Brain death / support brain death organ donor

Dr. Sunil Shroff, MS, FRCS ( UK). Dip. Urol ( Lond.).
Dr. S Mahendran, MD, General Medicine

• Evolution of  the concept of brain death
• Diagnosis of brain stem death
• Request for organ donation
• Support of the Brain Dead Organ Donor
• Contraindications to organ donation
• Cardio-respiratory support
• Ventilatory support
• Renal support
• Endocrine changes
• Hyperglycemia
• Other harmones
• Miscellaneous problems
• Conclusion

Endocrine changes

Diabetes insipidus

This should be suspected when urine volumes exceed 300ml/hr (or 7ml/kg/hr) in association with hypernatremia (serum sodium greater than 150mEq/l), elevated serum osmolality(>310mOsm/L) and a low urinary sodium concentration. Desmopressin (dDAVP) should be used in preference to Vasopressin. The latter has undesirable splanchnic and renal vasoconstrictive effects. The dose is titrated to maintain urine outputs of 1-2ml/kg/hr. usual dosages are Desmopressin 1-4 mcg every 8 to 12 hours or Vasopressin 1-4 units/hr. Ocne there is hyernatremia the replacement intravenous fluids should contain free water, i.e. Dextrose and / or half strength (0.45) Normal saline.

Hyperglycemia

This is due to the administration of glucose containing fluids, reduced insulin secretion and increased levels of catecholamines. Hyperglycemia results in an osmotic diuresis and electrolyte disturbances. Blood glucose levels should be controlled with intravenous insulin infusion.

Other hormones

The use of hormonal therapy, Thyroxine, tri-iodothyronine(T3), corticosteriods and insulin, has been advocated to improve cardiovascular stability. At present, such therapy are regarded as experimental.

MISCELLANEOUS PROBLEMS

Infection

Systemic infection is a relative contraindication to organ donation. All unnecessary indwelling devices should be removed. All lines and catheters must be inserted aseptically and meticulous care of dressings and wounds is vital. Tracheal suction should be done with sterile precautions. Appropriate samples from suspected sources of infection should be sent for culture and sensitivity. Treatment should be initiated based on culture reports. Prophylactic antibiotics are indicated only immediately prior to organ retrieval.

Coagulopathy

Disseminated intravascular coagulation is common in patients with traumatic head injuries. This is due to the release of thromboplastin from the injured brain. If it results in clinically significant mucocutaneous bleeding, treatment with appropriate blood components is required.

Hypothermia

Core temperature should be monitored using rectal thermometers. The core temperature should be maintained above 350C. After brain death, the body becomes poikilothermic because of the loss of central temperature control mechanisms. Treatment includes use of humidified and warmed ventilator gases ; warmed intravenous fluids and blood products ; and heating blankets. Sometimes a "hot blower" next to the patient is the best solution to maintain the body temperature.

CONCLUSION:

A severe shortage of organs the world over has led to increased pressure on the intensive care staff for early identification of the brain dead donor and optimum management of this condition. The diagnosis of brain death as per the Transplantation Human Organ Act is based as simple clinical bedside tests. The passing of this Act in 1994 and its subsequent adaptation by many Indian States has made it possible in India to use this pool of patients for organ retrieval and transplantation.