The brain dead donor may produce inadequate amounts of antidiuretic hormone (ADH) from the posterior pituitary resulting in urine volumes of over 1000 mL/hour, resulting in diabetes insipidus. This frequently causes hypernatremia, which can affect the funciton of the transplant in the organ recipient. Diabetes insipidus contributes to hyperosmolarity, hemodynamic instability, and electrolyte abnormalities.
Volume replacement milliliter for milliliter with D5 in water can replete volume if the urine output is less than 200 mL per hour. It is appropriatly managed with desmopressin in patients with higher urine output, with the goal of keeping urine output between 100 to 200 mL/hour. Desmopressin is an ADH analogue, speicific for the V2 receptor with antidiuretic, but no vasopressor activity. It can be given subcutaneously, intramuscularly, intravenously, or intranasally and acts for 6 to 20 hours. Fluid replacement and electrolyte supplementation should be based on serum electrolytes that should be monitored every two to four hours.
- Kenneth E Wood, Bryan N Becker, John G McCartney, Anthony M D’Alessandro, Douglas B Coursin Care of the potential organ donor. N. Engl. J. Med.: 2004, 351(26);2730-9