The Diagnosis And Confirmation of Death
Dying is a process rather than an event which, once begun, will lead to the death of every cell in the body. Some cells can live much longer than others without oxygen or nutrients. For example brain cells begin to die after a matter of a few minutes whereas cells in the eye and skin can survive for 24 hours or more after the heart has stopped. Because dying is a process, it is necessary to identify when the process reaches the point of death and a living human being can no longer exist. Death therefore is not when every cell in the body has died but when an individual suffers an irreversible loss of the capacity to be conscious combined with the irreversible loss of the capacity to breathe. This occurs when vital centres in the brain stem, or base of the brain, are damaged beyond repair. Such damage can occur when the brain itself is injured, such as in an accident, or can occur indirectly by starving the brain of oxygen, such as when the heart stops beating.
The diagnosis of death is required in a number of different situations both as a result of a natural process, such as when the heart stops beating, and when artificial interventions, such as a ventilator or breathing machine, are sustaining the function of the heart and lungs when a patient has independently and irreversibly lost the ability to breathe and to be conscious.
Death Following Cessation of Cardiorespiratory Function
The majority of people die when their cardiorespiratory system, their heart and lungs, cease to function. It may be expected that this will happen, when death is anticipated, or maybe unexpected, perhaps following a sudden cardiorespiratory arrest and failed resuscitation. In either circumstance the cessation of the cardiorespiratory system may result in irreversible damage to the vital centres in the brain stem as previously mentioned. Death can be diagnosed when a medical practitioner, or other appropriately trained and qualified individual, confirms the irreversible cessation of neurological (brain), cardiac and respiratory activity. Diagnosing death in these circumstances requires confirmation that there has been irreversible damage to the brain stem because of the length of time that there has been no blood, and therefore no oxygen, circulating to the brain.
Unless the individual has been dead for sometime and there are clear signs of death, such as rigor mortis, it is recommended that the point after the cessation of cardiorespiratory function, when the death of an individual can be confirmed, is identified by the following conditions;
- There is simultaneous and irreversible loss of breathing and consciousness in the absence of a blood circulation.
- That, where appropriate, full and extensive attempts at reversing any cause of cardiorespiratory failure have been made.
Before confirming death the medical practitioner should ensure that;
- either, the individual meets criteria for not attempting cardiorespiratory resuscitation (this will be the case for expected deaths)
- or, attempts at cardiorespiratory resuscitation have failed
- or, treatment(s) aimed at sustaining life have been withdrawn because it has been decided that it is no longer of benefit to the individual and to continue treatment would not be in their best interest
To confirm death the medical practitioner will;
- observe the individual for a minimum of 5 minutes to establish that irreversible cardiorespiratory arrest has occurred, this will be done by confirming that there is no central pulse or a heartbeat
If during this period the individual shows a sign of a spontaneous return of either their cardiac or respiratory function then a further 5 minutes of observation should occur following a subsequent cessation of their cardiorespiratory function.
The time of death is recorded as the time at which the above criteria have been met.
Death Following the Irreversible Cessation of Brain-Stem Function (Confirmation of death by neurological criteria)
The irreversible cessation of the function of the brain-stem, whether as a result of an intra-cranial (inside the brain) event, such as a brain haemorrhage, or as a result of an extra-cranial event, such as a lack of oxygen, will produce the irreversible loss of consciousness and the ability to breathe and therefore irreversible cessation of the function of the brain-stem equates with the death of the individual and allows the medical practitioner to diagnose death. In these circumstances, even if the body of the deceased remained on respiratory support (a ventilator), the permanent loss of these functions will inevitably lead to deterioration and the heart will inevitably stop beating, although the time over which this occurs may vary. Therefore the individual is dead even though it is possible to artificially maintain cardiorespiratory function for a limited period of time.
In these circumstances in order to diagnose death by using neurological criteria to confirm the lack of brain-stem function the medical practitioner must first;
- Confirm the cause of the individual’s brain damage and that the condition is irreversible
- Ensure that the individual’s clinical condition is not caused by the use of any depressant drugs taken either by the individual when conscious or prescribed whilst in hospital
- Ensure that the clinical condition is not as a result of primary hypothermia
- Ensure that any potentially reversible clinical conditions have been excluded as a cause of the lack of consciousness or loss of ability to breathe.
Once all of the above pre-conditions have been met the medical practitioner will perform a number of tests at the patient’s bed-side to confirm the lack of any brain-stem reflexes thus confirming the irreversible loss of brain-stem function and thus the individual’s death. There are six tests and each test will be performed twice by two different medical practitioners, one of whom is a Consultant but both of whom have been registered for more than five years and are competent in the conduct and interpretation of the tests.
One of the most important tests is the test to ensure that there is no respiratory response when the individual is disconnected from the ventilator. Disconnection would normally be for a period of five minutes. Prior to disconnecting the ventilator the level of carbon dioxide in the individual’s blood would be artificially raised to ensure that it is above the threshold that would normally trigger the respiratory system. In addition during the period of disconnection oxygen would be infused into the body to ensure that the major organs are adequately oxygenated to avoid any damage.
Although death is not confirmed until the second set of tests have been completed the legal time of death is the time of the completion of the first set of tests.
Further and more detailed information can be found in the Academy of Medical Royal Colleges publication A Code of Practice for the Diagnosis and Confirmation of Death 2008.
The possibility of organ and/or tissue donation should always be considered following an individual’s death or when confirmation of death is likely, particularly in circumstances where death is being confirmed by neurological criteria or where further treatment is not considered to be appropriate or in the best interests of the individual and will be withdrawn. Further information about organ donation can be found in the Intensive Care Society publication Guidelines for Adult Organ and Tissue Donation via www.ics.ac.uk.
If organ and/or tissue donation is a possibility it is important that the medical practitioners responsible for the confirmation of death are not members of the transplant team.
The National Kidney Federation cannot accept responsibility for information provided. The above is for guidance only. Patients are advised to seek further information from their own doctor.