The time between brain death and organ procurement provides an opportunity to intervene in ways that enhance and improve organ preservation and suitability.
Among potential organ donors, declaration of brain death/death by neurologic criteria is unlikely to end the Intensivist’s role in the patient’s care. Conscientious and multi-systemic care of the potential donor continues to be vitally important to ensure the viability of prospective organs for transplantation as well as preventing cardiac arrest, which may occur in up to 10% of patients awaiting transplant. Since there may be a period of up to several days between brain death determination and organ procurement, this period provides an important opportunity to intervene in ways that are likely to enhance and possibly improve organ preservation and suitability for transplantation. The Intensivist and Organ Procurement Office will often work collaboratively towards this end. I will briefly review some of the supportive care after brain death determination.
With severe brain injury, a sympathetic storm is likely to occur that can be associated with increases in blood pressure, heart rate, left ventricular afterload, and pulmonary hypertension, which may lead to myocardial or pulmonary damage. Beta-blocking medications such as esmolol may be helpful in this stage. This may give way to vasoplegia, requiring fluids and/or vasopressors. Recall the vagus nuclei, located in the medulla, are involved with brain death, limiting any parasympathetic outflow and atropine will usually not increase heart rate. Dopamine may be preferred to norepinephrine in these patients, and the exact combination of fluids and vasoactive drugs is suggested by evaluations of the patient’s volume and vasoplegic status. For that reason, patients pronounced brain dead who are awaiting transplantation should generally have central venous catheters and intra-arterial lines placed and occasionally other modalities, such as pulse contour analyses, pulmonary artery catheters, and echocardiographic techniques.
Like other ICU conditions, mean arterial pressure in the 60mm to 70mm range is usually suggested, but this is not strongly evidence-based. Hypovolemia is commonly related to vasodilation and central diabetes insipidus (CDI), which is present in 50% to 80% of patients who are brain dead (the usual definitions of brain death do not exclude residual hypothalamic-pituitary activity, which is common among patients pronounced brain-dead). Normal saline may be preferred to balanced solutions in these patients, and CDI is effectively treated with supplemental desmopressin acetate. Vasopressin infusions may be helpful if CDI is accompanied by hypotension. The serum sodium should be maintained at less than 155 mmoles/L at the highest.
Other Considerations
With brain death, the lungs may suffer injury similar to acute respiratory distress syndrome (ARDS) related to both hydrostatic and inflammatory injury. Some guidelines have previously suggested high tidal volumes in these patients, but current guidelines for ventilator management suggest low tidal volume and lung protective ventilation like that for ARDS in general and particularly if lung transplantation is anticipated. Recruitment maneuvers, generally advised against in ARDS, are sometimes ordered for potential donors.
Corticosteroid supplementation in varied doses is often used to help correct hypothalamic-pituitary insufficiency, stabilize hemodynamics, and lessen inflammatory effects on the transplantable organs. The precise regimen of corticosteroids is somewhat controversial, with lower doses more recently preferred. Thyroid hormone is often given to correct imbalances of the hypothalamic-pituitary axis and promote hemodynamic stability, but its use is not strongly backed by evidence.
Common Complications
Hyperglycemia, even among non-diabetic patients, is common and has been associated with worse outcomes among renal transplants. Relative hypothermia is also common among these patients, and a core temperature greater than 35° is often suggested. Anemia occurs commonly, but an exact transfusion trigger has not been determined; however, a hemoglobin level of at least 7g/dl should be maintained. Enteral but not parenteral nutrition should be given as tolerated.
Coagulopathy is common, particularly disseminated intravascular coagulation, among patients with severe trauma and may be associated with worse outcomes among transplantable organs. Correcting the platelet count to greater than 50,000 and International Normalized Ratio less than 1.5 is reasonable but not strongly evidence-based. Infections are, of course, common in the ICU, and antibiotic coverage for at least 48 hours is reasonable before organ procurement. Care of potential donors with HIV, hepatitis B, or hepatitis C requires expert consultation. Yet, newer anti-viral agents and therapies have allowed some of these patients to be safe organ donors.
As mentioned, up to 10% of potential organ donors suffer cardiac arrest before organ procurement. I do not offer these patients CPR. Although, legally, CPR and other interventions do not require any informed consent from an authorized organ donor, it is certainly wise to discuss these matters fully and frankly with the patient’s family or caregivers.
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