What Are The Potential Side Effects Of Anesthesia
Grogginess is one of the most common side effects of anesthesia. Some people will also experience nausea and/or vomiting. Typically, female patients are at a slightly higher risk, as well as patients with a history of motion sickness, Patel says.
According to the American Society of Anesthesiologists, other side effects of general anesthesia could include: a sore throat, confusion or delirium, muscle aches, chills and shivering, and itching.
Why Anesthetics Cause Prolonged Memory Loss
- University of Toronto
- Researchers have shown why anesthetics can cause long-term memory loss, a discovery that can have serious implications for post-operative patients.
Researchers at the University of Toronto’s Faculty of Medicine have shown why anesthetics can cause long-term memory loss, a discovery that can have serious implications for post-operative patients.
Until now, scientists haven’t understood why about a third of patients who undergo anesthesia and surgery experience some kind of cognitive impairment — such as memory loss — at hospital discharge. One-tenth of patients still suffer cognitive impairments three months later.
Anesthetics activate memory-loss receptors in the brain, ensuring that patients don’t remember traumatic events during surgery. Professor Beverley Orser and her team found that the activity of memory loss receptors remains high long after the drugs have left the patient’s system, sometimes for days on end.
Animal studies showed this chain reaction has long-term effects on the performance of memory-related tasks.
“Patients — and even many doctors — think anesthetics don’t have long-term consequences. Our research shows that our fundamental assumption about how these drugs work is wrong,” says Orser, a Professor in the Departments of Anesthesia and Physiology, and anesthesiologist at Sunnybrook Health Sciences Centre.
The study was published in the Journal of Clinical Investigation.
Reducing Your Risk Of Changes In Thinking Following Surgery
- Preeti Upadhyay, MBBS, MPH, Contributor
Cognition is an important function of the brain that enables us to acquire and process information, to enhance our understanding of thoughts, experiences, and our senses. Any condition that affects our ability to think, reason, memorize, or be attentive affects our cognitive ability. Some cognitive decline is a normal part of aging, but there are many things you can do to prevent or forestall cognitive changes as you age, including when planning for surgery.
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Proposed Mechanisms For Pathogenesis Of Pocd
Taken together, data from animal and human studies have fueled the hypothesisthat peripheral surgical trauma causes CNS inflammation via disruption of the blood-brain barrier , which then causes a functional disruption in neural activity, leading to POCD. Each component of this hypothesis is regulated by a variety of inflammatory mediators discussed below. This sequence of events can persist long after surgery and resolution of neuroinflammation, and can accelerate neurocognitive decline in neurocognitively frail populations.
What Studies Have Been Carried Out On The Effect Of General Anaesthetics
There have been several studies looking at how general anaesthetics affect brain cells.
Some studies have found that certain types of general anaesthetics seem to lead to increased levels of the Alzheimers hallmark toxic clumps of amyloid and tau proteins in brain cells. These proteins are thought to cause damage to brain cells in Alzheimers disease.
Some researchers suggest that some types of general anaesthetics could prevent brain cells from properly repairing damage. In the brain, damaged cells signal to nearby repair cells, which trigger the immune system to protect and heal the damage. This signalling process is thought to be altered in the brains of older people, leading to too much inflammation and causing further damage to brain cells.
Researchers also think that other factors play a role in how general anaesthetics affect the brain. For example, low levels of oxygen in the blood and lower body temperatures caused by anaesthesia may contribute towards damage to brain cells. Some studies also suggest that anaesthesia may make existing underlying dementia mechanisms worse, particularly in people at an increased genetic risk the condition.
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What Are The Effects Of Anesthesia On The Brain
Whether or not medical research can pinpoint a direct link between general anesthesia and the subsequent risk for memory issues, one fact is clear: Anesthesia drugs travel into the brain and lodge it into a state of amnesia loss of consciousness, immobility and decreased blood flow to the brain result.
Cortical Dynamics Before During And After General Anesthesia
We assessed cortical dynamics before, during, and after anesthetic exposure using local measures of permutation entropy and global measures of Lempel-Ziv complexity . Using a linear mixed model, the PE demonstrated significant differences associated with behavioral states , brain regions , and the interaction between them . As compared to the baseline condition of eyes-closed resting state, frontal PE decreased at propofol-induced loss of consciousness , further decreased during maintenance of the anesthetized state with isoflurane anesthesia , and returned to or even exceeded the baseline level just before the recovery of consciousness . Posterior PE did not show significant changes at LOC but was decreased during the maintenance phase , maintenance vs. EC1), and then returned to baseline level just before ROC . The topographic maps of PE exhibited region-specific patterns, in which frontal channels demonstrated significantly higher PE values as compared to posterior channels at the eyes-closed resting state directly after emergence .
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Will A General Anaesthetic Increase My Risk Of Developing Dementia
Whilst there is a known short-term effect of anaesthesia on memory , studies that have investigated a link between dementia risk and general anaesthetics have found mixed results.
These inconsistent findings make it difficult to definitively say whether or not general anaesthesia increases risk of dementia.
What Are The Results Of This Research
Studying the effect of general anaesthetics in the brain is difficult. Dementia can have a very slow development and there is a lack of studies that follow people for a long enough period of time.
Looking in-depth at the mechanisms underlying the effects of general anaesthetics on brain cells would require very invasive procedures and are not possible to do in people. Many studies have looked at these mechanisms in mouse and fly brains.
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Dont Exercise Right Away
We dont recommend coming out of general anesthesia and exercising right away, Patel says. Aside from the fact that anesthesia may still be in your system, there are generally limitations to movement and physical abilities post-surgery.
Depending on the operation, the surgeon should communicate any lifting restrictions, Patel says, as well as a timeline for adding exercise back in.
If you were given a local anesthetic for a minor procedure the restrictions might not be as limiting, but its a good idea to wait at least 24 hours before doing any kind of intense exercise.
Older Adults Are Having More Surgical Procedures
As our population ages and medicine and healthcare advances, more older adults are likely to develop serious conditions and undergo surgical procedures to treat or manage these conditions. Recent surveys suggest that progress in surgical techniques and control of anesthesia has increased surgical procedures in older people, with approximately 30% of all surgeries being conducted in people over the age of 70.
While advances in medicine may help people live longer, older adults are more likely to develop complications due to surgery. Some research suggests approximately one-quarter of those over 75 undergoing major surgery will develop significant cognitive decline, and about half of those people will suffer permanent brain damage.
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Therapy Used Around The World
There are no current treatments for brain fog attributed to COVID-19. But a new clinical trial at UAB is testing a proven rehabilitation method with a record of success in restoring lost function. Known as Constraint-Induced Therapy , it was developed by Edward Taub, Ph.D., University Professor in the Department of Psychology and director of the CI Therapy Research Group, in collaboration with colleagues at UAB. CI is used around the world to help patients regain limb function and language abilities after stroke.
Studies in France and the United States reveal that a third of patients hospitalized with COVID-19 have experienced memory loss and other cognitive difficulties in the months after their recovery. This brain fog can be debilitating. It feels as though I am under anesthesia, one patient said.
CI Therapy also is used to treat patients with traumatic brain injury, multiple sclerosis and cerebral palsy, and with anoxial and other brain damage in pediatric patients.
Individuals who think they can benefit are welcome to contact the project directly at 205-934-9768 or learn more about the study at uab.edu/citherapy.
Some 97% of the thousands of stroke patients who have taken part in CI Therapy have seen meaningful improvement, and the average patient uses his or her affected limb five times more post-therapy than pre-therapy.
Does The Type Of Surgery And Anesthesia Matter
Many surgical factors and techniques, blood pressure fluctuations during surgery, and longer time in surgery can adversely affect the cognitive function of older patients. Each factor affects cognitive functioning in a unique way. Younger patients tend to respond better to surgical stresses compared to older people.
Minor surgical procedures such as skin biopsies, excision of cysts, suturing of lacerations, and related procedures performed on an outpatient basis are unlikely to result in cognitive decline. However, as the complexity of a surgical procedure increases, with longer operative periods and greater exposure to more anesthesia medication, the likelihood of postoperative cognitive decline increases. This is especially true for cardiac surgery.
Studies suggest that incidence of postoperative cognitive decline is approximately 30% to 80% after cardiac surgery, while for noncardiac surgeries the prevalence is approximately 26%. While all major surgeries pose a risk for cognitive decline, cardiac surgeries have a much higher proportion of cognitive decline after surgery. The most common determinants of cognitive decline involving cardiac surgical procedures are the presence of pre-existing cognitive dysfunction and the use of bypass machines to replace the function of the heart and lungs during the surgery.
Cognitive Decline After Surgery Tied To Brains Own Immune Cells
In Mouse Study, Experimental Drug Blocks Post-Operative Memory Loss
After undergoing surgery, elderly patients often experience cloudy thinking that can last for weeks or even months. At one time researchers thought this cognitive decline might be caused by anesthesia, but mounting evidence suggests that heightened inflammation in the brain following surgery is the more likely cause.
Now a new study in mice by UC San Francisco researchers suggests that brain inflammation and cognitive decline following surgery are triggered by the brains own specialized immune cells, called microglia. Mice given an experimental oral drug that temporarily depletes microglia ahead of an operation were much less likely to fail memory tests several days after surgery, the UCSF team found, suggesting a possible new approach to preventing the condition in humans.
The study, published April 6 in JCI Insight, an online, open-access companion publication to the Journal of Clinical Investigation, was led by collaborators Suneil Koliwad, MD, PhD, assistant professor of medicine, and Mervyn Maze, MD, professor of anesthesia and perioperative care at UCSF. Koliwad has been studying microglia for several years, and Maze developed the mouse model that was used to investigate cognitive effects of surgery.
The Effects Of Surgery And Anesthesia On Memory
Major operations, like open heart and abdominal surgeries, require that the patient undergo general anesthesia. If the one going under the knife is a senior, there is a chance anesthesia will have an adverse effect on the individuals cognitive functionsat least as far as some medical researchers claim. Seniors who have experienced this phenomenon will likely require memory care after their surgery.
The earliest mention of surgeries and anesthesia prompting a host of cognitive changes is an article published in the The Lancet in 1955. The author, a surgeon and physician, noted the stark cases of patients who were cognitively normal before surgery and severely demented after their procedures.
The effects of anesthesia on the memory has a scientific namepostoperative cognitive dysfunction . Although science is hard pressed to provide sufficient scientific evidence of this phenomenon, todays medical professionals do not discount the link between surgery and resulting memory problems.
Postoperative delirium has a 60 percent chance of occurring in elderly patients who undergo surgical operations. Aging patients are increasingly at risk for developing this type of post-surgical geriatric complication. Delirium may occur immediately after surgery or surface ten years after a surgical procedure.
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Evidence From Human Studies
Although human studies rely on heterogeneous populations and are limited in scope by ethical considerations, it is possible to tease out the relative contributions of surgery vs. anesthesia to the development of POCD by comparing outcomes in patients undergoing different anesthetic regimens, including general anesthesia, neuraxial anesthesia, and sedation. Indeed, a large prospective observational study comparing coronary artery bypass grafting under general anesthesia, hip replacement under spinal anesthesia, and percutaneous coronary angiography under sedation showed no difference in POCD rates between groups . This result was especially interesting as rates of POCD were long thought to be higher in cardiac surgery due to the inflammation associated with CPB . These results have been supported by prospective observational studies showing no difference in POCD between spinal vs. general anesthesia for orthopedic surgery . Moreover, a large systematic review was unable to demonstrate a clear connection between general anesthesia and POCD , although the majority of studies examined were underpowered and used variable methodologies. As in animal studies, it has even been proposed that volatile anesthesia may be protective in the setting of ischemic organ damage, ultimately mitigating POCD from organ ischemia .
Table 2. Relevant clinical studies on etiology of POCD.
Key Points About Vascular Dementia
- Vascular dementia is a disorder characterized by damaged brain tissue due to a lack of blood flow. Causes can include blood clots, ruptured blood vessels, or narrowing or hardening of blood vessels that supply the brain.
- Symptoms can include problems with memory and concentration, confusion, changes in personality and behavior, loss of speech and language skills, and sometimes physical symptoms such as weakness or tremors.
- Vascular dementia tends to progress over time. Treatments can’t cure the disease, but lifestyle changes and medicines to treat underlying causes might help slow its progress.
- Surgical procedures to improve blood flow to the brain can also be helpful. Other medicines might slow the progression of dementia or help with some of the symptoms it can cause.
- A person with vascular dementia may eventually need full-time nursing care or to stay in a long-term care facility.
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Does Anesthesia Kill Brain Cells
It has long been known that a single exposure to anesthesia leads to widespread neuronal cell death throughout the brain in very young animals. The results confirm their previous findings that isoflurane exposure greatly increases caspase expression and cell death in these immature, developing neurons.
How Do You Reverse Memory Loss After Anesthesia
The new findings strongly suggest that the alpha-5 GABA type A receptors are necessary for the development of anesthesia-related memory deficits. They also suggest that drugs to block those receptors are a plausible strategy for reversing memory deficits after general anesthesia, the researchers write.
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Anesthesia Surgery Linked To Subtle Decline In Memory And Thinking In Older Adults Mayo Study Finds
ROCHESTER, Minn. In adults over 70, exposure to general anesthesia and surgery is associated with a subtle decline in memory and thinking skills, according to new Mayo Clinic research. The study analyzed nearly 2,000 participants in the Mayo Clinic Study of Aging and found that exposure to anesthesia after age 70 was linked to long-term changes in brain function. The results appear in the British Journal of Anaesthesia.
Although the decline in brain function was small, it could be meaningful for individuals with already low cognitive function or pre-existing mild cognitive impairment who are considering surgery with general anesthesia, the researchers note. In older adults with borderline cognitive reserve that is not yet clinically obvious, exposure to anesthesia and surgery may unmask underlying problems with memory and thinking.
The link between exposure to anesthesia and surgery, and cognitive decline in older adults has been debated for many years. Animal studies have suggested that exposure to inhaled anesthetics may be related to brain changes linked to Alzheimers disease however, most previous studies in humans have not consistently shown association between anesthesia and impaired brain function.
The authors emphasized that it is not possible to determine whether anesthesia, surgery or the underlying conditions necessitating surgery caused the decline.
Does Having Surgery Increase My Dementia Risk
It is difficult to say from observational studies what part of the surgery has led to a particular complication. Some say that the effect on memory could actually be caused by the surgery itself and not the anaesthetic.
Surgery tends to carry higher risks of complications for older people, such as infection. One reason for this that an older body may be less able to protect itself from and repair damage. Doctors sometimes measure this as frailty.
Studies have shown that older patients with higher frailty are at higher risk of complications, short term thinking and memory problems, and longer stays in hospital after surgery.Some researchers think that cell damage from surgery is more likely to trigger too much inflammation in older brains than general anaesthetics are. There is some evidence that surgery can result in inflammation, which is associated with cognitive decline. The exact mechanism causing this is not well understood yet.
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