Study shows different anesthetics affects sleep cycles in different ways

October 4, 2011, University of Pennsylvania School of Medicine

(Medical Xpress) -- In the ongoing quest to find the exact way that anesthetics interact with the central nervous system, anesthesiology researchers have been examining whether the state induced by anesthetics resembles natural sleep. One way to measure this is to determine whether undergoing general anesthesia results in a sleep debt for patients. Previous research has shown that the injected anesthetic propofol does not cause a sleep deficit. Now, researchers at the Perelman School of Medicine at the University of Pennsylvania have shown in animal models that another group of anesthetics, commonly used in the operating room, do not substitute for natural sleep and may cause complications for surgery patients already at-risk for sleep-related issues. The new research is published in the October 2011 issue of the journal Anesthesiology.

"Recent studies have repeatedly found a similarity between the state induced by general anesthesia and the deepest stages of NREM sleep, yet we all realize that the states are not identical. Even the deepest sleeper can be awakened by environmental stimuli whereas the anesthetized patient does not reawaken until delivery of are terminated," said Max B. Kelz, MD, PhD, assistant professor of Anesthesiology and Critical Care and the study's lead author. "In contrast to previous research done with propofol, our study found that volatile inhaled anesthetics cause a REM sleep deficit, suggesting that this group of anesthetics do not fully substitute for natural sleep, which consists of both NREM and REM sleep."

Sleep is prompted by of activity in the brain and consists of two basic states: (REM) sleep and non-rapid eye movement (NREM) sleep. During sleep, the body cycles between non-REM and REM sleep. Typically, people begin the sleep cycle with a period of non-REM sleep followed by a very short period of REM sleep.

In the current study, researchers used and to assess NREM and REM sleep patterns in mice before and after a 6-hour exposure to the inhaled anesthetics isoflurane, sevoflurane, and halothane. They found that the mice in all three groups exhibited a significant doubling of REM sleep after the anesthetics had worn off, similar to the effects of significant natural sleep deprivation. Only one anesthetic agent, halothane, also caused an additional NREM sleep debt.
The results suggest that the brain is still able to track time elapsed under general anesthesia, recognizing that the body is not truly "asleep" under different forms of anesthesia and therefore still needs sleep for homeostasis.

"Our study demonstrates that the inhaled anesthetics appear to inhibit the neural systems required for REM sleep as well as cortical arousal. In ongoing and future studies, we are testing the idea that anesthetic-induced unconsciousness could simply be a NREM sleep-like state from which the anesthetized patient cannot be awakened," said Dr. Kelz. "Ultimately, if we could discover a novel anesthetic compound that produced a state of restorative NREM sleep from which the patient could not be awakened until the drug was removed, we believe we would be able to limit the side effects of existing anesthetic drugs."

The researchers caution that it is too early to make connections to current practices in humans, but these preliminary findings suggest that a study in humans is merited. "Our findings would suggest that these volatile anesthetics act in a fundamentally different way than the anesthetic propofol," said Dr. Kelz. "As such, propofol might be a better choice for selective groups of patients, such as those with sleep apnea in whom dangerous complications of apnea (failure to breathe), hypoxia (low blood oxygen levels), and cardiac arrhythmias are known to occur more frequently during ," Dr. Kelz said.

Explore further: Inducing non-REM sleep in mice by novel optogenetical control technique

More information:

Related Stories

Inducing non-REM sleep in mice by novel optogenetical control technique

July 20, 2011
Recently, optogenetics, which controls the activity of neuron using the light-activated protein, has been getting a lot of attention. This light-activated protein works like a switch of neurons by sensing specific color of ...

Recommended for you

Synthetic cannabinoid reduces sleep apnea

November 29, 2017
A synthetic version of a molecule found in the cannabis plant was safe and effective in treating obstructive sleep apnea in the first large, multi-site study of a drug for the sleep disorder funded by the National Institutes ...

Sleeping through the snoring: Researchers identify neurons that rouse the brain to breathe

November 2, 2017
A common and potentially serious sleep disorder, obstructive sleep apnea affects at least one quarter of U.S. adults and is linked to increased risk of diabetes, obesity and cardiovascular disease. In a paper published today ...

Remede system approved for sleep apnea

October 9, 2017
(HealthDay)—The Remede sleep system, an implanted device that treats central sleep apnea by activating a nerve that sends signals to the diaphragm to stimulate breathing, has been approved by the U.S. Food and Drug Administration.

Inflammation may precede sleep apnea, could be treatment target

September 1, 2017
Inflammation is traditionally thought of as a symptom of sleep apnea, but it might actually precede the disorder, potentially opening the door for new ways to treat and predict sleep apnea, according to researchers.

More evidence: Untreated sleep apnea shown to raise metabolic and cardiovascular stress

August 31, 2017
Sleep apnea, left untreated for even a few days, can increase blood sugar and fat levels, stress hormones and blood pressure, according to a new study of sleeping subjects. A report of the study's findings, published in the ...

Sleep patterns contribute to racial differences in disease risk

August 18, 2017
Poor sleep patterns could explain, in part, the differences in the risk of cardiometabolic disease between African-Americans and European-Americans, according to a new study published in Proceedings of the National Academy ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.