Wednesday, 17 April, 2024
HomeTalking PointsExperts differ on when to declare a patient dead

Experts differ on when to declare a patient dead

Debate is simmering over the Uniform Determination of Death Act – a law adopted by most US states in the 1980s saying death can be declared if someone has experienced “irreversible cessation of all functions of the entire brain” – but calls are growing from various quarters for the statute to be revised.

Many experts say the discrepancy needs to be resolved to protect patients and their families, maintain public trust, and reconcile what some see as a troubling disconnect between the law and medical practice.

The debate became so contentious, however, that the Uniform Law Commission, the group charged with rewriting model laws for states, paused its process last summer because participants couldn’t reach a consensus, reports NPR.

Thaddeus Pope, a bioethicist and lawyer at Mitchell Hamline School of Law in St Paul, Minnesota, said there was “a lot of conflict at the bedside over this at hospitals across the US”.

“Let’s fix it before it becomes a crisis. It’s such an important question that everyone needs to be on the same page.”

Criteria for brain death are the challenge

There are two ways doctors can declare someone dead. The original method, the most common, is known as circulatory death: when someone stops breathing permanently and their heart stops beating permanently, such as from a heart attack.

This method is applicable if CPR or breathing machines are unsuccessful or will not be used.

The second method, brain death, can be declared after catastrophic brain injury has caused the permanent cessation of all brain function, but when patients’ hearts are still pumping through the use of ventilators or other artificial forms of life support.

For years, doctors have declared brain death using a series of tests to determine four main criteria: whether a person has a profound and irreversible coma, has permanently lost the capacity to breathe, has permanently lost all reflexes controlled by the brainstem, and whether all potentially reversible conditions, such as a drug overdose, have been ruled out.

But other parts of the brain may continue to function. Specifically, attention has focused on the hypothalamus, which helps manage very basic bodily functions like temperature, blood pressure and hormones.

“The law says you’re not dead until all the functions of your entire brain have stopped – every single function of the entire brain,” said Pope. “Well, there is a function of your brain that may continue, and we’re still going to say that you’re dead.”

Critics point to rare cases like Jahi McMath, a 13-year-old girl who was declared brain dead in 2013. Her family refused to withdraw life support for years. She continued to grow and even went through puberty.

Jahi never recovered and eventually died. But her case and others have prompted calls to change the law.

“I’ve never heard of a corpse undergoing puberty before,” said Dr Alan Shewmon, a professor emeritus of paediatrics and neurology at the David Geffen School of Medicine, UCLA, who has long questioned the use of brain death.

“She was clearly not dead. Yet she was declared dead. I think it’s a tragedy. How many others are potentially like that but we never find out?”

When does hope for recovery end?

But other neurologists and bioethicists argue that there’s no way to confirm every neuron in the brain has ceased functioning. Even if someone still has activity in some parts of the brain, such as the hypothalamus, they won’t wake up or recover if they have been declared brain dead correctly through current testing, they say.

“They do not have any hope for meaningful recovery or any hope for regaining of consciousness or brainstem function,” said Dr David Greer, chair of neurology at the Boston University Chobanian & Avedisian School of Medicine.

“They’ve had a neurological catastrophe. So if you want to call them not dead, what does that accomplish?”

Greer helped write the latest guidelines from the American Academy of Neurology on how doctors declare brain death, affirming the current testing regimen.

But the American College of Physicians (ACP) recently issued its own position paper embracing the whole-brain standard.

“The American Academy of Neurology proposes putting into law only three specific criteria for the determination of death by neurologic criteria. ACP opposes putting only three criteria into law because doing so would be overly narrow and privileges certain brain functions over others,” said Dr Matthew DeCamp, an associate professor at the University of Colorado School of Medicine, who helped write the ACP position paper.

“The whole-brain standard is a firmer biologic foundation for determining death.”

Some doctors and advocates would like to do away with brain death entirely, while others call for additional testing to rule out functioning of the hypothalamus.

“What we really need to do when we have too many false positives on anything in medicine is improve our testing so it gives fewer false positives,” said Dr Daniel Sulmasy, a bioethicist at Georgetown University.

Pope, the bioethicist at Mitchell Hamline School of Law, would like to see a federal law or regulations that would create a uniform national standard.

“I think of it like a bridge. You don’t wait until the bridge falls into the river. You try to keep it updated and repair it. We’re starting to see cracks. Let’s try to fix the problem before it gets worse.”

Resuscitation

While the debate continues, and with emerging evidence suggesting the brain shows signs of electrical recovery for as long as an hour into ongoing cardiopulmonary resuscitation (CPR), other experts believe people “are giving up too soon on trying to revive individuals”.

They say that this time between cardiac arrest and awakening can be a period of vivid experiences for the dying patient before they return to life – a phenomenon known as “recalled death” – and should be an impetus to increase the use of devices that measure the quality of CPR, and to find new treatments to restart the heart or prevent brain injury.

“If people who go into cardiac arrest receive good quality chest compressions that restore blood flow to the brain, then consciousness is restored, as well,” said Jasmeet Soar, MD, consultant in Anaesthetics & Intensive Care Medicine, North Bristol NHS Trust, and an editor of the journal Resuscitation.

“We know that because if chest compressions are stopped, the person becomes unconscious again,” he told theheart.org | Medscape Cardiology.

“This CPR-induced consciousness has become more common when professionals do the CPR because resuscitation guidelines now place more focus on high-quality CPR: ‘push hard, push fast’.”

“People give up too soon when trying to revive individuals, and should be trying more modern strategies, like extracorporeal membrane oxygenation,” said Sam Parnia, associate professor in the Department of Medicine at NYU Langone Health and director of critical care and resuscitation research at NYU Langone.

Brain activity, heightened experiences

Two types of brain activity may occur when CPR works. The first – CPR-induced consciousness – is when someone recovers consciousness while in cardiac arrest. Signs of consciousness include combativeness, groaning, and eye-opening.

The second type is a perception of lucidity with recall of events, Soar said. “Patients may form memories they can recall. We’re not sure whether that happens during CPR or while the patient is waking up during intensive care, or how the brain creates these memories, or if they’re real memories or coincidental, but it’s clear the brain does form them during the dying and recovery process.”

This latter phenomenon was explored in detail in a recent study led by Parnia, involving 567 in-hospital patients with cardiac arrest from 25 centres in the US and UK: 53 survived, 28 of those survivors were interviewed, and 11 reported memories or perceptions suggestive of consciousness.

Four types of experiences occurred: recalled experiences of death; emergence from coma during CPR/CPR-induced consciousness; emergence from coma in the post-resuscitation period, and dreams and dream-like experiences.

In a complementary cross-sectional study, 126 community cardiac arrest survivors reported similar experiences plus a fifth type, “delusions”, or “misattribution of medical events”.

“Many people label recalled experiences of death as ‘near-death’ experiences, but they’re not,” Parnia said. “Medically speaking, being near to death means your heart is about to stop. But the point is these people are not near death. They actually died and came back from it.”

He said many physicians are taught that somehow after, say, three to five minutes of oxygen deprivation, the brain dies.

“Our study showed this is not true – that the brain may not be functioning, which is why they flatline, but if you’re able to resuscitate them appropriately, you can restore activity up to an hour later.”

The study used EEG monitoring in a subset of 53 patients. Among those with evaluable EEG data, brain activity returned to normal or near-normal after flatlining in about 40% of images; spikes were seen in the delta (22%), theta (12%), alpha (6%), and beta (1%) waves associated with higher mental function.

“The team recorded what was happening in the brain during real-time CPR using various tests of consciousness, including EEG measurements and tests of visual and auditory awareness using a tablet with a special app and a Bluetooth headphone.

“We found that even though the brain flatlines, which is what we expect when the heart stops, with professionally-given CPR even up to about an hour after this, the brainwaves changed into normal to near-normal patterns,” Parnia said.

“We were able to identify these brain waves in patients while they were being resuscitated, confirming that people can have lucid consciousness even though they appear unconscious.”

Potential mechanism

Parnia and his team proposed a potential mechanism for recalled experiences of death. Essentially, when the brain flatlines, the dying brain removes natural inhibitory (braking) systems necessary to support daily functioning.

This disinhibition may open access to “new dimensions of reality, including lucid recall of stored memories from early childhood to death”, he said.

From a clinical perspective, “although the brain stops working when it flatlines, it does not die within five or 10 minutes of oxygen deprivation”.

This is contrary to what many doctors believe, and because of that, he said, nobody has tried to find treatments or new ways to restart the heart or prevent brain injury.

“They think it’s futile. So, with this work, we’ve opened the window to developing cocktails of drugs that could be given to patients, who have technically gone through death, to bring them back to life.”

The findings have ramifications for clinicians caring for patients who survive cardiac arrest, said Lance Becker, MD, professor and chair, Department of Emergency Medicine, Donald & Barbara Zucker School of Medicine at Hofstra/Northwell, New York.

“I’ve talked to a lot of patients who have had some kind of recalled experience around cardiac arrest and some who have had zero recall, as well,” he said. “But very often, clinicians don’t want to listen to their question, don’t think it’s important, and downplay it.

“It’s imperative that doctors listen, learn, and respond.”

Better CPR, new treatments

Experts in emergency and intensive care medicine studying survival after cardiac arrest hope to find ways to save patients before too much damage is done to the brain and other organs from loss of oxygen, Parnia said.

Currently, his team is developing cocktails of treatments. These include hypothermic circulatory arrest – cooling the body to stop blood circulation and brain function for up to 40 minutes – and giving magnesium, a brain-protective treatment, to people whose hearts stop.

Becker would like to see optimal care of patients with cardiac arrest. “The first step is to increase blood flow with good CPR and then measure whether CPR is working,” he said.

Despite the availability of devices that provide feedback on the quality of CPR, they’re rarely used, he added, citing ultrasound devices that measure the blood flow generated during CPR, compression meter devices that go between the patient’s chest and the rescuer’s hands that gauge the rate and depth of compression, and invasive devices that measure BP during CPR.

His group is trying to design even better devices. “An example would be a little probe you could pop on the neck to study blood flow to the brain with ultrasound, so that while you were pumping on the person, you could see if you’re making them better or not.”

Becker, like Parnia, also favours the development of drug cocktails, and his team has been experimenting with various combinations in animal models.

“We think those two things together – ECMO and a drug cocktail – would be a very powerful one to two knock out for cardiac arrest,” he said. “We have a long way to go, 10 or 20 years. But most people around the world working in this area believe that will be the future.”

 

NPR article – Debate simmers over when doctors should declare brain death (Open access)

 

Annals of the New York Academy of Sciences article – Guidelines and standards for the study of death and recalled experiences of death––a multidisciplinary consensus statement and proposed future directions (Open access)

 

Resuscitation article – AWAreness during REsuscitation – II: A multi-centre study of consciousness and awareness in cardiac arrest (Open access)

 

Medscape article – Near-Death Experiences During CPR: An Impetus for Better Care (Open access)

 

See more from MedicalBrief archives:

 

Patients had lucid death experiences after CPR revival, finds study

 

Scientists discover ‘breakthrough’ technique to revive organs after death – Yale study

 

Consensus review: Determination of brain death/death by neurologic criteria

 

 

 

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