Chewing gum while fasting before surgery is safe, study finds

It is well known that patients should avoid eating and drinking before surgery to help prevent complications while under anesthesia. But is it safe to chew gum? Although chewing gum significantly increases the volume of liquids in the stomach, it is safe to administer sedatives or anesthesia to patients who have chewed gum while fasting before surgery, reports a new study presented at the ANESTHESIOLOGY™ 2014 annual meeting.

“The effect of chewing gum on fasting has been a subject of debate, and unsuspecting patients who chew gum before surgery may face cancellation or delay of their procedure,” said Basavana Goudra, M.D., lead author and assistant professor of clinical anesthesiology and critical care at Perelman School of Medicine at the University of Pennsylvania, Philadelphia. “We found that although chewing gum before surgery increases the production of saliva and thus the volume of stomach liquids, it does not affect the level of stomach acidity in a way that would elevate the risk of complications.”

Preoperative fasting guidelines recommended by the American Society of Anesthesiologists® (ASA®) do not allow eating or drinking, for a specific period of time before anesthesia is administered due to the risk of pulmonary aspiration, a serious complication in which stomach contents are drawn into the respiratory tract during breathing. Fasting helps prevent pulmonary aspiration by keeping stomach contents and acidity levels low. If stomach contents include very high acidity levels, even a small amount can cause life-threatening pulmonary aspiration. Although the ASA guidelines do not explicitly mention chewing gum, it is typically considered a non-clear liquid and not allowed before surgery.

In the study, 67 patients scheduled to undergo gastrointestinal endoscopic procedures were randomly divided into two groups. Thirty-four patients were allowed to chew gum until just before the start of their procedure, while 33 patients continued to follow the recommended fasting guidelines. There was no limit on the type, number of gums chewed or duration of chewing. After sedation and endoscope insertion, stomach contents were suctioned and volume and pH (acidity) were measured.

The mean gastric volume, or total amount of liquid in the stomach, was statistically higher in patients who chewed gum before their procedure (13ml) versus those who did not (6ml). However, there was no statistically significant difference in pH values.

“While we wouldn’t actively encourage gum chewing in patients presenting for procedures involving anesthesia, in the absence of other aspiration risk factors, patients who inadvertently chew gum should not face cancellation or delay of a surgery or procedure with anesthesia,” said Dr. Goudra.

http://www.medicalnewstoday.com/releases/283539.php

Picture courtesy of www.healthtap.com

 

Sleep apnea screening before surgery: treatment helps reduce risk of cardiovascular complications by more than half

Scheduled for surgery? New research suggests that you may want to get screened and treated for obstructive sleep apnea (OSA) before going under the knife. According to a first-of-its-kind study in the October issue of Anesthesiology,the official medical journal of the American Society of Anesthesiologists® (ASA®), patients with OSA who are diagnosed and treated for the condition prior to surgery are less likely to develop serious cardiovascular complications such as cardiac arrest or shock.

“OSA is a common disorder that affects millions and is associated with an increased risk of surgical complications, but the condition often goes unrecognized,” said Thomas Mutter, M.D., lead author, department of anesthesia and perioperative medicine, University of Manitoba, Winnipeg, Canada. “As many as 25 percent of surgical patients may have OSA, but the vast majority of these patients aren’t treated or don’t know they have the disorder.”

OSA causes the soft tissue in the rear of the throat to narrow and repeatedly close during sleep. The brain responds to each of these “apnea events” by waking the person in order to resume breathing. Since apnea events can happen hundreds of times per night, sleep becomes broken and ineffective and can lead to serious health problems if undetected. Those who are overweight or have high blood pressure are predisposed to developing OSA. It tends to occur in men but women can also develop OSA. Symptoms of apnea may include: heavy snoring, pauses in breathing during sleep and excessive sleepiness during the day.

The study compared postoperative outcomes in 4,211 patients with OSA, who were diagnosed by sleep study either before or after surgery, with a matched control group of patients who did not have the condition. Those who were diagnosed with OSA prior to surgery were prescribed treatment with continuous positive airway pressure (CPAP) therapy. CPAP keeps a patient’s airway open by gently delivering pressurized air through a face mask.

The study found that although patients with untreated OSA were at an increased risk of developing cardiovascular complications, patients who were diagnosed and treated with CPAP therapy before surgery were less than half as likely to experience cardiovascular complications such as cardiac arrest or shock.

Additionally, researchers found that respiratory complications were twice as likely to occur in patients with OSA, compared to patients without the condition, regardless of when patients were diagnosed or if CPAP therapy was prescribed.

http://www.medicalnewstoday.com/releases/282959.php

 

Handheld scanner could make brain tumor removal more complete, reducing recurrence

Cancerous brain tumors are notorious for growing back despite surgical attempts to remove them – and for leading to a dire prognosis for patients. But scientists are developing a new way to try to root out malignant cells during surgery so fewer or none get left behind to form new tumors. The method, reported in the journal ACS Nano, could someday vastly improve the outlook for patients.

Moritz F. Kircher and colleagues at Memorial Sloan Kettering Cancer Center point out that malignant brain tumors, particularly the kind known as glioblastoma multiforme (GBM), are among the toughest to beat. Although relatively rare, GBM is highly aggressive, and its cells multiply rapidly. Surgical removal is one of the main weapons doctors have to treat brain tumors. The problem is that currently, there’s no way to know if they have taken out all of the cancerous cells. And removing extra material “just in case” isn’t a good option in the brain, which controls so many critical processes. The techniques surgeons have at their disposal today are not accurate enough to identify all the cells that need to be excised. So Kircher’s team decided to develop a new method to fill that gap.

The researchers used a handheld device resembling a laser pointer that can detect “Raman nanoprobes” with very high accuracy. These nanoprobes are injected the day prior to the operation and go specifically to tumor cells, and not to normal brain cells. Using a handheld Raman scanner in a mouse model that mimics human GBM, the researchers successfully identified and removed all malignant cells in the rodents’ brains. Also, because the technique involves steps that have already made it to human testing for other purposes, the researchers conclude that it has the potential to move readily into clinical trials. Surgeons might be able to use the device in the future to treat other types of brain cancer, they say.

The authors acknowledge funding from the National Institutes of Health.

http://www.medicalnewstoday.com/releases/282033.php

 

Many nervous system mechanisms shared in human and animal parenting

Strong evidence now shows that human and animal parenting share many nervous system mechanisms. This is the conclusion of Yerkes National Primate Research Center researchers Larry Young, PhD, and James Rilling, PhD, in their review article about the biology of mammalian parenting, published in the journal Science. Better understanding this biology could lead to improved social development, benefitting generations of humans and animals to come.

In their article, Young and Rilling review the biological mechanisms governing a shift in mammals’ parental motivation that begins with aversion and transforms into irresistible attraction after giving birth. They say the same molecules that prepare the uterus for pregnancy, stimulate milk production and initiate labor also activate specific neural pathways to motivate parents to nurture, bond with and protect their offspring.

According to Young, “We have learned a tremendous amount about the specific hormonal and brain mechanisms regulating parental behavior and how parental nurturing influences the development of the offspring brain by using animal models, and many of these same mechanisms influence human parenting behavior as well.”

Young is division chief of Behavioral Neuroscience and Psychiatric Disorders at the Yerkes Research Center, director of the Center for Translational Social Neuroscience at Emory, a William P. Timmie professor in the Department of Psychiatry at Emory’s School of Medicine and author of The Chemistry Between Us: Love, Sex and the Science of Attraction, which also summarizes the parallels between brain mechanisms regulating sexual and parenting behaviors in animals and humans.

Rilling, who is a Yerkes researcher and an associate professor in Emory’s Department of Anthropology, adds, “The human brain has mechanisms in place to support parent-child bonding, and when functioning properly, these mechanisms facilitate the development of secure attachment and sound mental health that is transmitted across generations.”

The researchers divided their review into nine categories, including neural correlates of human parental care, two specific to parenting and oxytocin, two focused specifically on paternal caregiving by fathers and two related to the effect of parenting on social development. Examples within these categories include that the frustration inconsolable infant crying induces is a risk factor for infant abuse, highlighting the importance of emotion regulation for sensitive parenting; that oxytocin affects maternal motivation and paternal behaviors essential for nurturing, bonding and defending the offspring; that testosterone may interfere with parenting effort; and that variation in parental nurturing can affect brain development, thus affecting future social behaviors.

“With this comprehensive review, we can see nervous system correlations across species that result in positive and negative parental care,” says Young. “This information is critical to further studying social development in order to facilitate positive parental behaviors that will benefit generations to come,” he continues.

Established in 1930, the Yerkes National Primate Research Center paved the way for what has become the National Institutes of Health-funded National Primate Research Center (NPRC) program. For more than eight decades, the Yerkes Research Center has been dedicated to conducting essential basic science and translational research to advance scientific understanding and to improve human health and well-being. Today, the Yerkes Research Center is one of only eight NPRCs. The center provides leadership, training and resources to foster scientific creativity, collaboration and discoveries, and research at the center is grounded in scientific integrity, expert knowledge, respect for colleagues, an open exchange of ideas and compassionate, quality animal care.

Within the fields of microbiology and immunology, neurologic diseases, neuropharmacology, behavioral, cognitive and developmental neuroscience, and psychiatric disorders, the center’s research programs are seeking ways to: develop vaccines for infectious and noninfectious diseases; understand the basic neurobiology and genetics of social behavior and develop new treatment strategies for improving social functioning in social disorders such as autism; interpret brain activity through imaging; increase understanding of progressive illnesses such as Alzheimer’s and Parkinson’s diseases; unlock the secrets of memory; treat drug addiction; determine how the interaction between genetics and society shape who we are; and advance knowledge about the evolutionary links between biology and behavior.

http://www.medicalnewstoday.com/releases/281121.php

 

Concussions from top-of-head impact ‘more severe’

As we head into the start of the new school year, many young people will begin signing up for the football team. Though team sports are a great way for kids to boost their self-esteem and increase physical activity, there are certain risks involved with contact sports, including concussions. Now, a recent study from the American Academy of Pediatrics investigates how the location of impact could affect concussion severity.

Prior to this study, published in the journalPediatrics, very little research had focused on how location of impact on the head could yield differentconcussion outcomes.

According to the Centers for Disease Control and Prevention (CDC), a concussion is a traumatic brain injury (TBI) that is the result of a bump, blow or jolt to the head that can change how the brain normally works.

To investigate further, researchers used data from the National High School Sports-Related Injury Surveillance Study to calculate rates and circumstances of concussions that occurred during football as a result of player-to-player collisions.

The team observed that most concussions of this type (44.7%) occurred on the front of the head, while 22.3% occurred on the side of the head. Based on where the impact occurred, the number and type of symptoms, symptom resolution time, and length of time before returning to play did not vary significantly.

But the data revealed that more football players whose concussions resulted from top-of-head impacts lost consciousness than those whose impacts were located elsewhere on the head.

In detail, 8% of players with top-of-head concussions experienced loss of consciousness, compared with only 3.5% of those with impacts on other areas.

‘Heads up’ tackling technique is safest

The researchers say top-of-head injuries were more likely to occur when players had their heads down during impact, which highlights the need for safe tackling techniques in football.

USA Football, the official youth football partner of the National Football League (NFL), have a “Heads Up Football” campaign, which seeks to “create change and address the complex challenges of player health and safety in youth and high school football.”

The organization has put together a video detailing the safest way to tackle:

Commenting on the program, Dr. Gerard A. Gioia, pediatric neuropsychologist from Children’s National Medical Center and associate professor at George Washington University School of Medicine in Washington, DC, says:

“This overall approach and the specific techniques within the program are exactly the next steps we need to take to improve head safety in tackle football. The effort to teach effective, yet safe tackling and blocking techniques at the earliest youth levels can only have positive downstream benefits for our players at the high school, college and professional levels.”

Concussions ‘are not a bruise to the brain’

According to the CDC, emergency departments in the US treat 173,285 sports- and recreation-related TBIs each year. This includes concussions among adults and adolescents from birth to 19 years old.

They note that children and teens are more likely to experience a concussion and take longer to recover from such an injury, compared with adults. Unlike a broken bone or other injuries that can be felt with the hand, a concussion disrupts how the brain actually works.

“It is not a ‘bruise to the brain,'” say the CDC.

Though symptoms of concussion usually show up directly after the injury, the full effect may not be immediately noticeable, so coaches and parents should be aware of the signs and symptoms, and should not encourage young athletes to keep playing after a blow to the head.

The CDC have created free tools for coaches, parents, athletes and health care professionals, which provide vital information on how to prevent, recognize and respond to a concussion. For more information, visit the CDC’s Injury Prevention & Control website.

Earlier this year, Medical News Today reported on a study that suggested football helmets may do little to protect players from concussion. Results of that study revealed that football helmets only reduce risk of TBIs by 20%, compared with not wearing a helmet.

Written by Marie Ellis

http://www.medicalnewstoday.com/articles/280869.php

The disruptive effects of anesthesia on brain cell connections are likely temporary

A study of juvenile rat brain cells suggests that the effects of a commonly used anesthetic drug on the connections between brain cells are temporary.

Hippocampal cells with neuron in green showing hundreds of the small protrusions known as dendritic spines. The dendrites of other dendrites are labeled in blue, and adjacent glial cells are shown in red.
Credit:. Barbara Calabrese, UC San Diego

The study, published in this week’s issue of the journal PLOS ONE, was conducted by biologists at the University of California, San Diego and Weill Cornell Medical College in New York in response to concerns, arising from multiple studies on humans over the past decade, that exposing children to general anesthetics may increase their susceptibility to long-term cognitive and behavioral deficits, such as learning disabilities.

An estimated six million children, including 1.5 million infants, undergo surgery in the United States requiring general anesthesia each year and a least two large-scale clinical studies are now underway to determine the potential risks to children and adults.

Hippocampal neuron from rodent brain with dendrites shown in blue. The hundreds of tiny magenta, green and white dots are the dendritic spines of excitatory synapses.
Credit: Barbara Calabrese, UC San Diego

“Since these procedures are unavoidable in most cases, it’s important to understand the mechanisms associated with the potentially toxic effects of anesthetics on the developing brain, and on the adult brain as well,” said Shelley Halpain, a professor of biology at UC San Diego and the Sanford Consortium for Regenerative Medicine, who co-headed the investigation. “Because the clinical studies haven’t been completed, preclinical studies, such as ours, are needed to define the effects of various anesthetics on brain structure and function.”

“There is concern now about cognitive dysfunction from surgery and anesthesia – how much these effects are either permanent or slowly reversible is very controversial,” said Hugh Hemmings, Jr., chair of anesthesiology at Weill Cornell and the study’s other senior author. “It has been suggested recently that some of the effects of anesthesia may be more lasting than previously thought. It is not clear whether the residual effects after an operation are due to the surgery itself, or the hospitalization and attendant trauma, medications and stress – or a combination of these issues.”

However, he added, “There is evidence that some of the delayed or persistent cognitive effects after surgery are not primarily due to anesthesia itself, but more importantly to brain inflammation resulting from the surgery. But this is not yet clear.”

The team of biologists examined one of the most commonly used general anesthetics, a derivative of ether called “isoflurane” used to maintain anesthesia during surgery.

“Previous studies in cultured neurons and in the intact brains of rodents provided evidence suggesting that exposure to anesthetics might render neurons more susceptible to cell death through a process called ‘apoptosis’,” said Halpain. “While overt cell death could certainly be one way to explain any long-lasting neurocognitive consequences of general anesthesia, we hypothesized that there could be other cellular mechanisms that disrupt neural circuits without inducing cell death per se.”

One such mechanism, she added, is known as “synaptotoxicity.” In this mechanism of neural-circuit disruption, the “synapses,” or junctions between neurons, become weakened or shrink away due to some factor that injures the neurons locally along their axons (the long processes of neurons that transmit signals) and dendrites (the threadlike extensions of neurons that receive nerve signals) without inducing the neurons themselves to die.

In the experiments at UC San Diego headed by Jimcy Platholi, a postdoctoral researcher in Halpain’s lab who is now at Weill Cornell, the scientists used neurons from embryonic rats taken from the hippocampus, a part of the mammalian forebrain essential for encoding newly acquired memories and ensuring that short-term memories are converted into long-term memories. The researchers cultured these brain cells in a laboratory dish for three weeks, allowing the neurons time to mature and to develop a dense network of synaptic connections and “dendritic spines” – specialized structures that protrude from the dendrites and are essential mediators of activity throughout neural networks.

“Evidence from animal studies indicates that new dendritic spines emerge and existing spines expand in size during learning and memory,” explained Halpain. “Therefore, the overall numbers and size of dendritic spines can profoundly impact the strength of neural networks. Since neural network activity underlies all brain function, changes in dendritic spine number and shape can influence cognition and behavior.”

Using neurons in culture, rather than intact animal brains, allowed the biologists to take images of the synapses at high spatial resolution using techniques called fluorescence light microscopy and confocal imaging. They also used time-lapse microscopy to observe structural changes in individual dendritic spines during exposure to isoflurane. Karl Herold, a research associate in the Hemmings laboratory and a co-author of the study, performed some of the image analysis.

“Imaging of human brain synapses at this level of detail is impossible with today’s technology and it remains very challenging even in laboratory rodents,” said Halpain. “It was important that we performed our study using rodent neurons in a culture dish, so that we could really drill down into the subcellular and molecular details of how anesthetics work.”

The researchers wondered whether brief exposure to isoflurane would alter the numbers and size of dendritic spines, so they applied the anesthetic to the cultured rat cells at concentrations and durations (up to 60 minutes) that are frequently used during surgery.

“We observed detectable decreases in dendritic spine numbers and shape within as little as 10 minutes,” said Halpain. “However this spine loss and shrinkage was reversible after the anesthetic was washed out of the culture.”

“Our study was reassuring in the sense that the effects are not irreversible and this fits in with known clinical effects,” said Hemmings. “For the most part, we find that the effects are reversible.”

“We clearly see an effect – a very marked effect on the dendritic spines – from use of this drug that was reversible, suggesting that it is not a toxic effect, but something more relevant to the pharmacological actions of the drug,” he added. “Connecting what we found to the cognitive effects of isoflurane will require much more detailed analysis.”

The team plans to follow up its study with future experiments to probe the molecular mechanisms and long-lasting consequences of isoflurane’s effects on neuron synapses and examine other commonly-used anesthetics for surgery.

http://www.medicalnewstoday.com/releases/280259.php