Obese Adult and Child Lecture 1 Flashcards
Formula for BMI
weight in kg/ height in meters squared
BMI chart also known as
Quetelet’s index
Morbidly obese is BMI>__ or ?
40; BMI 35-49.9 with obesity related comorbidity
What is a good predictor of cardio respiratory comorbidity?
waist or collar circumference
Another term for IBW is?
Broca’s index
lowest morbidity and mortality for a given population
IBW
IBW in kg formula for men
height (cm)-100
IBW in kg formula for women
height (cm)-105
total body weight minus adipose tissue
lean body weight
Which weight category of individuals do you use lean body weight for?
morbidly obese; not obese
formula for LBW
IBW X 1.3
in nonobese and nonmuscular individuals TVW=?
IBW
in morbidly obese patients, increase IBW by what percent to equal LBW?
20-30%
LBW in morbidly obese is -/- of the difference between IBW and TBW?
1/3
apple shape is also called?
android
pear shape is also called?
gynoid
which body shape has a significant correlation with metabolic syndrome?
android/apple
What are 3 side effects of pear/gynoid shape?
varicose vein development, joint disease, decrease in type 2 diabetes
This type of fat is metabolically static and functions as energy deposits like when pregnant or lactating?
pear/gynoid
man having waist circumference > _ is risk factor?
102 cm/ 40 in
woman having waist circumference > _ is risk factor?
88 cm/ 35 in
What inflammatory mediators are elevated in obese patients?
AGT, transforming growth beta factors, TNF, IL6
most effective tool for long term weight loss?
lifestyle counseling
How does weight loss drug Phentermine work?
sympathomimetic
How does Orlistat work?
blocks the absorption of fat
EBV for obese?
45-50 mL/kg
How much does CO increase for every kg of fat gained?
0.1 L/min or 100 mL/min
an increasead CO is seen as an increase in __? __ remains the same
stroke volume, hr
What are 2 things in obese individual that increase blood volume?
hypoxic induced chronic resp insufficiency and increase in Na retention
In what four ways does the increase in circulating blood volume produce a greater demand on the myocardium?
by increasing metabolic rate, increasing O2 consumption, increasing CO2 production, and normal or slightly abnormal arteriovenous O2 difference
Most confirmatory test of pulmonary HTN with clinical eval?
tricuspid regurg
2 indicators of left ventricular dysfunction?
orthopnea or paroxysmal nocturnal dyspnea
Chronically elevated cardiac output leads to?
ventricular remodeling
6 step cardiovascular pathway in obese person
1- increased preload and stroke work 2- increased left ventricular heart pressures and wall stress 3- left ventricular hypertrophy 4- cardiomegaly 5- atrial and biventricular dilation 6- biventricular hypertrophy
For every 13.5 kg of fat the body regenerates additional __ miles of neovascularization?
25
HTN is defined as SBP> ? or DBP > or both?
140, 90
BP increases __ mm Hg for every 10% increase in body weight?
6.5
What 2 things are released in obese peoples’ blood which increase viscosity?
catecholamines, estrogen
hyper__ increases levels of norepinephrine?
insulinemia
obese ppl have __ or __ levels of SNS activity?
normal or increased
What do increased levels of SNS activity predispose people to (3)?
increased insulin resistance, dyslipidemia, and HTN
For every 10 kg of weight gained, the SBP increases by ? and the DBP increases by?
3-4 mm Hg, 2 mm Hg
What type of effect does norepinephrine have on Na and Ca?
increased renal tubular reabsorption which results in hypervolemia
How does insulin have an effect on Na retention?
it stimulates adipocytes to release angiotensinogen then activates the renin angiotensin aldosterone pathway which leads to further Na retention and progression of HTN
Obese nonhypertensive pt: what happens to SVR, blood volume, and how is the heart dilated?
decreases SVR, increases blood volume and leads to eccentric dilated heart
Obese and uncontrolled HTN heart: what happens?
mixed eccentric/dilated and concentric/ventricular hypertrophy
What does obesity and uncontrolled HTN lead to?
heart failure and pulmonary HTN (dilation and hypertrophy)
Clotting factors elevated in obese pts?
fibrinogen, factor VII, factor VIII, von willebrand, plasminogen activator inhibitor (inhibits breakdown of clots)
how much more of an increase in developing a DVT bc of surgery does an obese pt have versus a nonobese pt?
50%
Why do obese patients have an increased risk of stroke?
prothrombotic and chronic inflammatory state seen with excessive adipose tissue accumulation
1 unit above BMI, there is a __% risk of ischemic stroke and a __% risk of hemorrhagic stroke?
4;6
What happens to elastic resistance and compliance in obese patients?
increased elastic resistance and decreased compliance of chest wall
fat accumulation forces the diaphragm where?
cephalad
Lung volumes that decrease with obesity?
FRC, ERV, VC, TLC
premature airway closure–> _____ –> _______ –> ________
VQ mismatch–> right to left shunting–> arterial hypoxic event
Supine positioning in obese pt reduces FRC up to __% as compared to 20% in non obese patient
50%
most sensitive indicator of pulmonary fucntion
expiratory reserve volume
volume of air present in the lungs at the end of passive expiration; at this the elastic recoil forces of the lungs and chest wall are are equal but opposite and there is no exertion of diaphragm or other muscles
FRC
the additonal amt of air that can be expired from the lungs by determined effort after normal expiration
ERV
3 lung volumes that remain the same in obese pts
residual volume, closing capacity, FEV1/FVC
volume of air still remaining in the lungs after expiratory reserve volume exhaled
residual volume
2 factors that contribute to decreased SaO2 during DL in obese pt
decreased FRC and increased O2 consumption
apnea is defined as (3):
reduction of airflow > 10 seconds, lasting > 15 episodes per hour of sleep, decrease in O2 saturation >4%
gold standard for sleep apnea diagnosis
overnight polysomnography
3 types of sleep apnea
central sleep apnea, OSA, mixed sleep apnea
type of sleep apnea that is respiratory efforts with no flow, periodic, partial, or complete obstruction, usually produced by excess soft tissue; unable to inhale effectively bc airway collapses
OSA
type of sleep apnea that is apnea without respiratory efforts
central sleep apnea
what causes pt to wake up with sleep apnea?
decreased O2 levels
type of sleep apnea that is delayed effort with varying degrees of obstruction
mixed
7 physiologic changes seen from OSA:
hypoxemia, hypercarbia, polycythemia, systemic HTN, pulmonary HTN (mean >25 at rest), right ventricular failure, cor pulmonale (pul HTN and right vent failure)
STOP questionnaire stands for?
Snoring, Tiredness, Observed you stop breathing, Pblood Pressure
BANG questionnaire stands for?
BMI> 35, Age >50, Neck circumference > 40cm, Gender male
High risk of the STOP BANG questionnaire is >__ items?
3
Difference in OHS versus OSA is?
nocturnal periods of central sleep apnea
Diagnosis of OHS (3)?
BMI> 30, daytime hypoventilation, awake PaCO2> 45
Only additional parameter shown to improve ventilation in obese patients?
PEEP
3 negatives of PEEP:
decrease CO, decreased venous return, reduced O2 delivery
2 GI conditions that are increased with obesity?
gallstones and pancreatitis
which sphincter is relaxed in GERD pts
lower esophageal
increased intragastric pressure causes 2 things:
lower esophageal sphincter relaxation (GERD) and hiatal hernia
what happens to the gastric volume and pH in obese pts?
increased gastric volume and pH more acidic
gastric volume > ? and pH
> 25 mL, 2.5
What causes the delay in gastric emptying in obese patients?
increased abdominal mass, decrease in pH
How is gastric emptying affected by obesity?
decreased gastric emptying
elective surgery-obese patients should be given what 3 things?
bicitra, reglan, H2 blocker
elevated lab with nonalcoholic fatty liver disease?
ALT
Pathophysiology behind nonalcoholic fatty liver disease?
increased adipose tissue leads to intrahepatic triglycerides, impaired insulin activity, and release of inflammatory cytokines which leads to destruction of hepatocytes and disarray of hepatic physiology
Severe cases of NAFLD can lead to (3)?
portal HTN, cirrhosis, hepatocellular carcinoma
What happens to thryoid stimulation hormone in obese?
increases and have subclincal hypothyroidism
Why does obesity cause decreased insulin secretion?
pancrease becomes infiltrated with fat
What promotes insulin resistance in obese patients?
enlargement of adipocytes
3 factors that increase wound infection and silent MI?
insulin resistance, hyperglycemia, abnormal glucose tolerance test
One reason surgery increases need for exogenous insulin?
adrenal glands release cortisol in response to surgical stress
3/5 of these is metabolic syndrome
central obesity, HTN, high triglycerides, low HDL, insulin resistance
high triglyceride value?
> 150
low HDL value?
men
insulin resistance is glucose >?
100 or 110
HTN in metabolic syndrome is BP>?
130/85
Metabolic syndrome is associated with what 2 conditions?
diabetes and cardiovascular events
AHA recommended what for metabolic syndrome patients as prophylaxis against events?
low dose ASA
Cancers associated with obesity?
breast, endometrial, colon, kidney, gallbladder, prostate
Most common symptom of pulmonary HTN?
SOB, tired, syncope
Vd of lipid soluble drugs decreases or increases in obese?
increases
is preop assessment of liver function in obese pts recommended?
yes
What happens to weight limitation in reverse positioning?
it is much less
Nerves at increased risk of damage in obese patients?
ulna, brachial plexus, radial, peroneal, and sphenoid
sniffing position-chin higher than?
chest
pharmacology in obese patients-give H2O meds according to what weight and lipid soluble meds for what weight?
H2O LBW and lipid total body weight
lipophilic drugs in obese pt have decreased or increased Vd?
increased, which means that the elimination 1/2 is prolonged d/t large vol of distribution
2 examples of commonly given lipophillic meds in anesthesia?
benzos and barbs
What do you have to be careful about as far as lipophilic meds go in the obese patient?
do not give multiple doses because they will accumulate in adipose tissue and you will see a prolonged effect
What happens to the Vd of hydrophilic drugs in obese pt?
it is unchanged
Nondepolarizing MR are calculated based off of what body weight?
IBW
Suxx is calculated based off of what body weight? Why?
TBW; pseudocholinesterase activity increases in obesity
Why does remifentanyl have limited potential to accumulate in fat tissue even thought it is highly lipophilic?
it is metabolized readily and rapidly by plasma esterase
the newer volatile anesthetics such as sevo and des are more water or lipid soluble?
water
What would a lipid soluble gas mean for emergence?
it would be more likely to accumulate in obese pts and delay emergence
Drugs with extensive extra hepatic metabolism have what kind of pharmacokinetics in obese and lean?
similar-remifent is an example
What kind of body weight do you base propofol induction dose on?
LBW
What kind of body weight do you base propofol maintenance dose on?
TBW
Because obese patients are vulnerable to side effects, how should you figure out the correct medication dose?
typically increase the dose by 20-40% over IBW so that it is based on lean body weight
Loading dose of Fent based on what?
TBW
Recommended rate of Dexmedetomidine in obese pts?
0.2mcg/kg/min
Remifent infusion rates are based on what body weight?
IBW
How many mL of clear fluids is okay 2 hours before surgery?
300 mL
How long should preoxygenation be in obese patient?
5 min
Emergency intubation in obese patient preox should be?
4 VC breaths on 100% FiO2 within 30 seconds of induction
Suxxs dose for RSI in obese?
1mg/kg of TBW
Neck circumference >? is risk factor for intubation?
60
Thyromental distance of what is risk factor for difficult intubation?
EBV in obese patient?
45-55 mL/kg
Restrict use of FiO2 to ? in obese pts during maintenance to prevent ateletctasis?
6 things to improve mechanical ventilation issues in obese pt?
FiO2
Signs/symptoms of anastomotic leak?
tachycardia >120, fever, abdominal pain, shoulder pain (left), SOB, hypotension, hiccups, restlessness
Why are NSAIDs not recommended for post op bariatric pts?
high risk of developing GI bleed
Major post op complication in obese pts?
respiratory failure
Why is there an increased incidence of AFIB in obese pts?
left atrial dilation, increased circulating volume, or left ventricular remodeling d/t ventricular diastolic dysfunction
leading cause of mortality post op in the obese?
PE
interval between surgery and PE is how many days?
13
Most frequent peripheral nerve injuries in obese patients?
ulnar, peroneal, femoral cutaneous
4 risk factors for rhabdomyolysis?
position, duration of surgery, diabetes, BMI> 55
What is one association that is negative between childhood obesity and adverse respiratory events during anesthesia?
bronchospasm
How does maternal obesity affect labor?
first and second stages of labor are longer
2 ways in which a bariatric surgery works?
reduces nutrient intake or reduces absorption
when is bariatric surgery indicated?
if BMI> 40 or >35 with significant comorbidity or severe DM; all non surgical measures tried, psychiatrically stable w/out alcohol or drug dep; committed to long term follow up; BMI>50
2 types of bariatric corrective surgery:
gastric restrictive procedures; restrictive and nutrient malabsorptive procedures
3 types of restrictive procedures?
vertical banded gastroplasty; laparoscopic adjustable gastric banding; lap sleeve gastrectomy
which restrictive bariatric procedure is historic?
vertical banded gastroplasty
which restrictive bariatric surgery is removable and results in shorter hospital stay and fewer complications?
lap adjustable gastric banding
which restrictive bariatric surgery resects the stomach to 20% of its original size?
lap sleeve gastrectomy
type of largely restrictive, mildly malabsorptive surgery?
roux en y
most effective bariatric procedure?
roux en y gastric bypass
this bariatric surgery is when a small gastric pouch is created, which restricts the amount of food eaten and then the distal end is resected and anastomosed to ilium to form common small intestinal limb
roux en y gastric bypass
type of largely malabsorptive, mildly restrictive surgery?
biliopancreatic diversion with duodenal switch
this bariatric surgery is usually done for the super obese
biliopancreatic diversion with duodenal switch
Some problems with the biliopancreatic diversion with duodenal switch surgery?
severe malabsorption, dumping, liver failure, cardiac failure, renal stones
Advantage of biliopancreatic diversion with duodenal switch surgery?
less intestinal SA for absorption to occur
What 2 things do you have to worry about with bariatric surgery in the head up position?
decreased venous return and decreased CO d/t venous pooling in lower limbs
pneumoperitoneum does what to venous return and CO, intra abdominal pressure, and possibly ETT?
decreases venous return and CO; increases intra abdominal pressure and may cause ETT migration
Signs of pneumoperitoneum??
high inspiratory pressures and PEEP
the 5 components of the risk factors scale for obesity surgery?
BMI>50, male, HTN, high risk DVT, age >45
Obese patients may be sensitive to what type of drugs?
lipid soluble
3 affects of hyperinsulinemia?
Na retention, increased blood volume, increased catecholamines
this type of ventricular hypertrophy develops from increased SVR?
concentric
most effective surgical treatment of obesity is?
roux en y gastric bypass
reversal of comorbidities is greatest after which weight loss surgery?
LAGB
this bariatric surgery is mostly formed on the super obese (BMI> 55)
biliopancreatic diversion with duodenal switch
mechanical ventilation using what kind of support (volume or pressure) improves oxygenation in MO pts?
pressure
most common cause of surgically related mortality in bariatric pt surgery?
anastomosis leak
in obese pts undergoing surgery there is some evidence that alveolar recruitment maneuvers in presence of PEEP may improve what 2 things w out adverse HD changes?
oxygenation and respiratory system compliance
pounds and inches BMI formula?
(weight in pounds/height in inches) x 73
how to convert inches to cm
inches x 2.54
hyperinsulinemia is bad for what 2 reasons?
1-increases amts of norepi which cause Na and Ca retention and hypervolemia; 2- adipocytes release angiotensinogen, which activates RAAS and contributes to Na retention and HTN
influencing factors leading to venostasis and DVT?
increased fibrinogen levels, chronic inflammatory state, increased abdominal pressure, immobility, polycythemia
increased adipose tissue causes what 3 things to happen to liver which cause destruction?
intrahepatic triglycerides, impaired insulin activity, and release of inflammatory cytokines
what happens to the Vd of hydrophillic agents in obese pts?
remains unchanged
are muscle relaxants fat or water soluble?
water
Does diabetes increase the risk of rhabdo?
yes
What lab value helps detect rhabdo?
serum CPK
