The criteria used to diagnose both circulatory and brain death in a patient are subject to variability and as such can be controversial.
“Before the technological advances of the last century, death was diagnosed by presence of coma, apnoea, and lack of a pulse,” said Ricard Valero, Senior Consultant Anaesthesiologist at the Hospital Clínic de Barcelona, and Associate Professor of Anaesthesiology at University of Barcelona, Spain. “The failure of the cardiovascular or respiratory systems inevitably led to a person dying.”
However, the establishment of the criteria determining neurological death during the 20th century represented a significant change regarding the traditional method to define death and still is a challenge from the ethical and scientific point of view. “For this diagnosis, it is essential to demonstrate irreversible coma, absence of response to stimuli and absence of brainstem reflexes (including the capacity to breathe), once the situations that could interfere with the diagnosis have been discarded,” said Valero. “However, several studies have demonstrated that there is no global consensus on what are the detailed diagnostic criteria for this determination in clinical practice, such as the number of physicians needed to agree on the diagnosis.
“Biological death is not an event, but a process,” concluded Valero. “Anaesthetists participate in the decision-making around this process, and we have to establish clear and unequivocal criteria for the diagnosis of death, knowing the emerging ethical implications.”
Dr Alex Manara, Consultant in Anaesthesia and Intensive Care Medicine & Regional Clinical Lead in Organ Donation in Bristol, discussed the circulatory criteria to confirm death. Unlike brain death there has been virtually no guidance until recently to standardise the circulatory-respiratory criteria.
He proposed that there needs to be consensus around a practical and concrete definition of death that describes the state of human death based on measurable and observable biomedical standards with nothing open to interpretation, and urged for a research agenda to address outstanding knowledge gaps in this complex field.