation.

Hemodynamics, Fluids, and Electrolytes

Goals: Maintain MAP > 60, urine output 1-3 mL/kg/hr, and cardiac index > 2.4 L/min for organ perfusion; optimize fluid management

Physiological Challenges:

3rd – Ischemia reaches the brainstem leading to catecholamine depletion and sudden hypotension

Fluids

Studies addressing fluid choice are lacking. Balanced salt solutions may be preferred to avoid hyperchloremic acidosis. Furthermore, uncorrected hypernatremia has been shown to lead to graft loss after liver transplant lending further support to using balanced salt solutions such as LR over normal saline. The selection of fluid may be guided by patient-specific acid-base status and BMP results.

Electrolytes

Imbalances may be due to the hyperglycemic state which occurs after brain death. Imbalances that are not corrected may lead to graft loss after transplantation.

Vasopressors

Dopamine is the preferred agent due to its ability to protect endothelial cells. One study also found that pretreatment with dopamine reduced the need for dialysis after kidney transplantation (interesting considering “renal dose dopamine” is no longer recommended). However, dopamine should not be used in patients with untreated tachyarrhythmias (SOAP II trial anyone?).

Vasopressin is an alternative 1st line agent to dopamine because it augments catecholamine stimulation and can treat DI as well (more on this later in the endocrine section).

Norepinephrine is considered a 2nd line agent. There is conflicting data regarding recipient survival after the donor administration of norepinephrine. One retrospective study found no difference in recipient survival in heart transplant when donors were treated with dopamine vs norepinephrine. However, a subgroup analysis showed that 5 years later, patients who received hearts from donors pretreated with norepinephrine had improved long term survival.