Definitions
What is the body fat fraction in males and females that classifies them as obese according to the WHO?
male: >25%
female: >35%
50%
increased gastric volume, increased acidity, decreased gastric emptying, increased incidence of hiatal hernia and GERD
Is MAC better than GA?
Which method of anesthesia is best?
MAC has higher rate of respiratory complication and airway management complications than GA, awake with local is best.
I: 30-34.9
II: 35-39.9
III: >40
What happens to O2 consumption, Co2 production and what lung volumes/capacities decrease?
Increased O2 consumption and Co2 production.
FRC, VC and TLC decrease.
endocrine: DMII and hypothyroidism
renal: kidney injury d/t glomerular hyperfiltration (Inc total blood volume)
What axes are aligned with ramping the patient and at what level should the auditory meatus be?
oral, pharyngeal, laryngeal.
auditory meatus at the level of the sternum
How should the obese patient be emerged?
Fully awake, fully reversed, sitting up in high fowlers position
DMII, HTN, CAD, Cancer, Infertility, Osteoarthritis, gallbladder disease, respiratory complications.
What happens to total blood volume and
what is the estimated blood volume for the obese population?
Total blood volume increases d/t increase body mass but volume per kilo is decreased to 45-55ml/kg
What is the criteria for metabolic syndrome?
3 or more
-increased waist circumference
( m: >40, f: >35)
-increased triglycerides (>150mg/dl)
-reduced HDL ( <40m, <50f)
-HTN (sys> 130 and/or dias >85)
- Increase fasting glucose (>100)
or use of meds for hyperglycemia.
What are concerns with increasing BMI, lithotomy and Trendelenburg positioning?
What is the optimal position?
Lithotomy: develop neuropathy, compartment syndrome
Trendelenburg: mechanical disadvantage to ventilation
optimal: lateral decubitus
What bariatric procedures are categorized as malabsorptive and what vitamin is affected?
vitamin B12
What is the formula for BMI and IBW?
BMI: Kg/M(squared)
IBW:
female: cm - 105 | 45.5kg + 2.3kg x inch over 5ft
male: cm - 100 | 50kg + 2.3kg x inch over 5ft
Why is there hypercoagulability in the obese population?
What is the classification of mild, moderate and severe disease using the apnea/hypopnea index?
mild: 5-15/hr
moderate: 15-30/hr
severe: >30hr
What happens to Vd for lipid and water soluble drugs, which is more affected?
How does this affect loading dose and maintenance doses?
Vd increases for both, lipid soluble drugs are more affected
Increased loading dose and decreased maintenance doses.
What bariatric surgery is considered the "gold standard"?
Roux-en-y
what is the difference between gynecoid and android fat distribution and which has a higher mortality?
Android - high intraperitoneal fat, increased neck circumference, minimal physiologic reserve
Gynecoid - fat is mostly extraperitoneal, more distribution to arms, legs, hips.
Android has higher risk of mortality.
How does increased total blood volume contribute to biventricular failure?
increased LV workload-> LV hypertrophy-> LV failure
increased pulm HTN-> increased RV workload-> RV failure
increased systemic and pulmonary HTN
R and L ventricular hypertrophy
cardiac arrhythmias
What medications use TBW for dosing?
suggamadex, neostigmine, succinylcholine, propofol drip and precedex drip.
What bariatric surgeries are associated with increased risk of aspiration?
Gastric banding, intragastric balloon