THE OBESE PATIENT AND ANESTHESIA

Perhaps you’re overweight and you wish you weren’t.

Your anesthesiologist wishes the same thing.

Obese patients make anesthesiologists’ work more arduous.  Obese patients, especially morbidly obese and super obese patients, are at increased risk when they need surgery.  Let’s look at the reasons why.

Two hundred million Americans, or 65% of the U.S. adult population, are overweight or obese. Obesity is second only to smoking as a preventable cause of death (Conway B, Rene A. Obesity as a disease: No lightweight matter.  Obes Rev  2004; 5:145-151).

The body mass index (BMI) has become the most widely applied classification tool used to assess individual weight status.  BMI is defined as the patient’s weight, measured in kilograms, divided by the square of the patient’s height, measured in meters.

A normal BMI is between 18.5 and 24.9.  Patients are considered to be overweight with a BMI between 25 and 29.9 obese with a BMI between 30 and 39.9, morbidly obese between 40 and 49.9, and super obese at greater than 50.

Morbid obesity is associated with far more serious health consequences than moderate obesity, and creates additional challenges for health care providers.  Between 2000 and 2010, the prevalence of morbid obesity in the U.S. increased by 70%, whereas the prevalence of super obesity increased even faster.  It’s estimated that in 2010, 15.5 million adult Americans, or 6.6% of the population, had an actual BMI >40, and carried the diagnosis of morbid obesity.

MEDICAL PROBLEMS ASSOCIATED WITH OBESITY

Obesity is an independent risk factor for heart disease, hypertension, stroke, hyperlipidemia, osteoarthritis, diabetes mellitus, cancer, and obstructive sleep apnea (OSA).  A neck circumference > 17 inches in men or > 16 inches cm in women is associated with obstructive sleep apnea. As a result of these concomitant conditions, obesity is also associated with early death (Katzmarzyk PT, Janssen I, Ardern CI. Physical inactivity, excess adiposity and premature mortality.  Obes Rev 2003; 4:257-290).

There is a clustering of metabolic and physical abnormalities referred to as the “metabolic syndrome.” To be diagnosed with metabolic syndrome, you must have at least three of the following: abdominal obesity, elevated fasting blood sugar, hypertension, low HDL levels, or hypertriglyceridemia.  In the United States, nearly 50 million people have metabolic syndrome, for an age-adjusted prevalence of almost 24%. Of people with metabolic syndrome, more than 83% meet the criterion of obesity. Patients with metabolic syndrome have a higher risk for cardiovascular disease and are at increased risk for all-cause mortality (Liberopoulos EN. Diagnosis and management of the metabolic syndrome in obesity.  Obes Rev  2005; 6:283-296).

Obstructive sleep apnea (OSA) is a condition characterized by recurrent episodes of upper airway obstruction occurring during sleep. Obesity is the greatest risk factor for OSA, and about 70% of patients (up to 80% of males and 50% of females) with OSA are obese.  OSA is defined as complete blockage of airflow during breathing lasting 10 seconds or longer, despite maintenance of neuromuscular ventilatory effort, and occurring five or more times per hour of sleep (Apnea Hypopnea Index, or AHI, greater than or equal to five), and accompanied by a decrease of at least 4% in arterial oxygen saturation.  This diagnosis can be made only in patients who undergo a sleep study. Obstructive sleep apnea is classified as mild, moderate, or severe, as follows:

  • Mild OSA =A HI of 5 to 15 events per hour
  • Moderate OSA = AHI of 15 to 30 events per hour
  • Severe OSA = AHI of more than 30 events per hour

Treatment is recommended for patients with moderate or severe disease, and initial treatment is the wearing of a continuous positive airway pressure (CPAP) device during sleep. (Patil SP, Schneider H, Schwartz AR, Smith PL: Adult obstructive sleep apnea.  Chest  2007; 132:325-337).

ANESTHETIC CHALLENGES

Every anesthesia task can be more difficult to perform in an obese patient.  Excess adipose tissue (fat) on the upper extremities makes it harder to place an IV catheter.  Excess fat surrounding the mouth, throat, and neck can make it more difficult to place an airway tube.  Excess fat can make it more difficult to place a needle in the proper position for a spinal anesthetic, an epidural anesthetic, or a regional block of a specific peripheral nerve.  On thick, cone-shaped upper arms, it can be difficult for a blood pressure cuff to detect the blood pressure accurately.

During surgery, an anesthesiologist’s job is to maintain the patient’s A-B-C’s of Airway, Breathing, and Circulation, in that order.  All three tasks are more difficult in obese patients.

Airway procedures are often much more difficult to perform in obese patients than in patients with normal BMIs.  Every general anesthetic begins with the anesthesiologist injecting intravenous medications that induce sleep.  Next the anesthesiologist controls the breathing by using a mask over the patient’s face, and then he or she places an airway tube through the patient’s mouth into the windpipe.

The airway anatomy of obese patients, with or without OSA, may show a short, thick neck, large tongue, and significantly increased amounts of soft tissue surrounding the uvula, tonsils, tongue, and lateral aspects of their throats.  This can contribute to the development of airway obstruction and also increase the probability that it will be more difficult to keep the airway open during mask ventilation.  This can also contribute to difficulty placing an anesthesia airway tube into the windpipe at the beginning of general anesthesia.

What about breathing difficulties?  The chief reason that obese patients have difficulty with breathing during anesthesia is that they have abnormally low lung volumes for their size.  When lying flat on their back, a patient’s increased abdominal bulk pushes up on their lungs, and prevents the lungs from inflating fully.  Once the patient is anesthetized, this mechanical situation is worsened, because breathing is impaired by the anesthetic drugs and muscle relaxation allows the abdomen to sink further into the chest.  The essence of the problem is that the abdomen squashes the lungs and makes them less efficient both as a reservoir and as an exchange organ for oxygen.  Because of this, the obese patient is at risk for running out of oxygen and turning blue more quickly than a lean patient.

In one study,  patients undergoing general anesthesia received 100% oxygen by facemask before induction of general anesthesia. After the induction of general anesthesia, the patients were left without ventilation until their oxygen saturation fell from 100% to 90%.  Patients with normal BMIs took 6 minutes for their oxygen level to fall to 90%. Obese patients reached that end point in less than 3 minutes (Jense HG. Effect of obesity on safe duration of apnea in anesthetized humans.  Anesth Analg 1991; 72:89-93).

What about circulation?  Maintaining stable circulatory status can be difficult because obese patients have a higher prevalence of cardiovascular disease, including hypertension, arrhythmias, stroke, heart failure, and coronary artery disease. During anesthesia and surgery, unexpected high or low blood pressure events are more common in obese patients than in those with normal BMIs.  Morbidly obese patients have a higher rate of heart attack postoperatively than patients with normal BMIs (Bamgbade OA. Postoperative complications in obese and nonobese patients. World Journal Surg 2007; Mar;31(3):556-60).

Regional anesthesia, especially epidural and spinal anesthesia, is often a safer technique than general anesthesia in obese patients. However, regional anesthesia can be  technically more difficult because of the physical challenge of the anatomy being obscured by excess fat.

Operative times are often longer in obese patients, owing to technical challenges for the surgeon regarding anatomy distorted or hidden behind excessive fat.  Longer surgery means a longer time under general anesthesia, which is a cause of delayed awakening from anesthesia. At the conclusion of surgery, obese patients wake more slowly than lean patients. Anesthetic drug and gas concentrations drop more slowly post-surgery, because traces of the chemicals linger in the reservoirs of excessive adipose tissue.

Common serious postoperative complications in obese patients include blood clots in the legs (deep venous thrombosis) and wound infections at the surgical incision line.

(Reference for this section:  Miller’s Anesthesia, 7th Edition, 2009, Chapter 64).

DATA ON THE RISKS OF OBESITY AND SURGERY

In one landmark study, researchers analyzed postoperative complications in 6,773 patients treated between 2001 and 2005 at the University of Michigan. Of the patients who had complications, 33% were obese and 15% were morbidly obese. Obese patients had much higher rates of postoperative complications than nonobese patients, as follows:  5 times more heart attacks, 4 times more peripheral nerve injuries, 1.7 times more  wound infections, and 1.5 times more urinary tract infections. The overall death rate was no different for obese and nonobese patients, but the death rate was nearly twice as high among morbidly obese patients as compared with nonobese patients (2.2% vs. 1.2%).  (Bamgbade OA. Postoperative complications in obese and nonobese patients. World Journal Surg 2007; Mar;31(3):556-60).

CONCLUSIONS

Experienced anesthesiologists respect the risks and difficulties presented by obese, morbidly obese, and super obese patients.  The ranks of overweight Americans are growing, and every week we anesthetize thousands of them for surgery.  As an obese American, are you safe in the operating room?  You probably are, because anesthesia professionals are well-educated in the risks of taking care of you. But you must realize that you are at higher risk for a complication than those with a normal BMI.

What can you do about all this? If you are morbidly obese and your surgery is optional, you may consider not having surgery at all.  If you have time before surgery, you can try to lose weight.  Before any surgery, you should consult your primary care physician to make sure that any obesity-related medical problems have been addressed.  You may be placed on medication for hypertension, hyperlipidemia, or diabetes.  You may have undiagnosed OSA, and may benefit from a nightly CPAP treatment for that disorder.

Bariatric surgery (e.g., gastric banding, gastric bypass) is a well-accepted and effective treatment for weight loss in super obese and morbidly obese patients.  Bariatric surgery refers to surgical alteration of the small intestine or stomach with the aim of producing weight loss. More than 175,000 bariatric surgeries were performed in 2006, and more than 200,000 were performed in 2008 (Miller’s Anesthesia, 7th Edition, 2009, Chapter 64). Weight loss after bariatric surgery is often dramatic. On the average, patients lose 60% of their extra weight. For example, a 350-pound person who is 200 pounds overweight could lose about 120 pounds.  All the anesthetic considerations and risks discussed above would still apply to any patient coming to the operating room for weight loss surgery.

Obesity was considered a rarity until the middle of the 20th century.  Now more than 300,000 deaths per year in the United States and more than $100 billion in annual health care spending are attributable to obesity. Obesity most frequently develops when food calorie intake exceeds energy expenditure over a long period of time.

If you’re obese, this doctor recommends you eat less, and exercise more.  Stay lean if you can.  Your anesthesiologist will thank you.

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Introducing …  THE DOCTOR AND MR. DYLAN, Dr. Novak’s debut novel, a medical-legal mystery which blends the science and practice of anesthesiology with unforgettable characters, a page-turning plot, and the legacy of Nobel Prize winner Bob Dylan.

Publication date September 9, 2014 by Pegasus Books.

On October 2, 2014 THE DOCTOR AND MR. DYLAN became the world’s  #1 bestselling anesthesia Kindle book on Amazon.com.

To reach the Amazon webpage, click on the book image below:

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Stanford professor Dr. Nico Antone leaves the wife he hates and the job he loves to return to Hibbing, Minnesota where he spent his childhood. He believes his son’s best chance to get accepted into a prestigious college is to graduate at the top of his class in this remote Midwestern town. His son becomes a small town hero and academic star, while Dr. Antone befriends Bobby Dylan, a deranged anesthetist who renamed and reinvented himself as a younger version of the iconic rock legend who grew up in Hibbing. An operating room death rocks their world, and Dr. Antone’s family and his relationship to Mr. Dylan are forever changed.

Equal parts legal thriller and medical thriller, The Doctor and Mr. Dylan examines the dark side of relationships between a doctor and his wife, a father and his son, and a man and his best friend. Set in a rural Northern Minnesota world reminiscent of the Coen brothers’ Fargo, The Doctor and Mr. Dylan details scenes of family crises, operating room mishaps, and courtroom confrontation, and concludes in a final twist that will leave readers questioning what is of value in the world we live in.

REVIEWS:

5.0 out of 5 stars The Doctor and Mr Dylan, March 3, 2015
By
prabha venugopal (chicago, il USA) – See all my reviews
Verified Purchase(What’s this?)
Gripping from the beginning to the end. Very well written, bringing to the forefront all the human emotions seen in an operating room spill over into real life. I cannot wait for Dr. Novak to wrote another book! As another physician in the same profession, my admiration for his book knows no limits.

Bang-Up Debut Novel, November 16, 2014

By Norm Goldman “Publisher & Editor of Bookpleasures”

This part legal and medical thriller is structured with a mixed bag of situations involving relationships, jealousy, evil, lies, courtroom drama, operating room mishaps as well as moments that engender conflicting and unexpected outcomes. Noteworthy is that as the suspense builds readers will become eager to uncover the truth involving a mishap concerning Nico and a surgical procedure that has unanticipated ramifications.

This is a bang-up debut from a writer who understands timing and is able to deliver hairpin turns, particularly involving the courtroom drama,that you would expect from a book of this genre.

TwinCities.com PIONEER PRESS Entertainment

by Mary Ann Grossman, Entertainment Editor, St. Paul Pioneer Press mgrossman@pioneerpress.com, January 4, 2015

“The Doctor & Mr. Dylan” by Rick Novak (Pegasus Books, $17.50)

Dr. Nico Antone doesn’t hide the fact he hates his wife, but he says he didn’t kill her during an operation. The authorities think otherwise and his trial is the riveting suspense in this novel that is part medical thriller, part legal thriller, part exploration of family relationships.

Nico is an anesthesiologist (as is the author) who leaves his wife, their plush life in California and his job at Stanford to move to his hometown of Hibbing so their son, Johnny, has a better chance of getting into a prestigious college. Johnny hates the idea of moving to a small, cold town, but he’s popular from the first day in school. Nico doesn’t do so well. He’s envied by Bobby, an anesthetist who’s jealous of the better-educated Nico. But it’s hard to take Bobby seriously, since he thinks he’s the young Bob Dylan and lives in the house where Bobby Zimmerman grew up. To complicate matters, Nico is attracted to the mother of the young woman his son is dating. When the two teens get in trouble, Nico’s furious, rich wife comes to Minnesota and needs an emergency operation that puts her on Nico’s operating table.

Novak grew up in Hibbing, where he worked in the iron ore mines and played on the U.S. Junior Men’s Curling championship teams of 1974 and ’75. After graduating from Carleton College, he earned a medical degree at the University of Chicago and spent 30-plus years at Stanford Hospital, where he was an associate professor of anesthesia and Deputy Chief of the Anesthesia Department. His courtroom scenes are based on his experiences as an expert witness.

The Physician’s Late-Night Reading List

Two Pritzker alums pen captivating tales

By Brooke E. O’Neill, University of Chicago Pritzker School of Medicine, editir, Medicine on the Midway Magazine

For most physicians, writing — patient notes, case histories, perhaps journal articles — is part of the job. But for anesthesiologist-novelist Rick Novak, MD’80, and neurosurgeon-memoirist Moris Senegor, MD’82, it’s a second career that consumes early morning hours long before they step into the OR.

Fans of John Grisham will find a kindred spirit in Novak, whose fast-paced medical thriller, The Doctor & Mr. Dylan (Pegasus Books, 2014), transports readers to rural Northern Minnesota, where an accomplished physician and a deranged anesthetist who thinks he’s rock legend Bob Dylan see their worlds collide in the most unexpected ways.

Delivering real-life twists and turns — and a love letter to the Bay Area — is Senegor’s Dogmeat: A Memoir of Love and Neurosurgery in San Francisco (Xlibris, 2014), a coming-of-age tale chronicling the author’s away rotation with renowned neurosurgeon Charles Wilson, MD, at the University of California, San Francisco. Brutally honest, it spares no details of a time Senegor, who also served as a resident under the University of Chicago’s famed neurosurgery chair Sean Mullan, MD, describes as “one of the biggest failures of my life.”

One a vividly imagined nail-biter, the other an intimate peek into the surgical suite, both books deliver an ample dose of intensity and drama.

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The Doctor and Mr. Dylan (Pegasus Books, 2014) by Rick Novak, MD’80

“I thought it was a novel way of killing someone,” said Rick Novak, deputy chief of anesthesiology at Stanford University, describing the imagined hospital death that was the genesis of his dark thriller The Doctor & Mr. Dylan. A huge Bob Dylan fan — the rock icon was born in Novak’s hometown of Hibbing, Minnesota, where the story takes place — he then dreamed up a possible culprit: a psychotic anesthetist who thinks he’s Dylan.

From there, the words flowed. “I would write whenever I was with my laptop and had a free moment: in mornings, in evenings, in gaps between cases,” said Novak, who also blogs about anesthesia topics. “I don’t sleep much.”

After finishing the manuscript — one year to write, another to edit — came the challenge of finding a publisher. “In anesthesia, I’m an expert,” Novak said. “In the literary world, I’m an unknown.” After 207 responses of “no, thanks” or no answer at all, he landed an agent. Two months later, she informed him that Pegasus Books had bought his debut novel.

“I started crying,” Novak admits. “I have a third grader and at the time the big word the class was learning was ‘perseverance.’ That was it exactly.”

Dr. Joseph Andresen, Editor, Santa Clara County Medical Association Medical Bulletin, from the January/February 2015 issue:

BOOK REVIEW “THE DOCTOR AND MR. DYLAN”

This past month, Dr. Rick Novak handed me a hardbound copy of his debut novel The Doctor and Mr. Dylan. Rick and I go way back. It was my first week of residency at Stanford when we first met. A newcomer to the operating room, all the smells and sounds were foreign to me despite my previous three years in the hospital as an internal medicine resident. Rick, a soft spoken Minnesotan at heart, in his second year of residency, took me under his wing and guided me through those first few bewildering months, sharing his experience and wisdom freely.

Fast-forward 30 years later. Dr. Rick Novak, a novel and mystery author? This was new to me as I sat down and opened the first page of The Doctor and Mr. Dylan. I have to admit that I didn’t know what to expect. Few books highlight a physician/anesthesiologist as a protagonist, and few books feature a SCCMA member as a physician/author. However, a medical-mystery theme novel wasn’t at the top of my must read list. With my 50-hour workweek, living and breathing medicine, imagining more emotional stress and drama was the furthest thing from my mind. However, three days later, as I turned the last page, and read the last few words. “life is a series of choices. I stuck my forefinger into the crook of the steering wheel, spun it hard to the left and …” This completed my 72-hour journey of and free moments I had, completely immersed in this story of life’s disappointments, human imperfections, and simple joys.

Rick, I can’t wait for your next book. Bravo!

Hibbingite writes twisted medical tale

HIBBING — Readers who are looking for a whodunit that will keep them up all night are in for a treat.

Hibbing native Rick Novak recently released his first book “The Doctor and Mr. Dylan,” a fiction set in Hibbing that merges anesthesia complications, a tumultuous marriage and the legend of Bob Dylan.

“The dialogue is sometimes funny, and there are lots of plot twists,” he said.

Novak said the book will not only entertain readers, but teach them about anesthesiology, Dylanology, the stressful race for elite college admission, and life on the Iron Range.

“The book is very conversational and streamlined,” he said. “I try to write as one would tell a story out loud.”

Novak said “The Doctor and Mr. Dylan” took him three years to perfect. He is currently working on his second book.

5.0 out of 5 stars I Sense We Have Another F.Scott Fitzgerald Emerging on the Literary Scene, December 1, 2014
By
Deann Brady (Sunnyvale, CA USA) – See all my reviews
(REAL NAME)
I found Rick Novak’s first novel, “The Doctor and Mr. Dylan,” a most exciting combination of biting sarcasm, mystery and daily activity spun with fresh new phrases that made me turn my ear back to listen to the literary cadence of his words again and again even though, on the other hand, I was anxious to turn the pages to see what would happen next. His brilliant handling of scenes is reminiscent of The Great Gatsby by F. Scott Fitzgerald. A compelling read!Deany Brady, author of “An Appalachian Childhood”

By

allan mishra

This review is from: The Doctor and Mr. Dylan (Kindle Edition)

Just finished Dr. Novak’s delightful novel. I sincerely enjoyed his honest take about the pressures and values that exist within California’s Silicon Valley. He also brought the North Country of Minnesota to life with memorable characters and a twisting, addictive plot. Buried beneath the fun and funny story is a deeper message about how to best care for your kids, your relationships and yourself. Very well written and highly recommended.

Learn more about Rick Novak’s fiction writing at rick novak.com by clicking on the picture below:

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