obesity Flashcards
obesity stats
2nd leading cause of preventable death
68% of pop considered overweight/obese
multifactoral chronic disease
Ideal Body Weight
male: 105lbs +6lbs for ever inch over 5ft
female: 100lbs +5lbs for evert inch over 5ft.
* *helpful in calculating drug dose to avoid toxicity or hemodynamic instability
Body Mass Index
-accepted measure of of body build that normalize for adiposity and height
kg/m2
overweight
BMI 25-29
weight is 20% more than ideal body weight
obesity
BMI> 30
have deviations in anatomic, physiologic, biochemical
-associated with morbidity of stroke, ischemia heart disease, DM, certain CA
morbidly obese
BMI>40
super-obese
BMI>50
class 123
1: BMI 30-34
2 35-39
3 >40
increased incidence of DM and heart vascular disease leads to
difficult intubation decreased PaO2 increased gastric volume decreased gastric pH increased post op wound infection increased rick of pulm embolism sudden death poor 30 day outcome
obesity problems
obstuctive sleep apnea (restrictive lung disease
HTN
Ischemia heart disease
CHF
delayed gastric emptying—aspiration risk
DM
hepatobiliary disease
Thrombembolic disease- needs SCD, sub heparin
musculoskeletal disease
Post Op DVT risk factors
venouse stasis
BMI >60?
trunkalobesity
OSA
resp changes obesity
decreased FRC: less safe apnea time
decreased ERV
increase MV
TV may fall into range of closing capacity
increase O2 consumption/CO2 production
decreased chest wall compliance
increased pull resistance: restrictive lung pattern
Pulm function test may remain normal: until obesity worsens and see lung disease and pulm HTN
positing changes obesity
supine: difficulty preO2ing, sniffing position, can see rapid desat
trendelenberg: can lead to V/Q mismatch, hypoxemia, increased R to L shunt
obesity and airway
abundant soft tissue inure airway
obstruction of airway
can impair mandible and cervical mobility creates difficulty maintaining a mask airway
difficult laryngoscopy and intubation
**consider fiberoptic
difficult airway: 5% risk neck circum of 40
35% risk neck circum of 60
Ramp up
premade wedge, or blankets
pt at 25degrees
up from midaxillary
cardiac changes in obesity
**can heart handle induction? most stressful part
CO increase for each kg of adipose= increased circulating blood volume which can put strain on myocardium
-cardiomegla, large LV
*CXR and ECG
Arterial HTN risk X2 compared to lean pt
risk for CAD doubled: angina, CHF, acute MI, sudden death
Increased Lsided heart problems and L ventricular hypertrophy
Pre-op determine cardiac tolerance for fat people
have limited reserve for : hypotension tachycardica fluid overload * increase pulm blood ruins RV increased CO ruins LV =BIventricular failure
Hyperlipidema
increased LDL-linked to atherosclerosis decreased HDL-same Can lead to: -coronary art disease -vascular disease -pancreatitis
obstructive sleep apnea
obesity- Independent risk factor 5% obese pt *less than 15% cases are diagnosed characterized by: apena>10sec despite res effort against closed glottis -hypopnea 4%decrease in arterial O2 sat -frequent apnea episodes during sleep: -O2 desat -impaired concentration -snoring -morning HA
Severity of OSA measured by apnea hypoxia index # or hypopneic episodes
diagnosed by at least 5 episode of apnea, hypopnea or both during 1 hr
gradeL mild5-15/hr
moderate 15-30/hr
severe>30/hr
OSA risk factors
middle age male obesity ETOH use drug induce sleep aids abd fat distribution neck girth >17inch men >16inch girl
OSA results in
hypoxemia R heart failure hypercapnia pulm and systemic vasoconstriction polycythemia resp acidosis during sleep arterial hypoxmia systemic HTN pulm HTN
OSA and preop
80-95% undiagnosed Ask about -sleeping patterns -snoring -daytime somnolence **sould identify pts at risk for OSA
obesity and hypoventilation syndrome (OHS) Pickwickian syndrome
extreme obesity
long term complications of OSA
airway difficulty
nocturnal central apenic events
-apnea withOUT resp effort
Theory: loss of pt hypercarbic drive to breathe due to progressive desensitization of res enter
-loss of central medicated response: rain never says wake up and breathe
**should be admitted after surg NOT sent home
OHS characterized
obesity hypercapnia daytime somnlence arterial hypoxemia pulm HTN resp acidosis R heart failure *difficult airway
obesity and thromboembolic
risk for DVT doubled
polycythemia
increased intra-abd pressure
*immobility
obesity and GI
gastro-esophogeal reflex
- hiatal hernia increased risk
- increased gastric volume and intro gastric pressure: emptying delays
- gastic acidity: increased risk for aspiration PNA
- gastic volumes >25
- Ph<2.5–increased parietal cell secretion
Hepatic obesity
fatty liver, abnormal LFT
fluorinated volatile anesthesia
Metabolic obesity
resistance to effect of insulin
adult onset DM
Pre-Op eval obesity
focus on difficulties obesity present to anesthesia provider
likely admit
airway pre-op obesity
hx previous difficulty airway OSA access ROM-neck mouth opening thryomental distance and mallampati interior of mouth **neck size: single best predictor o problematic intubation
fat induction
identify systems of ever resp disease:
-orthopena, OSA, OHA, hx airway obstruction
CXR,
Room air O2sat-preop 92% probable admit
ABG
pull function test- if pronounced diseased
**optimize pulm status pre-op
fat preop CV
signs of HTN, RV/LV hypertrophy, pull HTN IV access ECG CXR--must with fat ECHO, LV ejection fraction--may have cardiac clearance if needed previous diet aids: -epidrine--MUST be off! -phenfen--MUST have ECHO!
fat preop endocrine metabolic and GI
BGL 6 poor control
fat liver preop
weight loss even albs can revers elevated liver enzymes
-fatty infiltration: increased prevalence of nonETOH fatty liver disease
often hace altered histology and LFTs: normal clearance
Preop labs fat
hepatic function
albumin level
glucose
coags- if risk factor
monitor fat
BP cuff correct size iv access pulse ox abg ETCO2
fat positioning
special tables or 2 together
ramp up
max wt per vicky 205kg
strapping pt carefully-skin cponscerns
protect pressure points
consider 2 arm boards
supine—compression of vena cava, FRC and oxygenation decreased
change from sitting to supine–significant change in CO, PAP, O2 consumption
*head up reverse Tberg: provides longest safe apnea period
*prone: increase intra abd pressure, worsen vena cava and aortic compression decreased FRC,
*lateral postion favored over prone!
fat aspiration prophylaxis
pre-op anxiety Tx: H2 receptor antagonist sodium citrate (bicitra) 30ml alkaline Reglan Omeprazole
