There have been a number of cases whereby patients' vital signs have returned after being declared dead.
After 17 minutes of resuscitation efforts - incorporating CPR, defibrillation, and medication - the man's vital signs failed to return, and he was pronounced dead. Ten minutes later, his surgeon felt a pulse. He was alive. The man's operation continued, with a successful outcome.
In 2014, a 78-year-old man from Mississippi was declared dead after a hospice nurse found him with no pulse. The next day, he woke up in a body bag at the morgue.
These are undoubtedly extraordinary stories that sound more suited to a horror movie, but there is a real-world name for such cases: Lazarus syndrome.
What is Lazarus syndrome?
The Lazarus phenomenon, or Lazarus syndrome, is defined as a delayed return of spontaneous circulation (ROSC) after CPR has ceased. In other words, patients who are pronounced dead after cardiac arrest experience an impromptu return of cardiac activity.
The syndrome is named after Lazarus of Bethany, who - according to the New Testament of the Bible - was brought back to life by Jesus Christ 4 days after his death.
Lazarus syndrome is the return of spontaneous circulation after CPR has been stopped.
Since 1982, when the Lazarus phenomenon was first described in medical literature, there have been at least 38 reported cases.
According to a 2007 report by Vedamurthy Adhiyaman and colleagues, in around 82 percent of Lazarus syndrome cases to date, ROSC occurred within 10 minutes of CPR being stopped, and around 45 percent of patients experienced good neurological recovery.
But while the low number of report cases might highlight the rarity of Lazarus syndrome, scientists believe that it is much more common than studies suggest.
"The Lazarus phenomenon is a grossly underreported event," notes nephrologist Dr. Vaibhav Sahni in a 2016 report.
"The reason for these can be attributed to the fact that medicolegal issues are brought to light in cases which are pronounced dead which later turn out to have been alive," he explains. "The professional expertise of the resuscitating doctor can be brought into question, not to mention the fact that such an event can lead to disrepute among colleagues."
"Another pertinent question that arises is whether the death of a particular patient occurred as a result of premature cessation of resuscitative efforts or the omission of continued resuscitation," he adds.
Precisely what causes the Lazarus phenomenon remains unclear, but there are some theories.
What might cause Lazarus syndrome?
Some researchers suggest that the Lazarus phenomenon may be down to a pressure buildup in the chest caused by CPR. Once CPR is ceased, this pressure may gradually release and kick-start the heart back into action.
Another theory is the delayed action of medication used as a part of resuscitation efforts, such as adrenaline.
"It is possible that drugs injected through a peripheral vein are inadequately delivered centrally due to impaired venous return, and when venous return improves after stopping the dynamic hyperinflation, delivery of drugs could contribute to return of circulation," explain Adhiyaman and colleagues.
Hyperkalemia - whereby blood levels of potassium are too high - is another proposed explanation for the Lazarus phenomenon, as it has been linked to delayed ROSC.
Because so few cases of Lazarus syndrome are reported, uncovering the exact mechanisms behind the condition is tricky.
But perhaps it is not what is bringing a patient back to life that we should be concerned about; maybe they were never deceased.
Mistaking the living for the dead
As Benjamin Franklin once said, "In this world nothing is certain but death and taxes." In a clinical setting, however, a declaration of death is not as certain as one might think.
In 2014 came a report of an 80-year-old woman who had been "frozen alive" in a hospital morgue after being wrongly pronounced dead.
In the same year, a New York Hospital came under fire after incorrectly declaring a woman as brain dead following a drug overdose. The woman awoke shortly after being taken to the operating room for organ harvesting.
Cases such as these beg the question, how is it even possible to mistakingly declare a person as dead?
There are two types of death: clinical death and biological death. Clinical death is defined as the absence of a pulse, heartbeat, and breathing, while biological death is defined as the absence of brain activity.
Looking at these definitions, you might assume that it would be easy to tell when a person is deceased - but in some cases, it is not so simple.
There are a number of medical conditions that can make an individual "appear" dead.
Hypothermia, catalepsy, and locked-in syndrome
One such condition is hypothermia, whereby the body experiences a sudden, potentially fatal drop in temperature, normally caused by prolonged exposure to the cold.
Hypothermia can cause heartbeat and breathing to slow, to the point where it is almost undetectable. It is believed that hypothermia led to the mistaken death of a newborn baby in Canada in 2013.
There are a number of conditions in which a patient might 'appear' to be deceased.
The baby in question was born on a sidewalk in freezing cold temperatures. Doctors were unable to detect a pulse, and the baby was declared dead. Two hours later, the baby started moving.
Dr. Michael Klein, of the University of British Columbia in Canada, said that the baby's exposure to such cold temperatures may explain the situation. "The whole circulation would have stopped but the neurological condition of the child could be protected by the cold."
Catalepsy and locked-in syndrome are examples of other conditions in which the living could be mistaken for dead.
Catalepsy is characterized by a trance-like state, slowed breathing, reduced sensitivity, and complete immobility, which can last from minutes to weeks. The condition may arise as a symptom of neurological disorders such as epilepsy and Parkinson's disease.
In locked-in syndrome, a patient is aware of their surroundings, but they experience complete paralysis of voluntary muscles, with the exception of muscles that control eye movement.
In 2014, The Daily Mail reported on 39-year-old British woman Kate Allatt, who had locked-in syndrome.
Unaware of her condition, doctors declared her brain dead. Medics, family, and friends stood by her bedside and discussed whether or not to switch off her life support. Allatt heard everything, but she was unable to tell them that she was fully conscious.
"Locked-in syndrome is like being buried alive," said Allatt. "You can think, you can feel, you can hear, but you can communicate absolutely nothing."
Confirming death beyond doubt
If this article has sent a shiver down your spine, fear not; Lazarus syndrome is extremely rare, as is the possibility of being wrongly declared as deceased.
That said, the fact that such cases have even occurred has raised questions about death recognition and confirmation in a clinical setting.
Some researchers suggest that doctors should wait 10 minutes after CPR is stopped to see whether a patient's vital signs return.
According to Adhiyaman and colleagues, some researchers have suggested that patients should be "passively monitored" for 10 minutes following death, as that is the time frame in which delayed ROSC is most likely to occur.
"Death should not be certified in any patient immediately after stopping CPR," the researchers write, "and one should wait at least 10 minutes, if not longer, to verify and confirm death beyond doubt."
When it comes to organ donation, however, other researchers note that waiting as long as 10 minutes to see whether ROSC might occur could be detrimental.
Current guidelines recommend 2 to 5 minutes of observation after the heart has stopped beating before declaring death; the longer the blood flow to the organs is restricted, the less likely they are to be suitable for donation.
With this in mind, it is unlikely that protocols surrounding death confirmation will change anytime soon.
But healthcare professionals and researchers alike are in general agreement that in this day and age, physicians have the expertise and medical equipment to effectively determine when a patient has passed.