Medically Induced Coma

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What is a medically induced coma?

A medically induced coma uses drugs to achieve a deep state of brain inactivity. It is a deep, but reversible unconsciousness that doctors purposely induce. Medically induced coma vs. sedation for general anesthesia differs in the level of unconsciousness. In fact, general anesthesia is a type of medically induced coma. However, what most people think of as a medically induced coma serves a different purpose than general anesthesia. 

The goal of a medically induced coma is to reach a level of sedation called ‘burst suppression.’ In this state, the brain is completely quiet for several seconds, alternating with very short bursts of activity. The period when the brain is quiet gives it vital time to rest and heal. The goal of general anesthesia, on the other hand, is to keep the brain unaware of and unable to feel or respond to pain.

(A common name for medically induced coma is drug-induced coma, but this can be confused with comas caused by the inappropriate use of illicit drugs or a drug reaction, which is a coma due to drug intoxication.)


Why is medically induced coma performed?

The most common reasons for medically induced coma involve traumatic brain injuries. These brain injuries often result in significant swelling of the brain. The swelling puts pressure on the brain. This reduces blood flow and oxygen supply to the brain, which can damage brain tissue. Inducing a coma allows the brain to rest. It decreases the brain’s electrical activity and metabolic rate. Ultimately, this state helps decrease brain swelling and protects the brain from further damage. Stroke, status epilepticus, and drug overdose are other potential reasons for medically induced coma.

A medically induced coma is not a common procedure. It is usually a last resort when other options for reducing brain swelling have failed. Doctors usually try medicines, such as steroids or diuretics, first.


Who performs medically induced coma?

An anesthesiologist will start a medically induced coma. An anesthesiologist specializes in relieving pain and providing total medical care for patients before, during and after surgery. They also care for patients outside the surgery department in areas such as intensive care units (ICUs) and pain clinics.

Once the medically induced coma is underway, ICU staff will closely monitor brain activity and vital signs. Staff includes doctors, nurses, and other critical care healthcare providers.


How is medically induced coma performed?

Medically induced comas are ICU procedures. ICUs have the necessary equipment to support the airway and monitor heart rate, blood pressure, and respiration. This support and monitoring is necessary for the entire time someone is in a medically induced coma.

An anesthesiologist will give drugs to induce the coma. Common agents include propofol, pentobarbital and thiopental. These are powerful anesthetics that will take the brain to a state of deep unconsciousness. 

An EEG (electroencephalograph) allows the doctor to monitor brain activity. Once the brain’s activity reaches the goal level, a machine will continue to deliver precise doses of anesthetic. ICU staff will continually monitor the EEG and adjust the dose as necessary to maintain the target brain activity level. While the person is in a medically induced coma, they will be unresponsive.

Once doctors decide it is safe, an anesthesiologist will reverse the process and bring the person out of the coma. In most cases, medically induced comas are only necessary for a short period of time. Doctors typically use the procedure for a couple of days or for as long as two weeks. It is rare for medically induced comas to last for longer periods.


What are the risks and potential complications of medically induced coma?

Complications that can occur from medically induced coma include:

Reducing the risk of complications

It is not always possible to reduce the risk of complications with medically induced coma. What’s more, it can be difficult to separate complications of medically induced coma from complications of the brain injury itself. Doctors use medically induced coma as a last resort, when the benefit outweighs the possible risks.


What to Expect Afterwards

When doctors see improvements in a person’s condition, they will bring them out of the medically induced coma. The process is the reverse of inducing it. Doctors gradually withdraw the drugs while monitoring brain activity and other vital signs.   

How long will it take to recover?

The length of time it takes to recover from a medically induced coma depends on several factors. This includes the underlying brain injury and how long the coma lasted. In general, the longer the coma is necessary, the more time it will take to regain functions.

Is there pain after regaining consciousness?

A medically induced coma eliminates pain. However, the underlying brain injury and other treatments may involve pain and discomfort once consciousness returns.

How might a medically induced coma affect the individual’s everyday life?

A medically induced coma is one option doctors may use to protect the brain after serious trauma and help it heal. The ultimate effect on everyday life largely depends on the extent of brain damage from the trauma. It is possible to have lingering disability due to the underlying brain trauma.


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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2019 Dec 18
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  4. Medically Induced Coma: Inducing a State of Profound Unconsciousness. RN.com. https://www.rn.com/nursing-news/medically-induced-coma-inducing-state-of-profound-unconsciousness/ 
  5. New Way to Monitor Induced Comas. Massachusetts Institute of Technology. http://news.mit.edu/2013/a-new-way-to-monitor-induced-comas-1031 
  6. Shanechi MM, Chemali JJ, Liberman M, et al. A brain-machine interface for control of medically-induced coma. PLoS Comput Biol. 2013;9(10):e1003284. 
  7. What Is a Drug-Induced Coma? American Addiction Centers. https://americanaddictioncenters.org/health-complications-addiction/induced-coma 
  8. What Is a Medically Induced Coma? Live Science. https://www.livescience.com/39483-what-is-a-medically-induced-coma.html 
  9. What Is a Medically Induced Coma and Why Is It Used? Scientific American. https://www.scientificamerican.com/article/what-is-a-medically-induced-coma/ 


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