Brain Recovery After Anesthesia

Each year, more than 40 million people undergo surgical procedures which require general anesthesia.  For those who are having surgery there are many concerns regarding undergoing anesthesia and these issues are very common.  The two biggest questions anyone has is “Will I wake up after surgery?”, and the other is “Will I wake up during surgery?”  While surgical procedures are not without risk to the individual, it is reassuring to know that anesthesia has improved dramatically and has become much safer in recent years.

When was anesthesia first used?

During the 1940’s, for every one million patients who were operated on under total anesthesia, 640 would die.  However, by the ending of the 1980’s, the fatality rate was significantly diminished to four deaths per every 1-million people operated on under general anesthesia.  The improvements in the fatality rates associated with general anesthesia were due to an improvement in medical training and the incorporation of modern safety protocols.

What happens during anesthesia exposure?

There have been reports of people never quite being the same after undergoing a surgical procedure requiring general anesthesia. Other individuals report personal experiences after undergoing anesthesia which includes a reduced ability to concentrate, reduced attention span and other cognitive issues.  

What is Postoperative Cognitive Disorder?

People report many different mental changes after going through an operation under anesthesia and these issues can be very difficult to evaluate and measure objectively.  The cognitive impact of anesthesia is all bundled together into a term known as Postoperative Cognitive Disorder (POCD).  The condition is defined as the mental process of knowledge and it includes judgment, awareness, reasoning and perception.  People with POCD report the following symptoms:

• Reduced ability to perform mathematical tasks
• Easily tired and fatigued
• Memory dysfunction
• Lack of an ability to concentrate

Is Someone really sleeping when under anesthesia?

One of the greatest mysteries of using anesthesia during surgery is how someone can be temporarily rendered completely unresponsive during a surgical procedure and then wake up when it’s over.  

See Also: Should You Ask For Anesthesia When You Have A Colonoscopy?

New research findings have hinted the human must pass through a variety of different steps on the path back to becoming conscious after anesthesia.  Dr. Andrew Hudson, an assistant professor of anesthesiology at the David Geffen School of Medicine, UCLA, and his colleagues provide vital clues about the process the brain uses to come back to consciousness after anesthesia. 

Researchers studying rodent brains under anesthesia found brain activity occurred in distinct clusters or clumps and that the brain did not jump between all these phases uniformly.  The patterns the brain goes through while recovering from anesthesia will depend on how much anesthesia the patient was given and the brain would spontaneously jump from one pattern of activity to another.

Are We Actually “Put To Sleep” Under Anesthesia?

When people are put under anesthesia, it is often called “going to sleep” and now according to new research, that is exactly what happens.  New evidence in a study done on mice was reported in the Current Biology publication in October of 2012.  The study found the drugs didn’t just turn off wakefulness, but it also turned on sleep circuits in the brain.

Doctors and researchers have long wondered just how anesthesia works on the human brain and the differences between anesthetic induced sleep natural sleep.  While even the deepest sleeper can be roused using various types of stimulus, someone under anesthesia will maintain a steady slumber state even in spite of all the painful and grueling physical assaults physical surgery can bring.

In the study, the researcher team focused on a particular portion of the brain, deep inside the hypothalamus. In this area, there is an increase in activity once a subject goes to sleep.  Through using a combination of electronic recording and other methods, scientists found that the anesthesia drug isoflurane boosted activity in this area of the brain.  Further evidence shows neuron function in that area of the brain becomes more resistant during exposure to anesthesia.

These findings are not only very important for clinical reasons, but could also go a long way in providing important information about anesthesia.  Anesthetics are given to about 230 million people each year all over the world and yet, there is still more information to be learned. 

Investigative researchers from Massachusetts General Hospital and the Massachusetts Institute of Technology have identified a pattern of brain activity which signals the precise moment someone loses consciousness when under general anesthesia.  Though the study only involved the use of propofol, researchers believe the findings can be applied to other types of general anesthesia drugs and may lead to better monitoring of anesthetized patients.

Finding out how anesthetics induce unconsciousness is a major scientific mystery, so finding out the information is extremely important because it shows how the mechanism of action in propofol works.  

However, the recent study measured the activity on both single neurons and neuronal networks in three patients who had electrodes installed in their brain to help diagnose epilepsy.  During the onset of the surgical procedure to remove the electrodes, patients were requested to press a button when they heard a distinct tone which was generated every four or five seconds.  When a patient failed to respond three simultaneous times, the five second period defined by those tones was outlined as the time consciousness was achieved.

See Also: Report Says U.S. Doctors Prescribe Too Much Drugs And Don't Think About Alternative Treatments

In Conclusion

The findings of all of these research studies show the human brain undergoes some profound and complex changes when under the influence of anesthesia.  Having as much information about how anesthesia influences the human brain will help anesthesiologists develop better and safer ways of methods of anesthetizing patients and thus reducing the mortality rates for people undergoing surgical procedures which require anesthesia.