Obesity - Exam 5 Flashcards
Healthy weight is classified as a BMI of:
18.5-24.9
BMI formula:
BMI = wt in kg / (ht in m)^2
OR
BMI = (wt in lbs/ ht in inches^2) x 703
A person’s degree of obesity is defined using _
BMI
Overwt is defined by a BMI of=
25-29kg/m^2
Obesity is defined by a BMI of=
30kg/m^2
Class I obese BMI:
30-34.9kg/m^2
Class II obese BMI:
35-39.9kg/m^2
Class III obese BMI:
> 40kg/m^2
Lean body mass in obese pts is _ % which accounts for extra muscle needed to carry the weight.
30%
-so this means LBW is 30% higher than IBW
Lean body wt (LBW) =
IBW x 1.3
male IBW = Ht in cm -100
female IBW = Ht in cm -105
What kind of organ is adipose tissue? What does it secrete?
Endocrine; proteins
What are the main functions of adipose tissue?
- Reservoir of energy
- Maintain heat insulatio
What results from liver fat metabolism?
Fatty acids –> energy
Triglycerides from carbohydrates and proteins
Phospholipid and cholesterol synthesis
Why is fat a good insulator?
Fatty acid chains in fat cells shorten with long-term cold exposure –> becomes more unsatruated –> does not get metabolized because only liquid fat can be metabolized
T/F All cells contain some saturated fats made by the liver
False, UNsaturated
Fat cells arise from modified _
fibroblasts
Mechanism of obesity (physical change) children vs adults
Children become obese due to increased fat cell #
Adults become obese due to enlarged fat cells
Apple body hip/waist ratio associated with comorbidities in men and women?
0.85 men < x (nagelhout)
0.92 women < x (nagelhout)
> 1.0 (men/women) bad
Waist circumference associated with increased comorbidities?
> 40 in men
35 in women
Waist:Hip ratio is calculated by dividing the _ waist measurement by the _, and is taken while the pt is _
narrowest
broadest
standing
pear body hip/waist ratio associated with comorbidities?
<0.76
What’s better, pear (gynecoid) or apple (android), why?
Pear (gynoid)
Fat stores in gynecoid do not release FFAs (they are metabolically static)
Android fat stores release FFAs –> to liver –> LDL/VDL creation
Which body system is the primary cause of morbidity and mortality associated with obesity?
CV
-HTN
-Ischemic heart disease
-CHF
CO goes up by how much per kg of fat?
0.1 L/min
How to assess for abdominal obesity?
Waist:Hip ratio
Underweight BMI:
<18.5
Normal BMI:
18.5-24.9
Overweight BMI:
25-29.9
Obese (Class I) BMI::
30-34.9
Obese (Class II) BMI:
35-39.9
Obese (Class III) BMI:
> 40
_ fat distribution is metabolically static and proposed to work as energy deposits for pregnancy and lactation
gynoid/pear
_ fat distribution is metabolically active regarding free fatty acid release
Android/apple
It is possible that hyper_ alone may cause HTN
hyperinsulinemia
Adipocytes are known to produce and store several inflammatory mediators such as: (4 items)
-leptin
-TNF-alpha
-monocyte chemotactic protein
-IL-6
Number one cause of morbidity and mortality associated with obesity:
cardiovascular disease
For every 13.5kg of fat gained, an estimated _ miles of neovascularization is created to provide blood flow rate of - mL/100g of tissue
25 miles
2-3mL/100g
increases CO by 0.1L/min per kg of fat gained
Cardiovascular changes with obesity (non-specific pathologies, not physical changes)
Increased CO
Increased O2 consumption
Increased CO2 production
Increased blood volume
How much does BP increase per 10% increase in body weight
6.5 mmHg per 10% body weight increase
How does obesity activate RAAS?
Fat compresses the kidney, stimulating the sympathetic nervous system , also impairs sodium excretion
What is hypercholesterolemia?
> 240 mg/dL
How do respiratory parameters change with obesity?
Decreased:
FRC
ERV
TLC
Increased:
Dead space
CO2 retention
(Restrictive lung disease)
What is the relationship between BMI and FRC?
FRC exponentially decreases
Respiratory changes in obesity lead to what risk factors cardiovascularly?
Chronic hypoxia –> polycythemia –> CAD/Stroke
Definition of OSA?
apnea during sleep longer than 10 seconds despite ventilatory efforts, 5+ more times/hr of sleep, decrease in SpO2 > 4%
What is hypoapnea?
50% reduction in airflow for 10 seconds, 15 + times during an hour of sleep
5-15 mild
15-30 moderate
Which muscles dilate/contract the pharyngeal airway?
Intrapharyngeal –> contract/collapse
Pharyngeal –> dilate
What keeps your airway open as you sleep?
Tensor muscles via CNS
Pathophysiology of sleep apnea?
Multifactorial causes (neural, physical obstruction, mechanical issues) –> Upper airway collapse –> pharyngeal dilator muscle activity surge –> hyperventilation –> decreased CO2 –> decreased respiratory drive –> repeat
Increased vagal tone is associated with…(increased/decreased OSA?)
increased OSA
Gold standard OSA diagnosis
Overnight PSG
What is Pickwickian syndrome?
AKA Obesity hypoventilation syndrome (OHS)
-Most severe form of OSA
-Hypercapnia (sleep-disordered breathing not due to other syndromes)
-NO respiratory effort
-Hypersomnolence during the day
-Cyanosis-induced polycythemia
-Respiratory acidosis (Pa CO2 > 45)
-Pulmonary HTN
-R sd HF
-Dependent edema
-Obesity (BMI > 30)
Which component of CO causes its increase in obese individuals: HR, SV, or both?
SV
-this causes cardiomegaly, bivent hypertrophy, and atrial and biventricular dilation -> HTN -> CHF
Factors influencing increase in HTN with obesity:
-increased blood viscosity
-altered catecholamine kinetics
-increased estrogen concentration
-hyperinsulinemia
-elevated mineralcorticoids
-abnormal sodium reabsorption
-RAAS activation
-increased SNS activity
Thoracic _ (kyphosis/lordosis) and lumbar _ (kyphosis/lordosis) result in impaired _ movement and fixation of the thorax in an _ (inspiratory/expiratory) position
Thoracic KYPHOSIS
Lumbar LORDOSIS
rib
inspiratory
Chronically elevated CO precedes increased _ (right/left) sd heart pressures and _ (right/left) vent hypertrophy
left
left
Skeletal changes from obesity such as kyphosis and lordosis cause a _ (increase/decrease) in chest wall, lung, parenchyma, and pulmonary compliance of about 35%
decrease
Which 2 factors regarding obesity cause an increase in myocardial O2 consumption?
-metabolic needs of fat tissue
-greater mechanical WOB
Which factors cause increases CO2 production and retention in obese pts?
-reduced respiratory muscle efficiency
-decreased ventilation
Reductions in chest wall and lung compliance in obese pts cause a _ pattern of breathing
restrictive
In obese pts, lung inflation is _ causing a decrease in FRC to _ than closing capacity.
inhibited
less
Premature airway closure in obese pts causes: (5 items)
-increased CO2 retention
-increased dead space
-VQ mismatch
-shunting
-hypoxemia
EXTREME obesity is associated with reductions in which 3 respiratory parameters?
-FRC
-expiratory reserve volume (ERV)
-total lung capacity
(also decreasing vital capacity)
Rapid, shallow breathing seen with obese pts is characteristic of _ lung disease. These patterns will eventually burn out, causing a _ in CNS responsiveness to chronic hypoxia. This leads to _ventilation and respiratory _ (alkalosis/acidosis)
restrictive
decrease
hypoventilation
acidosis
Recurrent hypoxemia leads to secondary _
polycythemia
-increases risk for CAD and CVA
Apnea is the cessation of airflow at the nose/mouth for > _ sec
10 sec
Hypoponea characteristics:
-50% drop in airflow for 10 sec
-happens 15+ times / hr of sleep
-assoc with snoring and 4% decrease in O2
OSA is diagnosed by _ using an apnea-hypopnea index (AHI)
polysomnography (PSG)
-AHI is # of abnormal respiratory events during sleep
Minimum DIAGNOSTIC criteria for OSA:
AHI of 10
WITH
symptoms of excessive daytime sleepiness
Diagnostic criteria for OSA per the American Academy of Sleep Medicine
Mild OSA:
Moderate OSA:
Severe OSA:
Mild: 5-15 AHI
Mod: 15-30 AHI
Severe: >30 AHI
Minimum MEDICARE criteria for OSA:
-AHI of 15
OR
-AHI of 5 WITH 2 comorbidities
T/F CAD is a risk factor for obesity
false, it is independent
Genetic factors involved with obesity:
-Prader Willi Syndrome
-Baret Biedl Syndrome
-Obesity “hormone” LEPTIN (not enough -> overeating)
Diseases that can CAUSE obesity:
cushings, PCOS, hypothyroidism
T/F FRC is directly proportional to BMI
false
INVERSELY (increased obesity = decreased FRC)
Physical factors related to OSA that increase as obesity increases:
-BMI > 30
-abdominal fat distribution
-neck girth (men >17inches ^2, women >16inches^2)
The site of upper airway obstruction is usually the _
pharynx
Patho of OSA:
1.While awake, patency is maintained by mediation of contraction of the _ muscles in the CNS
2. Then, _ muscles oppose the neg inspiratory forces that collapse them
3. While asleep, these muscles relax and cause the soft-walled _ to collapse between the _ and _
4. The resulting hypoventilation triggers a surge of _ dilator muscle activity, which opens the airway then causing _.
5. _ reverses the hypercarbia, which reduces the _ drive to breathe again. This is a vicious cycle.
- tensor
- dilator
- oropharynx, uvula, epiglottis
- pharyngeal, hyperventilation
5.Hyperventilation, CNS
this causes fluctuating hypercarbia and hypoxia, poor sleep, and triggers adrenergic output with each cycle
HR abnormalities associated with OSA:
-bradycardia
-sinus node dysfunction
-asystole
_ or more clinically significant apneic episodes per hr or > _ episodes per night cause hypoxia, hypercapnia, systemic and pulmonary _, and cardiac _
5 times/hr or 30 times /night
systemic and pulm HTN
cardiac arrhythmias
STOP BANG =
Snoring = do you or others think you snore
Tired = daytime tiredness/fatigue
Observed = anyone witnessed apnea
blood Pressure = treatments for HTN
BMI >35
Age >50yo
Neck circumference >40cm
Gender = male
-high risk OSA = yes to 3+ items
-low risk OSA = yes to <3 items
Things to ask obese pts regarding OSA even without a diagnosis:
-sleeping patterns
-snoring
-apnea
-arousals thru night
-daytime sleepiness
-OSA is significantly UNDERdiagnosed
Preop methods to reduce OSA concerns
-individualized anesthetic planning tailored to comorbidities
-preop consults for other coexisiting conditions with obesity (PSG, endocrine, etc)
-minimal or no sedation if possible, premedication with precedex to minimize opioid needs
Intraop methods to reduce OSA concerns
-regional blocks if appropriate
-ramping to enhance preoxygenation, airway visibility, and pt comfort
-CPAP in preoxygenation phase
-ASA difficult airway algorithm
-minimize/ avoid opioids
-short acting agents if possible
-regional/ multimodal analgesia (NSAIDs, tylenol, tramadol, ketamine, gabapentin, pregabalin, dexamethasone)
-propofol for maintenance
-sevo or desflurane (quick on/off - less soluble)
-CAPNOGRAPHY
Reversal of anesthesia methods to reduce OSA concerns:
-verify full reversal of NMB
-fully awake/cooperative before extubation
-semi-upright angle for extubation/recovery
Postop methods to reduce OSA concerns:
-CPAP and supp O2
-avoid opioids
-intense respiratory monitoring
-VTE proph
-local/regional techniques for outpt surgeries
-transfer arrangements available for inpatient admission if needed
-longer monitoring period in PACU
T/F Pickwickian/ OHS is associated with elevated bicarb levels.
TRUE-in early stages!!
normocapnia, base excess and high bicarb while awake due to chronic hypercapnia during sleep
OHS/Pickwickian is diagnosed when:
PCO2 is >45mmHg during wakefulness with compensatory hypoxemia (PO2 <70mmHg)
-symptomatic obese pts are screened for diagnosis
asymptomatic obese pts with only hypoxia but all other parameters WNL are not screened
Which respiratory condition is associated with cardiac enlargement, cyanosis, polycythemia, and twitching in obese pts?
Pickwickian/ OHS
Early diagnosis of OHS/Pickwickian is achieved by review which 2 labs while the pt is asleep?
-ABG
-base excess (elevated bicarb)
4 GI conditions associated with obesity
-GERD
-gallstones
-pancreatitis
-NAFLD (steatosis, steatohepatitis, fibrosis, cirrhosis, hepatomegaly, abnormal liver biochemistry)
What causes alveolar ventilation to reduce in obese pts?
-shallow and inefficient ventilation
-decreased Vt
-poor respiratory strength
-poor elevation of diaphragm
Most common liver condition worldwide?
NAFLD
-confirmed with liver biopsy
NAFLD increases the risk for:
-cirrhosis
-hepatic decompensation
-hepatocellular carcinoma
Gallstone formation in obese individuals occurs due to high concentrations of _ in the bile and high ratios of bile salts to _
cholesterol
lecithin
Weight gain with _ obesity is a major predictor of metabolic syndrome
visceral
Metabolic syndrome consists of an array of disorders :
-glucose intolerance
-T2DM
-HTN
-dyslipidemia
-CV disease
Patients with metabolic syndrome exist in a pro- _ and pro- _ state.
pro-inflammatory
pro-thrombotic
AHA Metabolic Syndrome Diagnostic criteria:
3 or more of following:
-elevated waist circumference (men 40inches+, women 35 inches+)
-elevated triglycerides (150mg/dL +)
-reduced HDL (men <40mg/dL, women<50mg/dL)
-high BP (130/85+)
-high fasting BG (100mg/dL +)
Joints commonly affected by OA from obesity:
-ankles
-hips
-knees
-L spine
How can limited activity lead to the development of fractures?
bone resorption from immobility causing loss of bone density and contributing to stress fractures
Pediatric obesity is recognized as a BMI > the _ percentile on the CDC growth chart.
95th
T/F Obesity can slow gastric emptying and cause a reduction in gastric pH
true
T/F Obese kids have a higher risk of being obese as an adult and have higher risks of developing comorbidities throughout their lives.
true
Most significant link to increases in birth weight:
maternal obesity
NOT diabetes
Obesity causes which stages of labor to last longer?
1st and 2nd
Americans of which descent are at higher risk of developing T2DM as children?
African, Hispanic, Asian, and Native American
T/F Prepregnant obesity greatly increases the risk of needing a CS
true
Pregnancy outcomes that are complicated by obesity:
Preeclampsia (heightened risk with metabolic syndrome)
gestational diabetes (GDM)
CS and instrumented deliveries
preterm labor
postpartum hemorrhage (PPH)
infection
pregnancy-induced hypertension(PIH)
macrosomic infants (weight >4kg)
difficult neuraxial placement
difficult intubation
The first _ wks of pregnancy have increased risk of spontaneous abortion and miscarriage in obese women.
6wks
Drug classes for long-term obesity treatment:
Sympathomimetic Amines
-Benzphetamine, Phentermine
Sympathomimetic Amines/AntiEpileptic combo
-Phentermine/Topiramate ER
Lipase Inhibitors
-Orlistat
Serotonin Receptor Agonist
-Lorcaserin
Opioid Antagonist/Antidepressant combo
-Naltrexone/Bupropion
GLP-1 Receptor Agonists
-Liraglutide, Semaglutide (Ozempic, Wegovy), Terzepetide (Mounjaro)
Indications for bariatric surgery:
Must meet all the following:
-BMI >40 or <35 with accompanying comorbidities
-Failed dietary therapy
-Psychiatrically stable with no alcohol dependence or illegal drug use
-Understand the operation and its sequelae
-Motivated patient
-Other medical issues do not significantly add to surgical risk
MOA of Bariatric Surgeries
RESTRICTIVE
-Vertical banded gastroplasty (VBG-older)
-Lap adjustable gastric banding (LAGB)
-Lap sleeve gastrectomy (LSG)
MOSTLY RESTRICTIVE, MILDLY MALABSOPTIVE
-Roux-En-Y gastric bypass (RYGB)
MOSTLY MALABSORPTIVE, MILDY RESTRICTIVE
-Biliopancreatic Diversion (BPD)
-Duodenal Switch (DS)
bold = most common
Procedure of choice for clinically severe obesity:
Roux-en-Y gastric bypass
Drug therapy for obesity can begin once BMI > _ or if it is _ - _ with comorbidities
> 30 or 27-29.9
Common approach for dosing medications and obesity is to give water-soluble drugs based on _ and lipid-soluble drugs based on _
Water-soluble: ideal body weight IBW (adding 30% to this accounts for the increases in lean body mass)
Lipid-soluble: total body weight TBW
Best volatile anesthetics for obese pts:
Sevo + Des
-adding N2O helps reduce these doses too while reducing postop pain - just give antiemetics with it
Dosing changes of IV agents in Obese Pts:
Propofol = induce with LBW , maintain with normal wt
Sux= intubate with normal dose
NDMR(Roc, Vec, Cisatracurium)= All doses via IBW
Fentanyl + Sufentanil = normal loading dose, maintenance via LBW and response
Remifentanil= infusion via IBW
Precedex= infusion rates of 0.2mcg/kg/min
Sugammadex=normal wt doses
Medications that are dosed via TBW (normal wt)=
Prop (maintenance)
Sux
Fentanyl + Sufentail (LOADING dose)
Sugammadex
Medications dosed using alternative wts=
LBW:
-Prop(induction)
-fentanyl+sufentanil (maintenance)
IBW:
NDMR (roc, vec, cisatracurium) (all doses)
Remifentanil (infusions)
Lower rate altogether:
-Precedex (adjunct infusion 0.2mcg/kg/min -minimize cardiac effects)
Preop lab tests considered routine for obese pts:
EKG + glucose check
Preop considerations for obese pts:
-herbal, weight reducing, or anorexiant drugs
-abx + VTE proph
-OSA symptoms, sputum, smoking, URI
-eval for masking or airway difficulty
Outside of clinical exam, which test is the most confirmatory for pulmonary hyptertension?
Tricuspid regurg results on a 2DE
3 strongest predictors of difficult intubation in obese pts:
-MP >3
-increased neck circumference
-hx OSA
Neck circumference measurements:
normal
high risk difficult intubation
higher risk difficult intubation
normal: 35cm
high risk: 40cm
higher risk: 60cm
Factors indicating need for fiberoptic intubation:
-poor mouth opening
-presence of neck or arm pain
-inability to place head in sniff position
GLP-1 agonist considerations:
pts usually need to stop medication for at least 1 wk, and still may require RSI
-US is the only way to confirm gastric content
Pharmacokinetic changes with obesity:
Increased:
-fat mass
-CO
-blood volume
-LBW
-renal clearance
-volume of distribution for lipid-soluble drugs
Reduced:
-total body water
-pulmonary function
Altered:
-plasma protein binding
-liver function
Postop complications of bariatric surgery(Anastomotic Leak)
-s/s
-unexplained, possibly asymptomatic tachycardia (>120) #1
-fever
-abd/pelvic pain
-tachypnea (w/ desat = sepsis?)
-L shoulder pain
-substernal pressure
-HoTN
-SOB
-thirst
-restlessness
-hiccups
-oliguria
Toradol increases the incidence of this
OR prep for obese pt:
-ensure bed is compatible with pt wt
-larger straps, stirrups, arm boards, Bairhugger sheets, etc
-BP cuff on forearm ~ok, but will OVERestimate bp; switch to A-line if dicey
-diff airway cart nearby multiple sizes of equipment (LMAs too)
-5 lead EKG if cardiac hx
-blankets/foam/pillows for ramping
BP cuff must encircle a minimum of _ % of upper arm circumference
75%
-FA cuff pressures will be HIGHER than actual, ok unless unreliable readings - > A line
GERD considerations in obese pts:
-recent gastric banding = increased asp risk
-check gastric US, if < 1.5mL/kg = low risk asp
-RSI ready
- aspiration proph measures (H2 blockers, PPI, cric pressure-maybe)
-opioid sparing if poss
Positioning for intubation in obese pts:
-sniffing or ramped
“HELP” head-up-laryngoscopy position reminds us of positioning importance
-reverse trend a bit (better FRC, better view)
-want head, neck, and shoulders greatly elevated above chest imaginary horizontal line connecting sternal notch and external auditory meatus
T/F Obese pts need to fast longer than nonobese pts
false
same fasting time, can have up to 300ml of clear liq up to 2hr preop
When to do awake or propofol only intubations in obese pts:
-if BMI > 50 or lower with high risk factors of OSA or large neck circumference
Which has a higher incidence of postop nausea, gastric sleeve or gastric banding?
sleeve > banding
T/F If DL doesn’t work, LMA certainly won’t work for obese pts
false, may help establish airway immediately
Goal of cricoid pressure:
occlude esophagus between cricoid cartilage and vertebral body, reduce risk asp(debatable), better view of cords
Preoxygenation of obese pts:
100% mask O2 for 3-5 min with CPAP as tolerated
-v important bc of reduced FRC and increased O2 consumption, reduces atelectasis while laying flat and increasing PaO2
-alternatively HFNC O2 can help prevent desat pre intubation
Modified RSI:
-preoxygenate with cricoid pressure
T/F The surgeon or another skilled anesthesia provider MUST be in attendance during intubation
true
How to manage muscle hypotonus in lower mouth, and soft tissue obstruction with hypoxia in obese pt during induction:
2 person mask/vent technique
How to improve FRC and arterial O2 tension in an anesthetized obese pt:
PEEP!
-costs CO and O2 delivery tho
-GA reduces FRC 50% in obese pts
Optimized vent settings for obese pt:
-Vt= 6-10mL/kg of IBW avoids barotrauma
-pressure or volume control ventilation
-get ABG if SpO2 <95% during induction to assess for OHS/Pickwickian
-RR 12-14 for lap cases
-PEEP 10-12cmH2O -prevent/reverse atelectasis
-keep end-inspiratory pressure<30cmH2O
-mild permissive hypercap
-use at least 50% FiO2 but aim for less than 80%
-use recruitment breaths/intermittent sighs
Potential problems with longer cases and cases involving the abdomen,spine,thorax:
-recumbent position decrease FRC and increase filling pressures of heart on R sd, increases CVP
-higher myocardial O2 consumption, CO, PAOP, PIP, increased venous admixtures above sitting value (give PEEP to fix this)
Methods to maintain postop lung expansion:
-CPAP/BiPAP immediately after
-Supp O2 PRN
-Upper body elevated is poss
-pain control
-incentive spirometry
-early ambulation
-monitor pt for 24 hr postop if appropriate
FRC can briefly be improved with large Vt - mL/kg but only minimally improves arterial O2 tension
15-20mL/kg
Intraop factors that can decrease alveolar ventilation, cause atelectasis, and pulm congestion:
-subdiaphragmatic packing
-cephalad displacement of organs
-surgical retraction
What can cause cardiopulmonary decompensation intraoperatively in severely obese pts?
-PEEP (decreases venous return)
-inability to raise CO
-this causes vent ectopy, HoTN, hypoxia, rales, and CHF symptoms = try to bag the pt by hand to reduce PEEP and fix HoTN
PEEP of > _ cmH2O should be avoided.
15
-can actually impair oxygenation when given with large Vts
Risks leading to postop respiratory compromise:
-hemorrhage intraop
-hypotension intraop
-vertical abdominal incision
-poor pain mgmt (reduces diaphragmatic excursion, vital capacity, potential atelectasis and VQ mismatch)
What is a recruitment/vital capacity breath?
sustained pressure of 35-40cmH2O for 8-10 sec
helps improve FRC and prevent atelectasis
monitor for bradycardia or HoTN when doing this
Anesthetic choice considerations in obese pts:
-shorter acting meds if poss
-avoid residual NMBD, use sugammadex and TOF
-multimodal approaches (pain, anesthesia, PONV) - lidocaine, ketamine, precedex
-epidurals for postop pain?
-optimize O2
T/F Estimated blood volume is increased in obese pts
false
decreased!
What changes should be made when calculating EBV in obese pts?
Use 45-55mL/kg !!!! not 70mL/kg
Fat is _ - _ % water so it contributes _ fluid to total body water compared to equal amounts of muscle
8-10%
less
Normal adult total body water =
Obese pts total body water =
60-65%
40%
T/F Fluid management and blood replacement strategies are different in obese pts
false
-go by BP, HR, UO as usual
-replace blood as usual
Renal failure risks for bariatric patients:
-hypovolemia
-BMI>50
-prolonged case
-intraop HoTN
-preexisiting disease
Hetastarch must not be given more than _ mL/kg of IBW
20mL/kg IBW
-dilution coags, factor VIII inhibition and platelet aggregation reduction from excess admin
-use albumin as indicated
T/F We want to enhance lordosis when obese pt is on OR table
true!
-use towel/blanket to support lower back lordosis so they don’t have to lay completely flat
Extubation consideration for obese pt
-be ready to reintubate asap if needed (positioning and equipment ready)
-have OPA, exchange cath, pt sitting up if poss
-safest method = AWAKE emergence!
Regional considerations for obese pts:
-may need longer Touhy needle (>7in)
-generous lidocaine (may need multiple attempts, numb well!)
-kinda unpredictable to determine spread (higher rate of epidural failure and resp complication from high regional blk)
How to prevent cephalad/rostral spread in obese pts receiving regional:
-less LA
-more time sitting upright
Max decrease in PaO2 in obese individuals occurs _ - _ days postop
2-3
Most common cause of postop mortality after bariatric surgery in obese individuals
Thromboembolism
Rhabdo risks for obese pts following bariatric surgery:
-male
-old
-elevated BMI
-prolonged operation
diagnostic: CPK levels
Rhabdo treatment:
hydration with goals to avoid:
-hypovolemia
-aciduria
-tubular obstruction
-free radical release
bicarb admin
mannitol
VTE risk factors in obese pts:
-BMI >60
-venous stasis disease process
-OHS
-OSA
-previous PE
VTE risk prevention in obese pts:
-heparin 5000 units subcut twice daily
-antiembolic stockings
-SCD
-early ambulation
-IVC placement preop
Pulmonary compliance decreases by _% in obese individuals
35%
What is the relationship between BMI and FRC?
FRC exponentially decreases
Which muscles dilate and contract the pharyngeal airway?
Intrapharyngeal: contract / collapse
Pharyngeal: dilate
What keeps your airway open when you’re asleep?
tensor muscles via CNS
OSA is associated with _ (increased/decreased) vagal tone
increased
Calories in fat (1g)
Calories in protein (1g)
Calories in carbs (1g)
fat= 9 cal
protein = 4 cal
carbs = 4 cal
What is leptin?
a hormone made by adipose cells that act as satiety factor in regulating appetite
Is insulin pro or anti inflammatory?
Anti-inflammatory
What is NASH?
Non-alcoholic steatohepatitis
-involves lobular inflammation and fibrosis and is the inflammatory version of NAFLD
Postop lung problems with obese pts
-atelectasis
-hypoxemia
-increased pulm workload
-vital capacity decreases
Worst position for obese pts :
supine
PACU monitoring for obese pts:
-3hr longer before DC home
-7 hr longer if there is a room air apneic episode
Why does CO increase with fat?
fat requires vasculature
How does obesity cause HF?
Diastolic dysfunction
Increased CO -> dilates heart -> walls thicken to push back on pressure -> reduces compliance -> dilates beyond the ability to increase wall thickness -> systolic dysfunction -> biventricular heart failure
Mendelson’s Criteria:
gastric volume > 0.35mL/kg TBW
Which drugs are highly lipid soluble?
Barbiturates, benzos
-remifentanil has no change in distribution
Which drugs are weakly lipid soluble?
propofol, roc/vec, sugammadex
Single biggest predictor of diff intubation in extremely obese pt:
neck circumference
5% = 40cm neck
35% = 60cm neck
normal neck = 35cm
Should you RSI obese pts (if no other risk factors)?
no
only if other risk factors present like GERD
Should RR be set higher or lower for obese pts?
higher
What happens with inspiratory pressure for obesity?
increases
-decreased pulmonary compliance
When to paralyze pt for awake intubation?
after tube placement is confirmed
Criteria for extubation in obese pt:
-Vt/RR at preop level
-VS at preop level
-VC more than 2x Vt
-head lift 5 sec
-NIP 25-30cm
-SpO2 at preop level
-normocapnia
Qualification for bariatric surgery:
-under 65
-100lb over IBW
-other methods failed
-psychologically stable
-loss of 40-60% of wt
-monitored for 5 yrs
What is the Roux-en-Y bypass?
takes part of jejunum and attaches it further up in stomach (bypasses rest of stomach)
Pathogenesis of NAFLD is associated with:
insulin resistance
What symptoms do you expect to see in men and women with endocrine mediated obesity?
-menstrual issues
-decreased libido/impotence
-low serum follicle stimulating hormone and testosterone levels
Gynecoid fat distribution is associated with which obesity related disorder?
Metabolic syndrome
Metabolic syndrome and pregnancy increases risk of which 2 peripartum disease
preeclampsia
diabetes
Which EKG changes are seen in obese pts?
Low voltage
-axis deviation and atrial tachyarrhythmias are common
-QT prolongation could be a sign of LVH -> get 2DE asap, this is a red flag for potential arrest!
