Lazarus Effect / Phenomenon

The Lazarus effect (phenomenon) is when someone a healthcare provider has declared dead suddenly regains blood flow and appears to come back to life. This may show up as a return of pulse, an organized heart rhythm on the monitor or even improved color. Occasionally, there may appear to be limited purposeful movement. Unfortunately, most people don’t survive for long after the brief return of blood flow.

This effect gets its name from the Biblical story of Jesus bringing a man named Lazarus back from the dead. But the term is a bit misleading. The person doesn’t actually die and resurrect. Instead, there’s a delay in the return of blood flow after CPR. This is called the delayed return of spontaneous circulation (ROSC). It affects their vital signs and makes it look like they’ve died.

The medical term, autoresuscitation, is less memorable but more accurate than the “Lazarus effect.” It means your heart starts beating again without help and can send blood to your organs and tissues. This rare occurrence usually happens after CPR has ended. But there have also been reports of it occurring in people who didn’t have CPR performed on them.

Timing of events

Here’s the basic order of events that qualify a specific case as autoresuscitation:

1. A person has cardiac arrest.
2. A healthcare provider or someone else begins performing CPR.
3. The person giving CPR determines it’s not helping. They conclude the person has died.
4. A medical professional authorized to make the call declares the person clinically dead. No one performs any further medical interventions.
5. Not long after CPR stops (usually within 10 minutes), someone notices signs of life. For example, the person thought to be dead might move or start breathing. The signs must last for more than a few seconds.
6. A healthcare provider determines the person’s circulation has returned. Active medical care starts up again.

How common is the Lazarus effect?

There have been 76 cases of autoresuscitation reported in medical literature from 1982 to 2022. But most people died within hours or days. Some people survived but had brain damage. A small number of people made a full recovery.

It’s important to know that people don’t die of the Lazarus effect. Rather, they die of the cardiac arrest that led to this point. The “effect” is simply a sign that tells providers the person still has some blood flow, even though it likely won’t last for long.

Experts don’t know exactly why autoresuscitation happens. One theory suggests CPR may quickly push lots of air into your lungs, leading to hyperinflation. In other words, there’s so much air in your lungs and not enough time for you to breathe it out. This raises the pressure in your chest.

The raised pressure limits how much blood can flow in and out of your heart. When CPR stops, the pressure drops. Blood can flow into your heart again. This may cause circulation throughout your body to resume, but usually just for a short time.

Another theory involves delayed effects of medications given during CPR. When blood flow is very poor, drugs like epinephrine may take time to reach the heart. Once circulation improves even slightly, these medications can suddenly take effect and help restart the heart.

The Lazarus effect isn’t a reliable sign of survival and usually doesn’t change the outcome. Rather, it may give false hope in situations where death is likely to happen. (For the few who do survive, it’s thanks to CPR and other lifesaving measures.) For these reasons, healthcare providers take measures to keep it from occurring.

How to prevent it

The Lazarus effect can only occur after a healthcare provider declares someone clinically dead. So, providers take careful steps to lower the odds of a premature declaration of death. These include:

• Performing CPR for at least 20 minutes
• Taking steps to avoid hyperinflation during CPR (for example, by avoiding rapid or forceful breaths)
• Monitoring a person nonstop for at least 10 minutes after CPR has ended before declaring death