What are the metabolic/endocrine co-morbidities we can see w/obesity?
Type 2 Diabetes
What Heamatologic co-morbidities can we see w/obesity?
What GU/Reproductive co-morbidities can we see w/obesity?
End-stage Renal Disease
Preeclampsia and Eclampsia
What are the neurologic co-morbidities we can see w/obesity?
Carpal Tunnel Syndrome
What is a pseudotumor cerebri?
intracranial pressure increases for no obvious reason.
Symptoms mimic those of a brain tumor, but no tumor is present
The increased intracranial pressure associated with pseudotumor cerebri can cause swelling of the optic nerve and result in vision loss.
What are the Musculoskeletal co-morbidities seen w/obesity?
Acanthosis Nigricans (Dark pigmentation in folds of skin)
What are the psychologic things we can see w/obesity?
What changes might we see with the respiratory system? (FRC & ERV)
Increased demand for ventilation and breathing workload.
Respiratory muscle inefficiency.
Decreased FRC and ERV.
The aforementioned often result in ventilation-perfusion mismatch, especially in the supine position.
What changes in compliance do we see with the respiratory system in obesity?
Excess thoracic and abdominal fat decrease chest wall and lung compliance.
Decreased total respiratory compliance in supine position due to: Increased elastic resistance & Decreased compliance of chest wall.
Decreased pulmonary compliance leads to decreased FRC, VC and TLC.
What is the primary cause of decreased FRC in obesity?
Reduced ERV is primary cause of decreased FRC
What are the MOST COMMON abnormalities in pulmonary function?
Decreased ERV and FRC are most common abnormalities in pulmonary function
What can the decrease in FRC lead to in the obese patient?
Reduced FRC may lead to small airway closure, VQ mismatch, right-to-left shunting and ultimately, arterial hypoxemia
How much can anesthesia reduce FRC in the obese patient, compared to the non-obese?
Anesthesia reduces FRC up to 50% in obese patients compared with 20% of non-obese
What is the most sensitive indicator of the effect of obesity on pulmonary function?
What does increased workload on supportive tissues as well as metabolic activities do?
increase oxygen consumption and CO2 production
Define obstructive sleep apnea
complete cessation of airflow during breathing lasting 10 seconds or longer despite maintenance of ventilatory effort, occurring 5 or more times per hour of sleep, accompanied by a decrease of at least 4% in SaO2.
Define obstructive hypoventilation syndrome
partial reduction of airflow of greater than 50% lasting at least 10 seconds, occurring 15 or more times per hour of sleep, accompanied by a decrease of at least 4% in SaO2
How are the obstructive respiratory disorders diagnosed?
Diagnosed by polysomnography with monitoring of: EEG, ECG, EOG, ETCO2, SaO2, blood pressure, nasal or oral airflow, esophageal pressure and electromyelogram.
Obesity is the GREATEST risk factor for what respiratory problem?
Why does obesity cause OSAHS?
Increased amount of oral and pharyngeal adipose tissue (uvula, tonsils, tonsillar pillars, tongue, aryepiglottic folds and lateral pharyngeal walls).
__% of patients with OSAHS are obese.Up to __% of males and __% of females.
70; 80; 50
OSAHS plays an important role in systemic inflammation, how?
Cyclic episodes of hypoxia and reoxygenation activate the SNS → elevated levels of proinflammatory cytokines and oxidative stress of vascular endothelium → increases systemic inflammation
What are the consequences (associated co-morbidities) of OSA?
Pulmonary hypertension (less common)
Secondary polycythemia (due to hypoxemia)
Left ventricular hypertrophy
Increased risk for cerebral vascular disease
What may Obesity Hypoventilation Syndrome (a.k.a. Pickwickian Syndrome) result from?
May result from long-term OSA.
What did recent studies suggest may play a role in Obesity Hypoventilation syndrome (Pickwickian Syndrome)?
Recent studies suggest leptin resistance may play a role.
Obesity Hypoventilation Syndrome (Pickwickian) is Alveolar hypoventilation independent of intrinsic lung disease. What populations is this common in?
Most common in older patients and the super obese.
What are the consequences (associated co-morbidities) of Obesity Hypoventilation Syndrome (Pickwickian)
Hypoxemia and hypercarbia
RV enlargement → failure
Cardiac output increases as weight increases (up to ___-__ ml/kg of excess body fat) → increased total blood volume.
20-30 ml/kg of excess body fat
Mild to moderate hypertension is seen in majority of obese patients, what does this cause?
Causes eccentric ventricular hypertrophy.
Left ventricular wall thickening and increased heart volume may lead to cardiac failure
Even if the obese patient is normotensive, what might increases might we see cardiovascularly?
Increased pre-load, after-load, PA pressures and elevated LV and RV stroke work are present in normotensive patients.
Increased stroke volume and ventricular dilation lead to increased left ventricular wall stress. What does this result in?
hypertrophy, decreased compliance, and diastolic dysfunction with elevated left ventricular and diastolic pressures and pulmonary edema.
If rate of left ventricle dilation exceeds rate of thickening, cardiomyopathy, and potentially biventricular failure occur.
Why do we see an increase in total blood volume in the obesity patient?
Due to perfusion of excess fat.
Result of polycythemia of chronic hypoxemia
In obesity cardiomyopathy which kind of HF is more common?
Diastolic heart failure is most common, but some exhibit systolic and diastolic dysfunction
Risk of heart failure rises steeply after___ years of severe obesity
Signs and symptoms of obesity cardiomyopathy most commonly occur in patients with a BMI > __ or body size > ___% IBW
What is the good news about the cardiomyopathy seen in obese patients?
Many of the manifestations and cardiac structure and function are reversible with substantial weight loss
What happens to the gastric volume and acidity in the obese patient?
Increased gastric volume and acidity
Many have volume >25 ml and pH <2.5
Why does the obese patient have delayed gastric emptying?
Delayed gastric emptying due to increased abdominal mass causing antral distention, gastrin release, and decreased pH.
A greater than 3.5 kg/m2 increase in BMI is associated with a ___-fold increase in risk for developing reflux symptoms
What are the features of Non-alcoholic Steatohepatitis/Non-alcoholic Fatty Liver Disease?
Subclinical hypothyroidism in approximately __% of obese patients
What are the effects of the subclinical hypothyroidism in the obese patient?
Elevated levels of TSH.May be associated with hypoglycemia, hyponatremia, and impaired hepatic drug metabolism
Metabolic syndrome affects nearly ___ million in U.S.
Who is affected more by metabolic syndrome, men or women?
Men > women
What does metabolic syndrome place the patient at increased risk for?
Type 2 diabetes→atherosclerotic disease
What are the features of Metabolic Syndrome?
Polycystic ovary syndrome
Nonalcoholic fatty liver disease
Decreased high-density lipoprotein (HDL)
Insulin resistance with or without glucose intolerance
Clinical Criteria for Metabolic Syndrome (require at least three)
Abdominal Obesity: Waist circumference >102 cm in men and >80 cm in women
Elevated Fasting Glucose: >110mg/dl
Low HDL levels: <40 mg/dl in men and <50 mg/dl in women
Why is the obese patient more prone to blood clots?
Increased levels of fibrinogen, factors VII and VIII, von Willebrand factor, and plasminogen activator inhibitor-1
What two things are increased that increase and activate factor VII
Increased triglycerides → increased factor VII.
Lipemia → activates factor VII
Hyperinsulinemia induces endothelial dysfunction, what does this do to coagulation?
increases factor VIII levels and Von Willebrand factor → fibrin formation
In 1950’s Open intestinal bypass started. What was this?
Weight loss purely by malabsorption of food.
Bypassed all but 12-14 inches of small bowel (approximately 29 feet), the stomach left unchanged
1970’s, Open intestinal bypass us abandoned. Why?
Serious nutritional problems.
In the 1970s, the Vertical Banded Gastroplasty (VBG) introduced by Dr Ed Mason in Iowa. What is this?
Weight loss by restricting the intake of food in the stomach, with small bowel left unchanged.
Stomach was reduced from approximately two quarts to one ounce using a surgical stapler.
The gastric outlet reduced to ½ inch (one cc) with a plastic band to keep it from stretching.
The small pouch and rigid outlet resulted in vomiting and acid reflux.
In 1970s, the vertical banded gastroplasty had what results?
Average weight loss approximately half the patients’ excess weight.
Long term, 50% of patients had revisions, conversions or reversals due to complications or weight loss failure
In the early 90’s: Roux en Y Gastric Bypass (RNY) developed by Dr.’s Wittgrove and Clark. What is this?
Combined gastric restriction to limit food intake with some limited malabsorption of food in the small bowel.
Stomach reduced to a one-ounce pouch with a narrow opening, without utilizing band for permanent restriction of the outlet, and the distal stomach and proximal small bowel were bypassed for approximately 5 feet.
Roux en Y Gastric Bypass (RNY) developed in the 1990s had what results?
Sustained and greater weight loss compared to the VBG.
Ultimately became the most popular weight loss surgery in the U.S.
Averaged 75% excess weight loss.
90% success rate after 5 years in most studies
In 1992 the National Institutes of Health (NIH) held a consensus conference of medical experts to evaluate bariatric surgery and its role in treating morbid obesity. NIH found there were two procedures which they felt were safe and effective for treating morbid obesity, what were they??
vertical banded gastroplasty and the Roux gastric bypass
NIH set the standard to qualify for surgery, what are they?
100 pounds over IBW
or BMI of 40 without health issues
or BMI between 35- 39 with associated medical problems.
The first laparoscopic gastric bypass performed and the laparoscopic approach was quickly adopted for vertical banded gastroplasty. When was this?
Laparoscopic adjustable gastric band (initially introduced in Europe to replace the VBG) was approved for clinical trial in the U.S. when was this?
1990’s: Duodenal switch introduced by a small number of surgeons (< 5%) in the U.S, what is this?
Combined gastric and intestinal bypass procedures with both a reduction in stomach volume and a radical bypass of the small bowel, bypassing all but 3-5 feet of the 30 foot intestine.
What types of patients is the duodenal switch performed in?
Used more often in super obese patients with a BMI greater than 60, often weighing 600-800 pounds.
Why was the duodenal switch not accepted too well?
Never widely accepted by patients or surgeons due to its significant risk of malnutrition and frequent watery diarrhea
What came out of the duodenal switch by accident?
Gastric sleeve procedure
A group of surgeons began breaking the Duodenal Switch procedure into two separate operations performed 6 months apart in order to reduce operating time and associated risks
The stomach size was first reduced by performing the gastric sleeve procedure resulting in about a 100-pound weight loss in 6 months.
The second operation would bypass the small bowel and reattach the gastric sleeve to the distal small bowel to form the completed duodenal switch
Once it was found by accident, the gastric sleeve was used in patients with a BMI of what?
Surgeons began using the gastric sleeve in patients with a BMI of 40-50
Currently approximately __% of weight loss surgeries in the U.S. are gastric bypass and __% are adjustable bands or sleeve gastrectomies.
Describe the RNY surgery today
Routes food past most of the stomach and first part of the small intestine.
This both restricts food intake and decreases absorption of nutrients.
Using a surgical stapler, a small stomach pouch is created.
Small bowel is divided approximately two feet from the stomach.
Gastrojejunostomy is created, followed by a jejunojejunostomy
Describe the Sleeve Gastrectomy today
Restrictive procedure removing approximately 2/3 of the stomach, providing faster satiety and decreased appetite.
Small sleeve created with a surgical stapler along inside curve of the stomach, from the pylorus to the esophagus, and the remainder of the stomach removed.
The pyloric valve remains, allowing for the feeling of fullness.
Describe the gastric band surgery today
A small pouch is created by placing an adjustable band at the top of the stomach to reduce it’s size.
A small epidermal port allows for adjustment of the band to make the pouch smaller or larger.
What is the Biliopancreatic Diversion?
Restrictive: Approximately 70% of the stomach is removed which produces both restriction of food intake and reduction of acid output.
Malabsorption: achieved by bypassing both the duodenum and jejunum of the small intestine and taking food from the stomach directly to the distal part of the digestive tract.
This bypass reduces the length of functioning small intestine (where most nutritional uptake occurs) so that a significant amount of fat and other macronutrients pass through, undigested.
Greater weight loss and higher complication rate than other procedures.
What are the PROS of the RNY surgery?
Sustained and greater weight loss with dietary compliance.
Potential reversal of diabetes,hypertension, dyslipidemias, nonalcoholic steatohepatitis, sleep apnea and obesity-hypoventilation syndrome, cardiac dysfunction, reflux esophagitis, pseudotumor cerebri, arthritis, infertility, stress incontinence, and venous stasis ulcers.
Decreases secretion of ghrelin.
What are the CONS of the RNY surgery?
Malabsorption à nutritional deficiencies and anemia (secondary to malabsorption of vitamin B12).
Decreased absorption of calcium may lead to osteoporosis and metabolic bone disease.
What are the PROS of the sleeve gastrectomy?
Decreases size of stomach and decreases secretion of ghrelin.
No malabsorption à no vitamin or mineral deficiencies.
No anastomoses or rerouting of intestinal tract.
What are the CONS of the sleeve gastrectomy?
Potentially slower weight loss than RNY.
Potential for gastric leaks at staple sites.
Limited long-term clinical data.
What are the PROS of the gastric band?
No resection of stomach.
No vitamin or mineral deficiency.
No anastomoses or rerouting of intestinal tract.
No protein-calorie malabsortption.
What are the CONS of the gastric band?
Less weight loss.
Routine follow-up adjustments required. For adjustments in the band
Mechanical failure due to port or tubing leakage.
Slippage or band erosion.
What are the Pros and Cons of Biliopancreatic Diversion?
PRO: Greatest weight loss of all bariatric procedures.
Cons: More technically difficult to perform
laparoscopically. Higher rate of complications.
There are many benefits of gastric bypass surgery, a study published in (JAMA) in 2004 showed improvements in the following conditions:
Remission of type 2 diabetes in 76.8% and significantly improved in 86% of patients.
Elimination of hypertension in 61.7% and significantly improved in 78.5% of patients
Sleep apnea was eliminated in 85.7% of patients.
Joint disease, asthma and infertility dramatically improved or resolved.
Patients lost between 62 and 75 percent of excess weight
What are the early complications of gastric bypass surgery?
What are the late complications of gastric bypass surgery?
Cholelithiasis and/or cholecystitis
What are the contraindications to bariatric surgery?
Persistent alcohol and drug dependence.
Uncontrolled severe psychiatric illness.
Cardiopulmonary disease that would make surgical risk prohibitive
Severe obesity is not associated with increased mortality but what is it associated with?
with increased length of hospital stay and greater risk of renal failure and prolonged assisted ventilation.
What two things are associated with higher rate of surgical complications (mentioned in Christine's lecture)?
BMI > 50kg/m2 and cigarette smoking associated with higher rate of surgical complications
Age greater than ___ associated with increased mortality
12-lead ECG in all patients with at least 1 risk factor for cardiac disease, poor exercise tolerance, or both. What things might we see on the EKG?
Signs of right ventricular hypertrophy (including right-axis deviation and RBBB) suggest pulmonary hypertension
Physical exam and ECG often underestimate presence and degree of cardiac pathology and dysfunction in obese patients, why is this
Adipose tissue may obscure JVD.
Heart sounds are often distant
Why might CV disease be masked in the obese patient?
Obese patients are often inactive, so may have cardiovascular disease and be asymptomatic
Young, asymptomatic patients often have some level of left ventricular dysfunction.
What kinds of things are we assessing for the presence of in our cardiac pre-op eval?