Obesity Flashcards
Weight Calculations
IBW Ht cm -100 (men) / Ht cm -105 (women). Lean Body Weight (LBW) - also known as adjsuted body weight. LBW = IBW x 1.3 (for obese population)
Obesity Definition
metabolic disorder induced and sustained by overconsumption or under utilization of caloric substrate. Excess body fat puts person at health risk.
BMI Calculations/Categories
Kg/(m)2 / Underweight < 18.5 / Normal 18.5-24.9 / Overweight 25-29.9 / Obese 1 30-34.9 / Obese 2 35-39.9 / Morbidly Obese >= 40
Adipose Tissue Fxns
Endocrine organ / secretes proteins / secretes hormones & inflammatory peptides / reservoir of convertible/usable energy / heat insulation
Body Fat Distribution
Apple shaped/abdo visceral obesity = men / CAD, DM, HTN, DL / fat is metab active, altered metab fxn incr LDL/insulin inh // Pear shaped/gluteal femoral obesity = women / mild vasc problems, joint disease / static metab, unless prego/lactating
Cardiovascular Alteration r/t Obesity
CO must increase to supply blood flow to fat deposits / Increased cardiac workload, CO incr / Develop cardiomegaly/global cardiac dilation & hypertrophy / HTN in 50% (w/ dilated & hypertrophied heart) / normotensive with dilation only to accommodate added blood volume.
Volume Replacement r/t obese pt
Obese patient have reduced water %, severely obese is 40%. Also reduced EBV compared to lean patients. Obese pt has 45-55 ml/kg (ABW, not IBW) compared to 70 ml/kg.
Pulmonary Alteration r/t obesity
Decr CW compliance, decr FRC, hypoventilatory & hypercarbia, increased metab needs increases O2 consumption, decr Vt, Exp Reserve Volumes near zero, Direct inverse relation between BMI and FRC. Incr risk of atelectasis d/t excess compression on small AW.
Measure to maintain pulmonary status
preoxygenate!!! / CPAP / PEEP after induction / Higher FiO2 during case / position change / Tube placement, no mvmt.
Pickwickian Syndrome / Obese hypoventilation
Daytime hypovent with awake PCO2 greater than 45 and sleep disordered breathing in absence of other causes.
OSA
Excessive episodes of apnea > 15 secs. D/t complete or partial AW obs. BMI >35 incidence is near 75%. Hypopnea - 50% reduction in airflowfor 10 secs, >15x per hour (adrenergic surge rescue). Graded by hypopnea index, >30, 16-30, 5-15(mild)
GI/Endo alterations r/t obesity
larger gastric volumes / increased incidence of GERD / Hiatal hernia more prevalent / NAFLD d/t insulin resistance / more prone to Type 2 DM / aspiration risk (RSI usually, no LMA)
Metabolic Syndrome
3 present / Elevated: waist circumference / triglycerides / BP / fasting glucose. Reduced: HDL. Overall increase risk for CAD, stroke, PVD and Type 2 DM.
Skeletal/Integumentary
Increase risk for skin breakdown, excess skin creases/folds, poss poor hygiene. At risk for wound dehiscence / Rhabdo risk / Decr ROM, mobility. Incr risk for thromboembolism.
CV Derangements Cause….
incr blood viscosity / incr catecholamines? / incr estrogen / hyperinsulinemia / excess cortisol/aldosterone / hypercholesterolemia / CAD / Arrythmias
Obese Pre op assessment
Need cardiac eval / CP, exercise tolerance / cxr / 12Lead EKG and poss cardiac w/u
Clinical Resp Alterations
Incr risk of atelectasis (over non obese pt) / Incr AW pressure d/t decr compliance/abdo compression / Incr Vd d/t rapid/shallow brth / chronic hypoxemia –> polycythemia (incr visco) –> incr CAD/CVD risk / poss Pulmo HTN d/t chronic hypoxia/excess pulmo volume
Airway Mgmt of Obese Pt
Proper sniff position / RAMP patient / tragus to sternum alignment / neck circum indicator of diff AW
Regional Anesthesia for Obese Pt
Diff ID of landmarks / positioning may be diff / longer needles required / unpredictable Rx spread / incr BMI = incr upward spread of SA meds
Rx dosing for obese pt
NDMB - based on IBW / Succs - based on TBW / Propofol - based on LBW / Fentanyl - load on TBW, maintenance on LBW
Intra-op and Post op mgmt
Gas choice - use all iso may last longer, turn off sooner / higher FiO2 needs determine N2O use / on emergence need supp O2, suction, CPAP/BiPap / pain control that wont compromise ventilation
