Dr Andy Ho ("Do not leave definition of death just to doctors"; last Saturday) cast doubts on the validity of brain death as a diagnosis of death and the practice of organ donation by brain-dead donors.

In Singapore, the criteria for determining death are set out in the Interpretation Act (Section 2A).

This provides the context in which organ donation in Singapore is permitted under the Human Organ Transplant Act and the Medical (Therapy, Education and Research) Act.

Brain death is diagnosed only when there is catastrophic irreversible brain injury and is determined according to strict clinical criteria, similar to those adopted in the United Kingdom and Australia.

When brain death has occurred, blood flow and oxygen delivery to the brain ceases irreversibly and all brain functions (including capacity for consciousness and ability to breathe spontaneously) are lost and will never return.

Dr Ho argued that "the (brain-dead) person on the ventilator is still warm... " but the bodily functions are artificially supported through the support machines in the intensive care unit (ICU), which will stop once the organ support is withdrawn.

Dr Ho quoted a study in which 80 brain-dead persons were supported for between two weeks and more than a year, but failed to mention that none of them eventually woke up or recovered.

Circulatory death is defined by the permanent cessation of the body's circulation leading to death of the brain, not by the absence of a heartbeat or the death of the heart.

When a person undergoes coronary artery bypass surgery, the heart and breathing are stopped for at least 30 minutes, yet such a person is not declared dead.

Therefore, in both circulatory death and brain death, there is a permanent loss of brain functions.

In circulatory death, the permanent cessation of circulation leads to death of the brain, while in brain death, brain function is lost first with the circulation maintained by support machines.

Events leading to death always occur suddenly and unexpectedly. The next of kin are often in a state of shock and struggling to deal with their loved one's illness and uncertainties.

In this difficult situation, communication with the next of kin, by the medical team in the ICU and early involvement of the medical social worker, needs to be conducted honestly and sensitively, providing information at a pace they can cope with and understand.

Kwek Tong Kiat (Associate Professor)
Senior Consultant
Hospital Services Division
Ministry of Health
Senior Consultant
Department of Anaesthesiology, Intensive Care and Pain Medicine
Tan Tock Seng Hospital

Jason Phua (Dr)
President
Society of Intensive Care Medicine (Singapore)
Head and Senior Consultant
Division of Respiratory and Critical Care Medicine
University Medicine Cluster
National University Hospital

Lee Heow Yong (Dr)
Director/Hospital Services Division, Health Services Group
Ministry of Health