Apex- Obesity Flashcards
Each gram of the following produces how many calories:
-Fat:
-Carbs:
-Protein:
-Fat: 9
-Carbs & Protein = 4
T/F: childhood obesity is more common than diabetes, cystic fibrosis, and all cancers
TRUE! yikes
what % of children and adolescents are overweight or obese?
adults?
over 30%
adults - over 33%
2 genetic disorders associated with obesity
- Prader-Willi syndrome
- Bardet-Biedl syndrome
Where does obesity rank in the cause of preventable deaths in America?
Second (smoking first)
Which is worse: Android obesity or gynecoid obesity?
which is more common in men vs women
which one is apple vs pear shaped
Android obesity worse
men
apple
waist size > what for men vs women is associated with increased risk of ischemic heart disease, HTN, HLD, insulin resistance, and death?
> 40” for men
35” for women
women of course have to have the smaller waist
Metabolic syndrome parameter:
Fasting Plasma Glucose
> 110
Metabolic syndrome parameter:
Abdominal obesity (men vs women)
> 40” wasit in men
35” waist in women
Metabolic syndrome parameter:
Serum HDL (men vs women)
Men < 40g/dL
Women < 50g/dL
Metabolic syndrome parameter:
Serum triglycerides
> 150mg/dL
Metabolic syndrome parameter:
Blood pressure
> 135/85
People with metabolic syndrome have what % greater CV risk compared to the general population
metabolic syndome AKA
50-60%
syndrome X
T/F: diagnosis of metabolic syndrome requires at least 2 of the parmaters
fasle 3
out of 5
fasting glucose > 110
waist > 40” men >35” females
HDL < 40 men, > 50 women
Tris > 150
BP > 135/85
BMI ranges
*just focus on memorizing what each one starts at , starting with normal
normal = 18.5
overweight = 25
class 1= 30
class 2= 35
class 3 >/0 40
Kid %tiles for overweight, obese, vs severely obese
overweight - 85th
obese 95th
severely obese 99th
BMI calculation and the tricky part to it
Weight (kg)/ Height (m2)
tricky part is finding the meters squared
your going to want to convert height from inches to cm ( in x 2.54) - you know this part
then convert cm to meters (cm/100)
*i thinki get tripped up here bc i think i wanan x it but just think dividing will get you a smaller number and meters is a smaller number compared to cm
-then times the cm by itself to square it
BMI of a patient who weights 176lbs and 74 inches tall
22.64
- convert pounds to kg (lb/2.2)
- convert height to cm (in x 2.54)
- convert cm to m (cm/100)
- square the m (mxm)
- KG / m squared
*avoid rounding until you get final answer
BMI of a patient who weights 176lbs and 74 inches tall
22.64
- convert pounds to kg (lb/2.2)
- convert height to cm (in x 2.54)
- convert cm to m (cm/100)
- square the m (mxm)
- KG / m squared
*avoid rounding until you get final answer
Normal child body weight percentile
< 85%
overweight = > 85%
obse = > 95%
severely obse 99%
Ideal body weight calculation men vs women
Men = height (cm) - 100
Women = height (cm) - 105
think 100 = ideal and men are always first
then minus an extra 5 bc women are generally shorter
What measurement of weight describes the optimal weight for a given height
ideal body weight
IBW of a 5’4” man
62.56kg
64 inches x 2.54cm = 162.56cm - 100
you always hate when the height is written in CM for the anesthesia post op- how can you use this to your benifit?
easy way to find out IBW!!!
-100 for men
- 105 for females
wow it took me almost 2 years of clinical to figure that out
i even bought a badge with IBW for all heights - dear god
pt’s height is 170cm (man)
what range do you want their tidal volumes?
IBW = 70kg
tidal volumes = 6-8ml/kg
420-560mls
what’s the IBW of a 5’10” woman ?
72.8kg
70inches x 2.54cm = 177,8cm
177.8 - 105 = 72.8kg
Which factors are reduced by obesity? (select 2):
-vital capacity
-ERV
-closing volume
-residual volume
vital capacity and ERV
obesity creates a RESTRICTIVE ventilatory deffect
–> lungs are compressed and therefore lung volumes are reduced (VC, ERV)
-FRC decreases (bc of ERV)
-RV remains constant
-closing volume increases (collapsing of alvoli)
-vital capacity decreases (decreased ERV)
how does obsity affect FRC, ERV, and RV?
FRC is reduced primarily due to a reduction in ERV
RV remains constant
General Anesthesia causes FRC to fall by what % in obsese vs non-obese population
50% obese
20% non-obese
*obesity = higher o2 consumption + smaller FRC + 50% reduction in FRC with induction = reapid desat
Okay so you know that for fat people, their tidal volume needs to be based on IBW - bc just bc they are fat, doesnt mean their lungs are bigger; however, what else do you need to be aware of with vent settings?
that you will need to increase RR to compensate for increased O2 consummption and CO2 production since fat is a metabolically active organ
What lung volumes (1) and lung capacities (3) are affected by obesity?
decreased ERV
decreased: FRC, VC, TLC
does obesity created an obstructive or restrictive ventilatory effect?
restrictive
lungs are compressed by chest fat and abdominal contents - reduced compliance
T/F: although the abese patient may experience hypoxemia, the PaCO2 is usually normal
True
elevated CO2 signals impending resp failure
explained by the high diffusing capacity of Co2 and the favorabile characteristics of the Co2 dissociation curve
sure….
so i guess they are saying that more alvoli may be compressed and o2 may not be able to diffuse into the blood bc of it, however, bc they have an increased co2 production + it’s ability to diffuse - it balances out
What kind of breathing pattern is good for an obese person and why?
rapid and shallow breaths
they have increased o2 requirements bc fat is metabolically active
& increased weight on the chest increases work of breathing, so rapid shallow breaths provides the most energy- efficent way to achieve this goal
How should you preoxygenate the obese patient?
CPAP 10cm H20
+100% fio2 - duh; until eto2 > 90%
How should you breathe for the obese patient
rapid , shallow breaths
TV 6-8ml/kg IBW
Is it better to manage PaCO2 in the obese patient by increasing the respiratory rate or tV?
respiratory rate
general population is tidal volume bc increasing RR just increases dead space ventilation
however, fat is a metabolically active organ with higher o2 consumption, and the most metabolically efficient way to do this in the obese patient is to increase RR
How to decrease risk of post-induction atelectasis in the obese patient
lower fio2 < 80%
ARMs and PEEP
Optimal positioning of an obese person during induction and why
HELP positon - Head Elevated Laryngoscopy Position
Reverse T & ramp until sternal notch in line with external auditory meatus
*Goal is to elevate the head, shoulder,s and upperbody above the chest
*sternal notch in line with external auditory meatus
You induce anesthesia on an obese patient and sucessfully intubate them and confirm placement - what should you do before putting them on the vent
recruit collapsed alveoli by giving a breath to 40cm h20 and holding for 10 seconds
then apply PEEP to keep them held open
*may reduce venous return and bp (and hr during valsalva)
T/F: increased BMI increases the incidence of pulmonary aspiration in a linerar fashion
false- no solid evidence that BMI alone increases risk of aspriation
RSI can be considered if other factors such as GERD or DM are present (gastroporesis)
When is postop hypoxemia most likely to occur in the obese patient?
immediately postop and upt o 2-5 days following surgery
5 ways to maximize postop oxygenation in the obese patient
- hob up 30 degrees
- cpap or bipap
- IS
- early ambulation
- pain control with non-opioid analgesics/regional
Considerations for the CV effects of the morbidly obese patient: select 2:
-increased baseline HR
-increased EKG voltage
-diastolic dysfunction
-increased venous return
diastolic dysfunction and increased venous return
- increased intravascular volume = increased wall stress
- –> heart compensates by becoming thicker; thicker = unable to relax
-HR is usually unchanged bc an increased SV is responsible for the increased CO
How much does cardiac output increase for every extra kg of fat?
100mls/min
T/F- increased HR in obese population is expected
false- usually no change - increased SV accounts for increased CO
Why would an obese patients heart be dilated?
Venous return must match cardiac output, so the heart dilates to accept the larger incoming volume.
then also becomes thicker to compensate for increased wall stress
-> reduces ventricular compliance and causes diastolic dysfunction
*makes them less tolerant of excessive fluids, putting them at risk for fluid overload (pulm edema)
*use LBW to calculate periop fluid requirements
Concerns with fluid managment if you dont have an echo to tell you their heart function- what can you assume
well they have this increased circulating intravascular volume in order to perfuse all this extra fat:
-venous return must match CO, so the heart will dilate to accept more volume
-this increased volume makes the heart work harder and overtime it becomes stiffer to compensate at the expense of it being able to relax (diastolic dysfunction)
-so they dont handle excessive fluid administration very well - at risk for fluid overload nad pulm edema
calculate fluid requirements based on LBW
What are some common EKG changes in the obese patient (6) and why
- Low voltage EKG - caused by increased distance between the heart and leads
- Left axis devation - stomach pushes heart up and to the left + LVH secondary to volume overload and HTN
- Right axis devation - from RVH due to OSA and volume overload
- Ischemia - supply and demand mismatch
- Dysrhythmias - fatty infiltration of hte conduction system, myocardial hypertrophy, hypoxemia, hypercarbia, obesity hypoventilation syndrome, and ischemic heart diease
The presence of what on TEE may be the most useful confirmation of pulmonary HTN?
tricuspid regurgitation
In the obese patient, which factors are expected to increase (select 2):
-MAC
-Circulation time
-Volume of distribution of lipohhilic drugs
-Volume of distribution of hydrophilic drugs
Volume of distibution of both lipophilic and hydrophilic drugs
- the Vd of lipophilic drugs is higher due to a larger fat mass
- the Vd of hydrophilic drugs is increased due to a larger muscle mass and blood volume
A high CO hastens (speeds) IV drug delivery to the site of action, shortening circ time (go to sleep quicker with IV induction)
MAC is unchanged
How does obesity affect lipophilic vs hydrophilic drugs
- the Vd of lipophilic drugs is higher due to a larger fat mass
- the Vd of hydrophilic drugs is increased due to a larger muscle mass and blood volume
As a rule of thumb, what kind of drugs are calculated with what kind of weights?
TBW- lipid-soluble drugs
IBW- water-soluble drugs
obesity increases volume of distribution of both water and lipid soluble drugs, so LBW can be used to account for this
T/F: a loading dose is primarily depdendent on the volume of distribution, while the maintenance dose is determined by clearance
true
what happens when you give a lipophilic drug to the obese population?
bc the drug will just distribute into the fat compartments, lowering the plasma concentration
Using IBW may result in (overdose/underdose) of a drug in the obese population
What about TBW
underdose bc the Vd is larger in the obese population (higher blood volume, higher muscle mass)
may overdose bc fat is less fascular than other tissue , so a greate % of the loading dose will go to the vessel-rich group
Why don’t you want to dose lipophlic drugs on TBW in the obese population?
bc fat receieves a smaller amount of the CO, so a greater % of the loading dose will go to the VRG
Calculation for LBW
IBW x 1.3
How is defluorination affected by obesity and iso/sevo/des
iso and des - increased defluorination (but not linked to postop hepatic or renal dysfunction)
-no change in sevo
When giving a choice of: sevo, des, iso, and propofol - which 2 agents provide the FASTEST emergergence?
sevo and des
When giving a choice of: sevo, des, iso, and propofol - which 2 agents provide the FASTEST emergergence?
sevo and des
Engorgement of hte epidural veins and increased epidural fat will cause a greater spread of local anesthetic in the epidural space. For this reason, the dose should be reduce to what % of the normal dose?
75%
Which drugs are soley based on TBW vs LBW regardless of induction vs maintenance dose
-PROPOFOL
-MIDAZ
-FENT/SUFENT
-REMI
-ROC/VEC
-CIST/ATRA
-SUX
All TBW = MIDAZ - SUX - CIST/ATRA
All LBW = REMI - ROC/VEC
Variable: Propofol & Fent/Sufent
& they are opposite
Prop induction = LBW, mainteneance = TBW
Fentanyl induction = TBW, maintenance = LBW
Why do we use TBW to calculate Sux if it’s water soluble
water soluble drugs are typically IBW
- increased blood volume (increased Vd) and
- increased pseudocholinesterase activity (increased clearance)
T.F - obesity results in decreased pseudocholinesterase activity
False - increased
*increased clearence of sux - larger dose needed
What is remi always based on and why?
LBW
-it’s rapidly cleared by plasma esterases, so it behaves more like a water-soluble drug
i guess IBW in regular people but shifts to LWB in obese bc LBW helps account for the increased muscle mass…
T/F: how is the absorption of orally administered meds affected in the obese population
no difference
All of the following muscles dilate the upper airway EXCEPT the:
-tensor palantine
-genioglossus
-hyoid muscles
-thyroaretenoid
-thyroarytenoid
What muscle opens the nasopharynx ?
tensor palantine
What muscle opens the oropharynx?
Genioglossus (tongue)
What muscles open the hypopharynx?
The hyoid muscles
T/F: the incidence of OSA is directly proportional to BMI
True
T/F: OSA is an indepdent risk factor for the development of HTN, CV morbidity, and death
True
OSA is definted as cessatation in airflow for at least how long (apnea)….with how many unsuccessful efforts to breathe (obstruction) and a greater than what % reduction in SaO2
10 second apneic period
5 or more unsuccessful efforts to breathe
> 4 % reduction in SpO2
What is definited as a 50% reduction in airflow for 10 seconds, 15 or more times per hour and is linked to snoring and decreased o2 sats
hypopnea
Neck girth risk in men vs women for OSA
men- neck > 17inches
women- neck >16
Describe the pathophysiologic cycle of apnea:
sleep → decreased upper airway tone → increased upper airway resistance → obstruction (snoring) → hypoemia/hypercarbia (SNS stimulation) → arousal (daytime sleepiness) → increased upper airway tone → pt breathes
Which apnea/hypopnea index score is consistent with mild OSA?
-3
-12
-25
-40
12
The value is derived by the number of apnea episodees and hypopnea divided by the total hours of sleep
Mild = 5-15 epidodes/hr
moderate = 15-30 episodes/hr
severe > 30 episodes per hour
Why is it important to screen all patients for OSA?
bc most patients are underdiagnosied and it’s a major contributer to periop M&M
What is the definitive test for OSA?
Polysomnography
How many episodes per hour determines miild, moderate, vs severe sleep apnea
what is the rating system called?
5-15 = mild
15-30 = moderate
>30 = severe
Apnea-hypopnea index (AHI)
Bedside assessment tool for OSA
how many = high risk vs low risk
STOPBANG
Snoring
Tirdness
Observed apnea
Pressure*
BMI >35 (obese class 2) *
Age > 50 *
Neck circumfrence > 40cm
Gender - male *
* = things you can get from chart
=/> 3 yeses = high risk
<3 = low risk
so a male over 50 with HTN = high risk just with those 3 yeses alone
How many patients with sleep apnea are undiagnosed?
60-70%
T/F: Obesity hypoventilation syndrome is a long-term consequence of untreated OSA
True
overtime, the respiratory center in the medulla fails to respond to hypercarbia appropriately
3 diagnositic critera for obesity hypoventilation syndrome
- BMI > 30 (obesity class 1 compared to class 2 [>35] for OSA)
- Awake PaCO2 > 45
- Dysfunctional breathing during sleep
Risk of anesthesia and Pickwickian syndrome
administation of any respiratory depressant drugs puts these patients at high risk of airway obstruction nad resp arrest
*when planning your management, try to think of multi-modal approaches to pain that do not impact resp drive: regional, nsaids, tylenol, ketamine, dex
What is the MOST sensitive sign of an anastomotic leak following gastric bypass?
A. shoulder pain
B. unexplained tachycardia
C. abdominal pain
D. fever
B. unexplained tachycardia
T/F- bariatric surgery is the most effective treatment f or reversing obesity
True
T/F: bariatric surgery usually leads to resolution of comorbidities such as HTN and type 2 diabetes
True
What are the 3 approaches to surgical weight loss
which yeilds the best weight loss and improvement of comorbidities?
- malabsorption (jejuno-ileal bypass)
- restriction (gastric band and sleeve gastrectomy)
- combination (roux-en-y- gastric bypass)
roux-en-y
T/F- duodenal switch is the least invasive bariatric procedure
False- gastric bands/sleeves are least invasive (restrictive surgeries)
duodenal switch is a malabsorptive
What type of bariatric procedure: malabsoprtive, restrictive, combination:
Jejunoileal bypass
Malabsorption
-gastric reduction and removal of part of the small intestines, limitng nutrient absorption
What type of bariatric procedure: malabsoprtive, restrictive, combination:
gastric band
restrictive
-limits quantitiy of food that can be consumed
*restrictive procedures are least invasive
What type of bariatric procedure: malabsoprtive, restrictive, combination:
Bilopancreatic diversion
Malabsorption
gastric reduction and removal of portion of hte small intestine
-limits nutrient absorption
What type of bariatric procedure: malabsoprtive, restrictive, combination:
Roux-en-Y gastric bypass
combination
bands/sleeves
yields best weight loss and improvement
*risk of nutritional deficiency
What type of bariatric procedure: malabsoprtive, restrictive, combination:
does NOT lead to nutrient deficiency
Restrictive
small intestine is left intact!
What type of bariatric procedure: malabsoprtive, restrictive, combination:
Sleeve gastrectomy
Restrictive
-least invasive, no nutrient issues
-limits amount of food that can be consumed
What type of bariatric procedure: malabsoprtive, restrictive, combination:
duodenal switch
malabsorption
gastric reduction and removal of part of the small intestine
if someone has a gastric band or sleeve- are you consered about nutrient deficiencies?
no- small intestine is left intact
this is the least invasive type of procedure
small intestine is left intact
If someone has a history of a duodenal switch, jejunoileal bypass, or bilopancreatic diversion, or roux-en-y gastric bypass- what do you want to look at ?
why might you want to avoid nitrous
Coags - poss increased INR due to vitamin K deficiency
risk of having vit b12 deficinecy and folate depletion
Gastric bypass is associated with what % of an anastomotic leak:
0.02%
0.2%
2%
12%
2%
What do you know about toradol and gastric bypass surgery
old evidence says its contraindicated due to risk of bleeding and ulcers but the latest evidence suports it as a means to reduce opioid consumption
3 most common s/s anastomatic leak
- tachycardia (72%)
- fever (63%)
- abdominal pain (54%_
unexplained tachycardia is most sensitive sign.
unexplained HR of > 120bmp is concerning even if no other s/s present
Match each appetite suppressant with it’s drug class:
-Phentermine
-Ma Huang
-Sibutramine
-Orlistat
- Ephedra alkaloid, NE reuptake inhibitor, NE and serotonin reuptake inhibitor, lipase inhibitor
-Phentermine: NE reuptake inhibitor
-Ma Huang + Ephedra lkaloid
-Sibutramine + NE and SSRI
-Orlistat + Lipase inhibitor
T/F: Obesity is the most significant risk factor for hte development of nonalcoholic fatty liver disease (NAFLD) and nonalcholic steatohepatitis (NASH)
True
How should you calculate fluids for obese ppls
LBW
many obese pts have diastolic dysrunction which means they are less tolerant of excessive fluid administration, placing them at risk for fluid overload
OSA is associated with cessitation of airflow for more than:
A. 10 seconds
B. 15 seconds
C. 20 seconds
D. 25 seconds
A. 10 seconds
Which of the following are associated with obesity? (select 3)
-increased total body water
-decreased lean body weight
-decreased Vd of lipid soluble drugs
-increased blood volume
-increased CO
-increased renal clearance
increased blood volume
-increased CO
-increased renal clearance
All of the following contribute to HTN in the obese ptatient EXCEPT:
A. Cytokines
B. Hyperinsulinemia
C. angiotensinogen
D. decreased blood viscosity
D. decreased blood viscosity
*they have increased blood viscostiy
Blood pressure can increase how much for every 10% increase of body weight?
6.5mmHg
seems like a random triva question
Which of the following complications are associated with maternal obesity (select 2):
-decreasedd duration of 1st stage labor
-increased risk of preterm labor
-excessive blood loss during c-section
-increased risk of type 1 diabetes
-increased risk of preterm labor
-excessive blood loss during c-section
- increased duration of first and second stages of labor
- increased risk of needing a c-s
- increased risk of surgical complications
- increased incidence of macrosomnia (large for gestational age)
T/F- maternal obesity increases the risk of needing a C/S
True
What is the estimated blood volume of the patient with class III obesity?
A. 40ml/kg
B. 50ml/kg
C. 60ml/kg
D. 70ml/kg
B. 50ml/kg
