The next steps in organ donation after brain death

Photo credit: Anastasia Usenko

The time between brain death and organ removal offers the opportunity to intervene in a way that promotes and improves the preservation and suitability of the organ.

In potential organ donors, determination of brain death/death by neurologic criteria is unlikely to terminate the intensivist’s role in patient care. Diligent and multisystemic care of the potential donor remains critical to ensure viability of the potential organs for transplantation and to prevent cardiac arrest, which can occur in up to 10% of patients awaiting transplantation. Because there may be a period of up to several days between determination of brain death and organ procurement, this period provides an important opportunity to intervene in a manner that is likely to promote and potentially improve organ preservation and suitability for transplantation. The intensivist and the organ procurement office often work together for this purpose. I will briefly discuss some of the supportive care after determination of brain death.

In severe brain injury, sympathetic storm is likely to occur, which may be associated with increases in blood pressure, heart rate, left ventricular afterload, and pulmonary hypertension, which may result in myocardial or lung damage. Beta-blockers such as esmolol may be helpful at this stage. This may result in vasoplegia requiring fluids and/or vasopressors. Remember that the vagal nuclei in the medulla are involved in brain death and limit any parasympathetic outflow. Atropine does not usually increase heart rate. In these patients, dopamine may be preferable to norepinephrine, and the precise combination of fluids and vasoactive drugs will be suggested by assessments of the patient’s volume and vasoplegic status. For this reason, central venous catheters and intra-arterial lines should generally be placed in patients declared brain dead and awaiting transplantation. Occasionally, other methods such as pulse contour analysis, pulmonary artery catheters and echocardiographic techniques should also be used.

As with other ICU settings, a mean arterial pressure in the range of 60 mm to 70 mm is usually recommended, but this is not strongly evidence-based. Hypovolemia is frequently associated with vasodilation and central diabetes insipidus (CDI), which is present in 50 to 80% of brain-dead patients (common definitions of brain death do not exclude residual hypothalamic-pituitary activity, which is common in brain-dead patients). In these patients, normal saline is preferable to balanced solutions, and CDI is effectively treated with additional desmopressin acetate. Vasopressin infusions may be helpful when CDI is accompanied by hypotension. Serum sodium levels should be maintained at or below 155 mmol/L.

Further considerations

In brain death, the lungs may be damaged in a manner similar to acute respiratory distress syndrome (ARDS), which is due to both hydrostatic and inflammatory damage. Some guidelines have previously recommended high tidal volumes in these patients, but current guidelines for ventilator therapy recommend low tidal volumes and lung-protective ventilation as in ARDS in general and especially when lung transplantation is anticipated. Recruitment maneuvers, generally discouraged in ARDS, are sometimes ordered for potential donors.

Corticosteroid supplements in varying doses are often used to correct hypothalamic-pituitary insufficiency, stabilize hemodynamics, and reduce inflammatory effects on transplantable organs. The exact dosing of corticosteroids is somewhat controversial, with lower doses recently favored. Thyroid hormones are often given to correct hypothalamic-pituitary axis imbalances and promote hemodynamic stability, but their use is not supported by sufficient evidence.

Common complications

Hyperglycemia is also common in nondiabetic patients and is associated with worse outcomes in kidney transplants. Relative hypothermia is also common in these patients, and a core body temperature of over 35°C is often suspected. Anemia is common, but an exact transfusion trigger has not been determined; however, a hemoglobin level of at least 7 g/dL should be maintained. Enteral, but not parenteral, nutrition should be given as tolerated.

Coagulopathies, particularly disseminated intravascular coagulation, are common in patients with severe trauma and may be associated with worse outcomes in transplantable organs. Correction of platelet counts to over 50,000 and an International Normalized Ratio of less than 1.5 is reasonable but not strongly evidence-based. Infections are of course common in the ICU and antibiotic treatment for at least 48 hours before organ procurement is reasonable. Management of potential donors with HIV, hepatitis B or hepatitis C requires expert advice. However, newer antiviral agents and therapies have enabled some of these patients to be safe organ donors.

As mentioned above, up to 10% of potential organ donors experience cardiac arrest prior to organ collection. I do not offer CPR to these patients. Although CPR and other procedures do not legally require informed consent from an authorized organ donor, it is certainly advisable to discuss these matters in detail and openly with the patient’s family or caregivers.