The determination of death and organ donation

1961

CoverRecent coverage in the media on death determination and organ donation has left some Canadians with the false impression that there is an unclear understanding of death in this country. Inferences were made that donation and transplantation procedures occur before a donor has actually died, and their family members are being misled to think otherwise. This is simply not true.

Organ donation saves lives. The majority of life-saving and life-preserving organ transplants occur through a process known as deceased donation, whereby organs are removed after death has been determined. Deceased organ donation can therefore occur when a person has been declared dead because either their heart or  brain has completely and permanently stopped working.

Guidelines for both forms of deceased donation are in place and have been for many years in Canada . These guidelines include full disclosure and informed consent, the separation of duties of medical teams who are caring for critically ill patients from medical teams who perform organ transplantation, and rigorous standards for determining death, which must be performed by two physicians  who are independent of transplant teams. As well, the guidelines stipulate that no transplant surgical procedures may start before a patient has died.

MORE: ACETAMINOPHEN: WHAT YOU NEED TO KNOW

It is important to understand that after death is determined and life has ended, the brain is no longer able to function. Despite how recent death is,  donors are not able to experience any pain or suffering during the donation process.

Of course any discussion about death should never minimize the profound, emotional, psychological and spiritual impact that the loss of a loved one has on family and friends. Discussions about death are difficult given the emotional and sensitive subject matter.  There are philosophical, religious, and cultural differences when it comes to defining death and a lack of understanding and awareness, not just amongst the public, but health professionals as well. Despite these challenges and various dimensions, it is important to understand how death remains first and foremost, a biological process.

Over the last 50 years, the advances in medicine, biology, and technology have been remarkable and have helped us in two major ways: by saving patients and by helping us understand the biology of life and death. The specialties that have led to improving our understanding of this domain include: cardiopulmonary resuscitation and physiology; cardiac surgery and cardiopulmonary bypass; ICU-based life support; extracorporeal support and extracorporeal membrane oxygenation (ECMO); cell biology and organ donation, preservation and transplantation. These advances have been truly astonishing in the collective effort to save lives. They have also informed, and complicated, how medicine and modern society understands what it means to be alive or dead.

In the ICU, during the treatment of life-threatening illnesses, sustaining life is based on delivering oxygen and nutrients to cells, specifically, to the mitochondria of the cells. This process provides energy for metabolic processes required for life. Trillions of cells are grouped together and make up our organs – all distinct structures with very distinct functions. Vital organs have basic functions; the lungs provide oxygen to the blood, the heart is the pump that circulates the blood containing oxygen, the liver metabolizes and the kidney filters. The role of acute care and ICU professionals is to treat organ failure by recognizing life-threatening conditions and to intervene with life-sustaining treatments to prevent death.

Technologies that support vital organs can sustain life in order for time or treatment to reverse the life-threatening condition. These complex, resource intensive and arduous treatments are extraordinarily successful, with survival rates around 98 per cent in children and 85 per cent in adults. These treatments are fundamentally directed to provide oxygen delivery to the body. Without oxygen delivery, cells and organs stop working.

The dying process, which can be interrupted by life-saving intervention, is sequential and predictable. In general, death occurs by one of three mechanisms:

1) A primary respiratory illness/event causes breathing to stop, resulting in a fall in oxygen levels in the blood, which finally causes the heart to stop pumping;

2) Primary heart disease such as a heart attack – the heart arrests and cannot pump; and

3) Catastrophic brain injury – the brain stops working, the brain’s control of breathing is lost, breathing stops, oxygen drops and the heart stops beating.

Remarkable advancements in technologies and transplantation permit the interruption of this dying process by supporting or replacing failing organs, with the assumption that time and/or treatment will reverse the disease. Organs can now be supported by machines such as artificial hearts (ventricular assist devices), artificial kidneys (dialysis machines or blood filtration systems), breathing machines that effectively push oxygen into the blood stream or artificial lungs that completely replace lung function. These treatments and technologies can be used inside the body or deployed outside the body. Examples of extracorporeal, or outside of the body technologies, include ECMO (extracorporeal membrane oxygenation) for respiratory failure or cardiac arrest and heart-lung bypass machines used for open heart surgery. It is an incredible achievement to be able to provide patients access to these complex heart/lung/kidney machines that can pump and circulate, oxygenate and filter blood. They can completely replace the total arrest of heart/lung/kidney function. If that is the case, then how does one die?

These technologies serve as so called ‘bridges.’ If the underlying life-threatening organ failure can improve with time or treatment, these technologies are ‘bridges to recovery.’ If the failing organ cannot recover, they may become ‘bridges to transplant,’ but only if an organ transplant becomes available in time. In many unfortunate cases, when recovery is not possible and transplant is not an option or is unavailable, these technologies effectively become onerous ‘bridges to death.’ In this case, the technologies allow us to keep organs of the body working artificially, even when all effective treatment options are exhausted. Unfortunately, this is a circumstance many families find themselves in when a loved one has a non-recoverable illness and, based on the expert opinions of the health care team, must choose whether it’s time to stop life-sustaining treatment.

MORE: THE VACCINE CONTROVERSY

In ICU’s‘ across Canada and worldwide, a decision to withhold and withdraw life-support is the most common event preceding death. The goals of care change from life saving to comfort measures. In Canada, it is a decision that can only be made by the family, consistent with the wishes and values of the patient. The vast majority of these deaths are not eligible for organ donation and in all cases,  it is a decision made independent of consideration of organ donation.

The one organ that cannot be replaced or supported is the most complicated and important – defining who we are and what we are – the brain. The brain is responsible for our ability to breathe independently. It controls consciousness, awareness, sensation, movement, thinking, feeling and acting as well as brainstem reflexes and interaction/exchange of information with our environment. Most treatments, in supporting or replacing failing organs, are dedicated to preserving or restoring brain function. Regardless of the severity of the brain injury or the degree of the coma, the body and the organs can be kept alive indefinitely by replacing breathing with a machine (one that provides oxygen to the blood in order to keep the heart beating) and attentive ICU care. There are many diseases that cause catastrophic brain injuries such as stroke, trauma, oxygen deprivation, and brain hemorrhage. If there is any degree of residual brain function, no matter how minimal, the patient is still alive and decisions to start, stop, or continue life-sustaining treatments are made by the family based on the advice provided by the medical team.

However, the most extreme form of brain injury is brain death. It is better understood as ‘brain arrest,’ which is the complete and permanent cessation of all clinical functions of the brain. All functions of the brain have been lost and they will never resume – no ability to breathe independently, no capacity for consciousness, no awareness, no sensation, no thinking, no feeling, no acting, no brainstem reflexes and no interaction/exchange of information with the environment – the person has died.

It is important to note that the majority of these cases are associated with complete arrest of blood flow to the brain. Organs that do not have oxygen delivery cannot function. In accordance with deceased donation guidelines, in the presence of a clear cause of the brain injury, after reversible or confounding conditions are carefully excluded, and a detailed neurological examination is performed by two physicians separate from the transplant team, the person is declared dead by neurological determination. However, as long as the body remains on a breathing machine, the remaining organs can retain function.  Once the determination is made, the person is medically and legally dead, the breathing machine will be stopped and the option for organ donation is offered to the family.

Confusion has arisen with recent media cases of brain death in pregnancy. After brain death it is possible to sustain organ function with mechanical breathing, infection control, hormone replacement and diligent ICU care for long periods of time to allow for fetal development to mature birth. Effectively, these pregnant but brain dead mothers serve as life support systems for the baby, similar to extracorporeal life support systems such as ECMO, until the fetus is viable. It does not change the medical and legal fact that the mother remains a dead person with an artificially sustained body to allow the baby to be delivered, after which organ support systems are terminated.

Death that is correctly diagnosed by neurological criteria is not reversible – there is no chance of recovery of brain function. Rare reports of ‘miraculous recovery’ of such patients are misleading – these cases are patients who did not have the full diagnostic criteria for the neurological determination of death applied by experienced physicians. In Canada, the requirements across the country are uniform and include diagnostic requirements, clinical checklists and a minimum of two physicians with experience and expertise to prevent the possibility of error.

In public surveys, more than 90 per cent of Canadians support organ donation and transplantation. There are over 4,000 Canadians waiting for an organ transplant and in 2012, 230 Canadians died waiting for an organ transplant while more than 2,200 transplants were performed. In Canada, if you require a life saving organ transplant, you have a 30-40 per cent chance of never receiving one.

While brain death is a principal source for organ donation, donation after circulatory death (DCD, cardiac death) has re-emerged as an option in Canada. DCD has been a well-established form of donation in many countries for many years—like the US and the UK—and accounts for 20 -50 per cent of deceased donation in well-established regions.  This form of donation is still relatively new in Canada, as we have taken a prudent and planned approach.

In response to the Canadian Transplant Community asking ‘why is Canada not doing DCD’, the Canadian Council for Donation and Transplantation (now Canadian Blood Services) sponsored a forum in 2005, hosting 120 national and international experts. During the forum, rigorous discussions were had about whether or not Canada should perform DCD. The answer was yes and, together, they created the recommended guidelines that are now available to hospitals across the country. That was nine years ago. As part of this expert consensus, public and professional surveys showed strong support for DCD and trust in the system. Since 2006, there have been more than 360 Canadians who donated organs after circulatory (cardiac) death, and more than 1,000 transplants would not have occurred if this donation option was not available to Canadian families. Ontario has been a DCD leader, accounting for 75 per cent of donors in Canada. DCD programs have been implemented in British Columbia, Edmonton, Ontario, Quebec and Nova Scotia. Manitoba and Saskatchewan are in the process of developing DCD policies.

The goal of every ICU team is to save lives. They work closely with the family of critically ill patients, making consensual decisions about starting, continuing and—only when a life cannot be saved—withdrawing life-sustaining treatments. The dying patients who are candidates for DCD are generally patients with catastrophic brain injury, not brain dead but with some residual brain function and a very poor prognosis for meaningful recovery. Their families have made the decision to stop life sustaining treatments. In these cases, the ICU teams manage end-of-life care, ensuring relief of suffering, comfort and dignity. For patients who are candidates for organ donation and whose families have given their consent for donation, it is also the sole responsibility of the ICU team to determine death according to national organ donation guidelines. In the case of donation after cardiac death, it is required that two physicians must be present to monitor and document the absence of a pulse, breathing and blood pressure for a period of no less than five minutes. The transplant team has no role in any of these duties.

MORE: ROBOTIC SURGERY: IS IT SAFE?

The brain stops working prior to or within 20 seconds after a cardiac arrest so it is impossible for donors to experience suffering.

In medicine, death is defined as the complete and permanent cessation of heart function or brain function. Canada is a world leader in establishing the ethical and medical practices on the determination of death and donation. In May 2012, in collaboration with the World Health Organization (WHO) and international experts who care for critically ill patients who may die, Canadian Blood Services organized and hosted a meeting as part of the first phase in the process for the development of International Guidelines for the Determination of Death. The report from this meeting has been published recently in the journal Intensive Care Medicine. The report supports current practices in Canada and reaffirm Canada’s leadership in ethical and medical conduct and procedures regarding death determination.

The loss of a loved one is tragic. Organ donation is wonderful act at the worst time – the juxtaposition of an unavoidable death in a willing donor to a preventable death in a transplant recipient. This gift, this benevolence, is predicated on the public trust of the health care system, based on the first and foremost priority to save the life of the ill and injured whenever possible. If not possible, then we care for patients at the end of their life and when possible, provide the option of organ donation.