Obesity

Question 1

Define obese.

Answer 1

20% above their IBW

BMI > 28

Question 2

Define morbid obesity.

Answer 2

> 45 kg above their IBW
2x IBW
BMI > 35

Question 3

BMI Formula.

Answer 3

kg/m2
o 1 inch = 0.0254 meters
o 1 inch = 2.54 cm
o 1 foot = 12 inches

Question 4

Respiratory changes resemble restrictive or obstructive disease?

Answer 4

Restrictive 
Chest wall compliance decreased 
Diaphragm is elevated - diaphragm breather
WOB increased
Decreased - ERV, IC, VC, TLC, FRC

Question 5

Does the basal metabolic rate change in obesity?

Answer 5

NO - unchanged b/c it is related to body surface area

Oxygen demand increases

Question 6

What happens to PaO2 and PaCO2 in the obese patient?

Answer 6

Decreased PaO2

Normal PaCO2

Question 7

IBW Formula.

Answer 7

Men: Height in centimeters minus 100
Women: Height in centimeters minus 105

Question 8

BMI
< 18.5
18.5-24.9
25-29.9
30-34.9
35-39.9
> 40

Answer 8

< 18.5 - underweight 
18.5-24.9 - normal 
25-29.9 - overweight 
30-34.9 - Class I 
35-39.9 - Class II 
> 40 - Class III - morbid obesity

Question 9

What is the most sensitive indicator of the effect of obesity on pulmonary function?

Answer 9

ERV

Question 10

Cardiovascular Changes

INCREASED

Answer 10

CO

BV (50 mL/kg) - eccentric hypertrophy

Question 11

Obesity increases the incidence of…

Answer 11

CHF
Pulmonary and systemic hyperperfusion 
Hypercholesterolemia
Hypertriglyceridemia
DM
IHD
Cardiomegaly
Pulmonary HTN

Question 12

Explain the obese patient’s response to exercise.

Answer 12

Faster rise in CO in response to exercise than non-obese patients, fueled primarily by an increase in HR as the SV changes little with exertion

Require a higher CO and BV to perfuse the extra adipose tissue - this is maintained by an increase in SV, not HR

Question 13

Give water soluble drugs according to…

Answer 13

IBW 
o	Muscle relaxants 
o	Remi
o	Digoxin
o	Cimetidine
o	Anticoagulants
o	Procainamide

Question 14

Give lipid soluble drugs according to…

Answer 14

Total body weight 
o	Sux
o	Maintenance dose of propofol (induction dose based on LBW)
o	Loading dose of Fentanyl 
o	Neostigmine 
o	Sugammadex 
o	Precedex
o	Benzos

Question 15

What is the most accurate indicatory for a difficult airway in an obese individual?

Answer 15

Neck circumference

BMI does NOT seem to have much influence of the difficult of laryngoscopy

Question 16

What is the most common mononeuropathy after bariatric surgery?

Answer 16

Carpal tunnel syndrome

Question 17

What is the most common and dangerous post-op problem in the obese population?

Answer 17

Respiratory failure

Question 18

What is Pickwickian syndrome?

Answer 18

Obesity-hypoventilation syndrome

Occurs in 8% of the obese population

Question 19

What hematological alteration is seen in Pickwickian syndrome?

Answer 19

Cyanosis-induced polycythemia due to chronic hypoxia and hypercapnia

Question 20

What is the significance of Phen-Fen?

Answer 20

Diet supplement associated with heart valve disease

*Could also be on SSRIs - hypotension, tachycardia, anxiety, catecholamine depletion - neo is effective tx

Question 21

Over what period of time is tumescent liposuction fluid (Lidocaine 0.05-0.1% + 1:1,000,000) absorbed?

Answer 21

Absorbed over 48 hours
*Lidocaine plasma concentration peaks anywhere from 10-14 hours post-op

(1 mL of wetting solution for every 1 mL of fat to be removed…with volumes approaching 5000 mL concern for volume overload)

Question 22

Difficult intubations are expected in up to ___% of patients with OSA.

Answer 22

25%

*Candidates for awake intubation

Question 23

What accounts for up to 25% of deaths during liposuction?

Answer 23

PE