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Morbid Obesity and Gastric
Bypass
Fun Facts
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61% of adults in US have
BMI >25 in ’99
13% of children 6-11
14% of adolescents aged
12-19
How many deaths in the
US are associated with
obesity?
Economic Cost?
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National Institute of Health. Call to
Action Report
Deaths and Cost
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300,000 deaths per year
BMI >30 have a 50%-100% increased risk
of premature death.
117 BILLION dollars in 2000
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National Institute of Health. Call to Action Report
More Fun Facts
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More non-Hispanic white women(23%)
are obese compared to non-Hispanic white
men(21%)
Most affected-women are of low
socioeconomic.
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National Institute of Health. Call to Action Report
Taco Bell?
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Mexican american
boys tend to have
higher prevalence of
overweight.
National Institute of Health. Call to
Action Report 1998
Heart Disease
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Hypertension twice as
common
Increased risk: MI,
CHF, Sudden Death,
Arrythmias.
Diabetes
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A gain of 11-18 lbs
increases the risk of
developing Type 2 to
twice that of normal
individuals
Over 80% of people
with DM type 2 are
overweight or obese
Respiratory
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Sleep Apnea
Obesity Hypoventilation Syndrome
Asthma
Decreased FRC
Increased risk of aspiration from GERD
Difficult airways (ventilate and intubate)
Other
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Arthritis
Reproductive complications
Gallbladder disease.
Depression, Social Discrimination
What is BMI?
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Body Mass Index
BMI=weight (kg) /
height (m2)
BMI=pounds/inches 2
x 703
Why BMI?
Classification
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Healthy Weight 18.524.9
Overweight 25.0-29.9
Obesity
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Class I 30.0-34.9
Class II 35-39.9
Class III >40
Limitations to BMI….really?
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Overestimate body fat
in persons who are
very muscular i.e.
body builders
Underestimate body
fat in persons who
have lost muscle
mass i.e. elderly
Surgery Aspect
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Indications
Types
Results
Complications
Indications
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Age 18-60
BMI > 40
BMI > 35 with
medical problems
Exhausted other
venues of weight loss
Types of Surgery
How do they work?
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Restrictive
Malabsorption
Behavioral modification
Results
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Weight Loss- 66% at 1 to
2 years after surgery
60% at 5 years
50% at 10 years
African-american lose
significantly less
weight…why?
Improvement in
comorbities
Complications
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Akin to any surgery i.e. infection, DVT,
wound deshicense, anastomotic leaks, etc.
Death 1%-2% after surgery, but higher
with other comorbities.
Irritable bowel syndrome ….can lead to
rectal problems
Anesthesia
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Pre-Op
Intra-Op
Post-Op
Pre-Op/ History
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History and Physical
ROS
Airway
Heart
Lungs
Eyes… eyes?… yes
eyes
Previous anesthesia
Airway
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Mallampati, mouth opening, tongue size,
thyromental distance, sternomental distance,
neck circumference
Predictibility of difficult intubation: neither
obesity or BMI predicted problems with tracheal
intubation… BUT HIGH MALLAMPATI SCORE >3
and LARGE NECK CIRCUMFERENCE MAY
INCREASE THE POTENTIAL FOR DIFFICULT
LARYNGOSCOPY AND INTUBATION
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Anesthesia and Analgesia, Mar 2002. 732-736
Cardiovascular
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HTN: multiple
medications difficult
to control
Cardiomyopathy,
CHF, Ischemia, CVA,
Pulmonary HT, DVT,
PE,
Hypercholesterolemia,
Hypertriglyceridimia
Obesity Cardiomyopathy
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Patients with severe and long standing
obesity
LVH, left ventricle dilation and LV diastolic
dysfunction.
Left Ventricle Failure and Right Ventricle
Failure = Obesity Cardiomyopathy
Causes of death are CHF and sudden
cardiac death
Lungs/ OSA
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OSA- hypersomnolence, loud snoring,
apnea and hypopnea during sleep
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Physiologic changes:
Arterial hypoxemia
 Polycythemia
 Arterial Hypercarbia
 HTN
 Pulmonary hypertension
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Lungs/ OSA
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Risk Factors:
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Male
Middle Age
Obesity
Alcohol
Drug Induced Sleep
Lungs/OHS
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Obesity Hypoventilation Syndrome is
defined as:
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PaO2 < 70
PaCO2 > 45
BMI > 30 kg/m2
No other respiratory disease of explaining the
gas anomaly
Lungs/OHS
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Why is there
hypoventilation?
1. High cost of work
of respiration
2. Dysfunction of the
respiratory center
3. Repeated episodes
of nocturnal
obstructive apnea
Lungs/OHS
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Physiologic Changes:
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Hypersomnolence (also
OSA)
Arterial Hypoxemia (also
OSA)
Polycythemia (also OSA)
Hypercarbia (also OSA)
Respiratory acidosis
Pulmonary hypertension
(also OSA)
RV Failure (also OSA)
Lungs/OHS
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Some say that OHS progress into OSA
Some say that they are different entities.
Who is right?
OHS are usually:
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Older, more obese, more deranged daytime
ABG values, more restricted lung volume,
more severe desaturation during sleep.
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Chest, 2001:120:336-339
Lungs/ OSA vrs OHS
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Chicken or the egg?
A spectrum of the
same disease?
Eyes
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Hypoxia and
hypercarbia as a sign
of angiogenesis
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Case Report , Elia J.
Duh, AMA-Assn.org
Intra Operative
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GA vrs TIVA
GA supplemented with regional
Fast onset and fast offset medication
Good muscle paralysis
Calculate drug doses according to IBW
Best choice of maintenance is….
NOT KNOWN
Post Op
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Extubation
Post Op Pain
OSA and OHS
Cardiac
Post Op/Extubation
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Fully awake
Recover in head up
positioning
Monitoring very
important if OSA or
OHS
Post Op/Extubation
Maximun decrease in PaO2 is 2-3 days post
op.
Mechanical weaning can be difficult b/c:
1. Increased work of breathing
2. Decresed lung volumes
3. V/Q mismatch
Pain Control and OSA
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Pt with OSA have a exquist sensibility to
narcotics, even when used in regional
techniques.
Narcotics can have depressive effects up
to 2-3 days post op
Post Op/ Others
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Others:
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DVT early ambulation/ heparin
Wound infection is twice as common
Guillain-Barre
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Case Report: Chang; Obes Surg 2002 Aug; 12(4) 592-97