Exam 3: Obesity Flashcards
What is the #1 cause of medically-related preventable deaths?
Smoking
Obesity is #2.
S2
Calculation for BMI
Kg/m^2
S3
Shortcommings of the BMI calculation
- Doesn’t differentiate between overweight and overfat
- Doesn’t account for waist circumference, waist-hip ratio or age
S3
What is the android body fat distribution, and what is it associated with?
- “central” or truncal obsity
- ↑ O₂ consumption
- CV disease
S4
Gynecoid body fat distributions are described as ____ obstity around the ____. This shape is ____ metabolically active and not as associated with ____ disease.
Gynecoid body fat distributions are described as peripheral obestity around the hips, butt and thighs. This shape is less metabolically active and not as associated with CV disease.
S4
Total blood volume is ____ in obesity.
increased
because of increased mass
S5
Obesity blood volume to weight ratio is typically lower than ____ mL/kg.
50 mL/kg
most volume gets distributed to adipose tissue
S5
What occurs with cardiac output in obese patients?
CO will ↑ by 20-30 mL per kg of excess body fat.
CO increases due to LV dilation and ↑ stroke volume.
S5
What causes an increase in cardiac dysrhythmias in the obese patient?
- Fatty infiltrates in the conduction system
- CAD
S5
What EKG changes are typical of the obese patient?
- ↓ QRS voltage
- LV hypertrophy
- Left axis deviation
S5
Increased levels of what coagulative factors are noted in obesity?
- Fibrinogen
- Factor VII
- Factor VIII
- Von Willebrand
Increased levels = hypercoagulability.
S6
Why does endothelial dysfunction occur in the obese patient?
Due to ↑ factor VIII and von Willebrand.
S6
Gastric ____ and ____ are increased in the obese patient.
Gastric volume and acidity are increased.
S7
What intubation risk factors are present in an Obese patient due to changes in the GI system?
- Delayed gastric emptying
- ↑ chance of gastric volume > 25mL
- ↑ chance of pH < 2.5
The low pH and increased gastric volume increase chance for aspiration pneumonitis
S7
Hepatic function is altered = drug metabolism altered
What are the results of increased intragastric pressure secondary to obesity?
- LES relaxation
- Hiatal hernia formation (often asymptomatic)
S7
Glomerular ____ occurs with obesity due to increased renal blood flow.
hyperfiltration
S8
What are the consequences of increased renal tubular reabsorption secondary to obesity?
- Impaired natriuresis
- RAAS activation = therefore increased systemic BP
S8
What are the endocrine effects of obesity?
- ↑ SNS activity
- Insulin resistance/impaired glucose metabolism
- Enhanced NE and Angiotensin II activity
- Na⁺ retention (coupled with poor diet contributes to HTN)
- Thyroid hormone resistance = hypothyroidism in 25% of morbidly obese pts
INSET
S9
Common diseases seen in association with obesity
- Type 2 diabetes mellitus
- Obstructive sleep apnea (side effect of the underlying process)
- Asthma
- Chronic obstructive pulmonary disease
- Hypertension
- Cardiovascular disease
- Cancer
- Osteoarthritis (increased wear/tear on the body bc of increased weight)
D10
Metabolic syndrome diagnosis requires 3 of the following:
- Abdominal obesity
- ↓ HDL levels
- ↑ Triglycerides
- Hyperinsulinemia
- Glucose intolerance
- Hypertension
- Inflammatory state
- Thrombotic state
S11
Risk factors for metabolic syndrome
- Increased age
- Men
- Hispanics and South Asians
HIM
S12
What drugs may cause metabolic syndrome?
- Chronic corticosteroids
- Antidepressants
- Antipsychotics
- Protease inhibitors
S12
With metabolic syndrome, pts have an increased risk of
- CV disease
- DM2
- PCOS
- Non-ETOH fatty liver disease
- Improper immune responses
98% resolved with bariatric surgery and achieving weight loss goal
S13
Differentiate OSA and hypopnea.
- OSA: Complete cessation of breathing lasting 10 seconds or more (5 times or more an hour) decreased sat by 4%
- Hypopnea: Airflow reduction by ≥ 50% lasting 10 seconds or more (15 times or more an hour) decreased sat by 4%
S14
What is a sleep study called
polysomnography
S15
What would a mild apnea/hypopnea index be?
5 - 15 events/hour
S15
What would a moderate apnea/hypopnea index be?
15 - 30 events/hour
S15
What would a severe apnea/hypopnea index be?
More than 30 events/hour
S15
CPAP is necessary for treatment of moderate or severe OSAHS (Obstructive sleep apnea and hypopnea syndrome) due to risk of what complications?
- Systemic/Pulmonary HTN
- LVH
- Dysrhythmias
- Cognitive impairment
Saul Left Dracula Carefully
S15
What’s another name for Obesity Hypoventilation Syndrome?
Pickwickian Syndrome
S16
What causes Pickwickian syndrome?
Long-term OSA
5-10% of mobidly obese
S16
What does Pickwickian syndrome cause?
Pulm HTN and Cor Pulmonale
S16
How is Pickwickian syndrome diagnosed?
- > 30 BMI
- Awake hypercapnia
S16
What drug(s) classes are used to treat obesity?
- Phentermine
- Orlistat
- OTC Herbals
- GLP-1 Agonists
S17
How does Phentermine work?
What are it’s side effects?
- Sympathomimetic that decreases appetite
- ↑HR, palpitations, HTN, dependence, abuse
S17
How does Orlistat work?
What are the adverse effects associated with it?
- Orlistat blocks absorption of dietary fat
- do I remember with Dr. T that orlistat is a 5HT3 inhibitor?
- Lipase inhibitor, not 5HT3 inhibitor
- oh sibutramine is the 5HT3/NE inhibitor…
- Liquid, fatty stools, urgency, flatulence, cramping and malnourishment.
- Fat soluble vitamin deficiencies
S17
How can Orlistat precipitate coagulopathy?
Possible Vit K deficiency → prolonged PT
S17
Which herbals are pancreatic lipase inhibitors?
Caffeine
Green Tea
S17
How do ginseng, ephedra, and sunflower oil “treat” obesity?
Appetite suppression
S17
What berry is an OTC herbal energy stimulant?
Acai
S17
What OTC Herbals regulate lipid metabolism?
- Soybean Oil
- Fish Oil
- Oolong tea
S17
For patients taking a GLP-1 Agonist on a weekly basis, it is recommended to hold the dose for ____ prior to surgery.
1 week
S18
How would a patient be treated if they forgot to hold their GLP-1 Agonist prior to surgery?
The patient is to be treated as a full stomach or gastric contents need to be evaluated by US.
S19
What to focus on with an obese pt in your preop eval
- HTN
- DM
- HF
- Hypoventilation syndrome or OSA
S24
CPAP pressures usage of > ____ cmH₂O are associated with difficult mask ventilation.
10 cmH₂O
Corn says to make them very awake for induction and emergence
S24
Preop eval surgical history things to focus on
FYI slide
- compare past vs current weight
- ease vs difficult intubations based on past notes
- IV access
- do they need an ICU admission?
- what were the surgical outcomes?
Even if they have lost weight, they may still have some comorbidities associated with obesity - these pts tend to do poorly with sx (bad wound healing etc)
S25
Considerations for obese pts going to the OR
FYI slide
- continue home meds (except antihypertensives, insulin and oral hypoglycemics)
- ABX
- DVT prophylaxis
- Aspiration prophylaxis (pepcid or more)
S26
Ventilation abnormalities we should expect in an obese pt
- decreased VC
- decreased IC
- decreased ERV
- decreased FRV
- low compliance
S27
How does closing capacity compare to tidal breathing in the morbidly obese patient?
Closing capacity ≈ Tidal breathing
Especially when recumbent/supine - we will see rapid desatting.
S27
Plan for these things with your intraoperative care of an obese pt
(FYI and duh)
- Positioning (can be difficult)
- Airway management (plan for the worst - glidescope)
- Monitoring
- Choice of anesthetic technique
- Pain control
- Fluid management
S29
What is the most important respiratory/ventilatory intervention that can be done for the obese patient prior to intubation?
Preoxygenate.
Corn
Complications of the supine position with an obese pt
- Ventilatory impairment
- Compression of IVC and Aorta
- Rhabdomyolysis of the gluteal muscles - leads to renal failure and death
S30
Is prone or lateral decubitus positioning preferred in the obese patient?
Lateral decubitus
S30
What oropharynx change occurs with obesity?
Oropharynx shape becomes elliptical w/ a short transverse and long AP axis.
S35
Increased ____ ____ deposited into the airways can complicate airway management.
Adipose tissue
S35
What is the relationship between degree of obesity and pharyngeal area?
Inverse relationship
More obese = Less pharyngeal area.
S35
What predictors of difficult intubation are of particular importance in the obese patient?
- BMI (though not all the time)
- Small mouth opening
- Large Teeth
- Limited neck mobility
- Retrognathia or micrognathia
S36
What axes need to line up for intubation?
Laryngeal, Pharyngeal, and oropharyngeal
with obese pts, don’t just lift up the head, their shoulders need lifting up too and neck extension
S37
How quickly will a patient with a normal BMI desaturate from 100% to 90% SpO₂?
6 minutes
Andy
How quickly will a patient with a morbidly obese BMI desaturate from 100% to 90% SpO₂?
3 minutes or less
Andy
What is the best positioning on an OR table for recruitment in an obese patient?
- 30° Reverse Trendelenburg
- 25-30° with the head up
S41
What measures should be taken for alveolar recruitment to prevent atelectasis and desaturation in the obese patient?
- CPAP 10 cmH₂O during preoxygenation
- Positioning
- Recruiting maneuvers then PEEP 10cm
- Mechnical ventilation after induction
S41
Which drug classes have exaggerated responses in obese patients (particularly those with OSA) ?
- Opioids
- Benzo’s
- Propofol
S45
Which agents are preferred in obese OSA patients?
Short-acting Opioids
- Remifentanil
- Fentanyl
- and α2 agonists…dexmedetomidine
S45
What dose of propofol would you use for induction in an obese pt?
Trick Question: Volatiles are preferred over prop because you have more control - but these pts do hang onto volatiles longer desflurane is targeted for these pts
S45
____ is not a favored volatile in obese patients due to their greater O₂ demand.
N₂O
but Corn likes it because it’s off faster
S45
What drug class (in general) will diminish ventilatory response to CO₂?
Volatile anesthetics
S45
Initial dosing of drugs in obese patients should be based on ____
Lipid solubility of the drug
S46
Which common anesthetic drugs are dosed based on Ideal Body Weight (IBW)?
- Propofol
- Vecuronium
- Rocuronium
- Remifentanil
I PRRV (this is slide 69…Perv)
S46
Ideal Body weight Calculation
I have a feeling they may be tricky and ask this….
Men IBW = 50kg + 2.3 kg for each inch over 5 feet
Women IBW = 45.5 + 2.3 kg for each inch over 5 feet
Dr. T
Which common anesthetic drugs are dosed based on Total Body Weight (IBW)?
- Midazolam
- Succinylcholine
- Cisatracurium
- Fentanyl
- Sufentanil
MS Combs Found Sue
S46
Why do obese pts get cold quicker?
Larger surface area
be aware of your thermal management
S47
IV fluids requirements are ____ than what’s predicted in order to prevent acute tubular necrosis in the obese patient.
greater
S48
