Obesity-Dr.Brown PP Flashcards
1
Q
What is the current estimated percent of US adults classified as overweight or obese?
A
75% or over 210 million
2
Q
Or more men or women currently classified as overweight or obese in the US?
A
Women at 40.4%
3
Q
In obese patients, the highest risk of death is do to?
A
Cardiovascular causes
4
Q
What states have the highest obesity rates?
A
West Virginia, Mississippi, Alabama, Louisiana, Alaska
5
Q
What states have the lowest obesity rates?
A
Hawaii, Massachusetts, Washington DC, Colorado
6
Q
BMI is the accepted measure of body habit that describes?
A
Adiposity normalized for height
7
Q
What are the two formulas for BMI?
A
BMI= Weight(kg)/Height(m^2)
BMI= (Weight(lbs)/Height(in.^2)) x 703
8
Q
Overweight is defined as a BMI of?
A
25-29 kg/m^2
9
Q
Obesity is a BMI of?
A
30kg/m^2
10
Q
The term morbid obesity has been abandoned and replaced with?
A
Extreme obesity
11
Q
Extreme obesity is a BMI of?
A
40kg/m^2 or more
12
Q
Ideal body weight (IBW) is used interchangeably with what terms?
A
Normal weight and desirable weight
13
Q
Body weight that is 20% in excess of the ideal body weight at a height constitutes?
A
Obesity
14
Q
A body weight that is twice the ideal body weight is deemed?
A
Extreme obesity
15
Q
What are the calculations for men and women for ideal body weight?
A
Men: IBW= Height(cm) - 100
Women: IBW = Height(cm) - 105
or
Men: IBW = 105lb + 6lb for each inch >5ft
Women: IBW = 100lb + 5lb for each inch >5ft
16
Q
What are the two major disadvantages of using ideal body weight?
A
- Indicates that all patients of the same height receive the same dose.
- Does not account for changes in body composition associated with obesity, specifically calculated IBW of an extreme obesity patient is less than their actual lean bodyweight.
Therefore, administration of a drug based on IBW may result in underdosing.
17
Q
How much does lean body mass increase by in obese individuals due to the increased muscle developed to carry extra body weight?
A
30%
18
Q
What percent higher is lean body weight than ideal body weight?
A
30%
19
Q
What is the calculation for lean bodyweight (LBW)?
A
LBW = IBW X 1.3
20
Q
What body weight is the most appropriate dose for most anesthetic drugs? What is the exception?
A
Lean bodyweight
With the exception of nondepolarizing neuromuscular blockers where ideal body weight may be more appropriate
21
Q
For Succinylcholine, what body weight should you use to dose?
A
Total body weight
22
Q
What body weight should be used for Midazolam administration? Why? What side effects might you see?
A
-Total body weight
-Because of an increase central volume of distribution. Dosing this way will prolong the elimination half-life, and it duration of effect.
-may cause over sedation and obese patients who are sensitive to respiratory depressant drugs
23
Q
What body weight should Initial doses of Fentanyl and Sufentanil be administered? Why? What about Maintenance dosing?
A
Initial doses should be based on total body weight because of their fat solubility in large volume of distribution (prolonged elimination half-life)
Maintenance dosing is based on lean body weight
24
Q
What drug, even though water-soluble, is dosed for intubation using total body weight? Why?
A
Succinylcholine
Due to the combination of an increased blood volume (increased Vd) and increased pseudocholinesterase activity (increased clearance) necessitates a total bodyweight dose be given to ensure adequate paralysis.
This is the clear exception to the rule for water, soluble drugs!!!
25
Dosing of Propofol for Induction and Maintenance should be based off of which body weights for obese patients?
Induction Dose: Lean Body Weight
Maintenance Dose: Total Body Weight
26
Dosing of Rocuronium, Vecuronium, and Cisatracurium should be based off of which body weights for obese patients?
Ideal Body Weight
27
Dosing of Remifentanil should be based off of which body weights for obese patients?
Ideal Body Weight
28
Dosing guidelines for Precedex in obese patients?
Infusion Rates of 0.2mcg/kg/min
29
Dosing guidelines for Sugammadex in obese patients?
Total Body Weight
30
How is total body water changed in obese patients?
Reduced total body water
31
How is cardiac output and blood volume changed in obesity?
Increased cardiac output and increased blood volume
32
How is renal clearance changed in obesity?
Increased renal clearance
33
How does the volume of distribution of lipid soluble drugs change in obesity?
Increased volume distribution
34
Is liver function, usually normal or abnormal in obesity
Abnormal (per Dr. brown slides)
35
As a general rule of thumb, water-soluble drugs in the obese patient are dosed according to what body weight.?
Ideal body weight
(Succ is the exception)
36
As a general rule of thumb, lipid-soluble drugs in the obese patient are dosed according to what body weight.?
Total body weight
37
What inhalation agents are good for the obese patient?
Desflurane, Sevoflurane, and Nitrous Oxide
38
What are some cardiovascular conditions associated with obesity?
Coronary heart disease
Hypertension
Dyslipidemia
Cerebrovascular disease
Thromboembolic disease
Cardiomegaly
Congestive heart failure
Pulmonary hypertension
39
What are some endocrine related conditions associated with obesity?
Type two diabetes
Thyroid disorders
40
What are some respiratory related conditions associated with obesity?
Restrictive lung disease
Obesity hypoventilation syndrome
Obstructive sleep apnea
41
What are some gastrointestinal conditions associated with obesity?
Hiatal or inguinal hernia
Gallbladder disease
Non-alcoholic fatty liver disease: steatosis, cirrhosis, hepatomegaly
Gastroesophageal reflux disease (GERD)
42
What are some other miscellaneous conditions associated with obesity?
Gout
Infertility
Impaired immune response
Wound infections
Osteoarthritis
Malignancy: esophageal, gallbladder,:, breast, uterine, cervical, prostate, renal
Urinary incontinence
Pancreatitis
Low back pain
Obstetric complications
43
Which obesity shape is less correlated with significant disease?
Peripheral gynecoid or gluteal femoral obesity
Pear shape
44
Peripheral gynecoid or gluteal femoral obesity has a waist/hip ratio below?
0.76
45
Central, android, or abdominal visceral obesity has an increased risk of?
Heart, disease, hypertension, diabetes
46
Gynecoid, body shape characteristics
Fat mainly located in the upper legs
Has a better prognosis, but difficult to treat
47
Health risks associated with the gynecoid body shape
Osteoporosis
Varicose veins
Cellulite
Subcutaneous, fat traps and stores dietary fat
Trapped fatty acids stored as triglycerides
48
Android body shape characteristics
Fat primarily located in the abdominal area
Fat also distributed over upper body such as neck, arms, shoulders
Greater risk for obesity related complications
49
Health risks associated with android body shape, fat distribution
Heart disease
Diabetes
Breast cancer
And endometrial cancer
Visceral fat is more active, causing
-decreased insulin sensitivity
-Increased triglycerides
-Decreased HDL cholesterol
-Increased blood pressure
-Increased free fatty acid release into blood
50
What waist circumference in men and women increase the risk of ischemic, heart disease, diabetes, hypertension, dyslipidemia, and death?
Men: waist circumference greater than 102 cm (40 inches)
Women: waist circumference greater than 88 cm (35in)
51
What is the primary factor (%) of genetic predisposition to obesity?
40% Genetic
the other 60% come from other variables such as age, sex, race, lifestyle, economic status
52
The American heart Association in the national heart-lung and blood institute to find metabolic syndrome as the presence of three or more of the following criteria:
1. Elevated was circumference.
2. Elevated triglycerides. (>150mg/dL)
3. Reduced HDL cholesterol.
Men<40
Women<50
4. Elevated blood pressure.
130/85
5. Elevated fasting glucose.
>100mg/dL
53
For every 13.5kg (29.48lb) of fat gained, an estimated 25miles of neovascularization occurs to provide blood flow at a rate of 2-3mL/100g of tissue/min. This represents an increased CO of ________ of fat acquired.
0.1L/min per kilogram of fat acquired
(100mL/min per kilogram of fat)
54
How do the demands put on the heart from obesity impact cardiac output, oxygen consumption, and carbon dioxide production?
All are increased!
55
On TEE, what may be the most useful confirmation of pulmonary hypertension?
Tricuspid regurgitation
56
The prevalence of hypertension in obese patients is usually how much more than those and lean men and women?
2x more
57
How many mmHg does blood pressure increase for every 10% increase in body weight?
6.5mmHg!
58
The development of hypertension in obese patients is often precipitated by:
-increase blood viscosity d/t catecholamine kinetics, and possibly increased estrogen concentrations
-hyperinsulinemia, elevated mineralocorticoids, and abnormal sodium reabsorption
-arrhythmias
59
Arrhythmias and the obese patient may occur as a result of:
Hypoxemia
Hypercapnia
Electrolyte disorders
Sleep apnea
Ventricular hypertrophy
Hypertension
Coronary artery disease
60
What spinal column changes can develop in the obese patient resulting in impaired movement and fixation of the thorax in an inspiratory position
Thoracic kyphosis
Lumbar lordosis
61
what respiratory body mechanics can be reduced up to 35% of predicted values in obese patients?
Chest wall compliance
Lung/Parenchyma Compliance
Pulmonary Compliance (chest wall + lung)
62
Why do obese patients have an increased myocardial oxygen consumption?
Metabolic needs of the fat organ and greater mechanical work of breathing
63
Respiratory muscle efficiency is reduced in obese patients which can be seen by?
Reduced FRC
Premature airway closure
Increased dead space
CO2 retention
V/Q mismatch
Shunting
Hypoxemia
64
Which lung volumes are reduced in obese patients?
Functional residual capacity
Expiratory reserve volume
Total lung capacity
65
What is Functional Residual Capacity?
What is normal functional residual capacity? What to volumes make up FRC?
The volume of air remaining in the lung at and expiration. Provides a reservoir of gas to alveoli during apnea.
35mL/kg (~2,300mL)
Residual volume + Expiratory reserve volume
66
What is normal Total Lung Capacity?
What volumes make up TLC?
~5,800mL (5.8L)
Inspiratory reserve volume + tidal volume + expiratory reserve volume + residual volume
67
What is expiratory reserve volume?
What is normal?
Volume of gas that can be forcibly exhaled after a tidal exhalation.
Normal: ~1,100mL (1.1L)
68
What is closing capacity? what two volumes make up closing capacity?
The absolute volume of gas contain in the lungs when the small airways close.
Residual volume + closing volume
69
In obese patients, lung inflation is inhibited, which causes a decline in FRC to less than ________?
Closing capacity
70
Recurrent hypoxemia leads to?
Secondary polycythemia and is associated with an increased risk of coronary artery disease and cerebrovascular disease.
71
Is obesity create a more of a restrictive or obstructive lung disease?
Restrictive lung disease
72
Obesity hypoventilation syndrome is presumptively diagnosed with a:
Sp02 < 94% and a PaC02 > 45 mm Hg in obese patients.
73
Which is the most accurate statement regarding the airway evaluation of an obese patient?
A. BMI is a definitive risk factor for intubation
B. increased neck, circumference and a Mallampati class 3 our strong predictors of difficult tracheal intubation
c. Obstructive sleep apnea is a dependent risk factor for difficult mask ventilation
d. Risk factors for difficult mask, ventilation in difficult intubation overlap.
B. increased neck, circumference and a Mallampati class 3 our strong predictors of difficult tracheal intubation
74
When mechanical ventilation is initiated in an obese patient, how does oxygen consumption change?
Reduced oxygen consumption, ~15%, that is not seen in normal weight patients
75
What percent of all surgical patients are at high risk for OSA?
25% due to the under diagnosed prevalence of OSA
76
OSA is characterized by?
Excessive acne episodes (10 seconds) and hypopnea during sleep that are causes be complete or partial upper airway obstruction which leads to episodes of apnea-hypopnea arousal and oxygen desaturation.
77
What is the most common comorbidity of OSA?
Hypertension
78
What is apnea? When is it considered obstructive?
the cessation of airflow at the nose and mouth for more than 10 seconds.
Apnea is considered obstructive if there is continued respiratory effort despite airflow
cessation.
79
What is the definition of hypopnea?
defined as a 50% reduction in airflow for 10 seconds for 15 or more times per hour of sleep associated with snoring and a 4% decrease in oxygen saturation.
-a transient reduction in airflow caused by increased upper
airway resistance
80
What is the gold standard for OSA diagnosis?
Overnight polysomnography
81
OSA is diagnosed by?
The presence of at least five obstructive apneas, hypopneas, or both per HOUR while patient is sleeping
82
What is the apnea-hypopnea index?
The number of abnormal respiratory events per hour of sleep
83
what is the minimal clinical diagnosis for OSA?
AHI of 10 plus symptoms of excessive daytime sleepiness
84
What are the mutilated, moderate and severe AHI scores?
Mild OSA: AHI 5–15
Moderate OSA: AHI 15–30
Severe OSA: AHI> 30
85
What does Medicare recognize as OSA?
AHI of 15 or AHI of 5 with two comorbidities
86
What is STOP-BANG?
87
What are some factors to consider in determining if an obese patient is appropriate for outpatient surgery care?
1) Sleep Apnea status
2) Anatomical and physiologic abnormalities
3) Status of coexisting diseases
4) Nature of surgery
5) Type of anesthesia
6) Need for postop opioids
7) Patient age
8) Adequacy of post discharge observation
9) Capabilities of the outpatient facility
*OSA patients with controlled comorbidities may be reasonable candidates for ambulatory surgery if their pain can be appropriately managed with minimal or no postoperative opioids
88
Pickwickian syndrome is also known as?
Obesity hypoventilation syndrome
89
What percent of patients with extreme obesity have obesity hypoventilation syndrome? what are characteristics of OHS?
8% of obese pop.
1. OSA
2. Hypercapnia (CO2 retention)
3. Daytime Hypersomnolence (can be inappropriate and sudden)
4. Arterial Hypoxemia
5. Cyanosis-induced Polycythemia
6. Respiratory Acidosis
7. Pulmonary HTN
8. Right sided heart failure
9. Extreme: nocturnal episodes of central apnea, apnea without respiratory efforts, reflecting
progressive desensitization of the respiratory centers to nocturnal hypercarbia
90
Obese patients have an increased incidence of what G.I. diseases?
GERD
Gallstones
Pancreatitis
Liver abnormalities: non-alcoholic fatty liver disease
91
Signs and symptoms of non-alcoholic fatty liver disease
steatosis (fatty liver), steatohepatitis, fibrosis, cirrhosis, hepatomegaly, and abnormal liver biochemistry (asymptomatic)
92
Pathogenesis of non-alcoholic fatty liver disease
➢ Insulin resistance, diabetes, ↑triglycerides
➢ Central obesity
➢ ↑ risk of developing CV disease and diabetes
93
How does the classification for obesity differ from that of pediatric obesity?
* Obesity is > than the 90th percentile or a BMI greater than or equal to the 95th percentile, age and sex specific.
* Pediatric obesity: BMI greater than the 95th percentile on the (CDC) growth chart
94
Obese adolescents have what % chance of being obese adults?
70-80%
95
Being overweight as young as age 18 could be the strongest predictor of what future surgery?
Hip replacement because of osteoarthritis
96
Obese children are how many times more likely to suffer a heart attack or stroke before they reach the adult age of 65?
3-5x
97
Maternal Obesity increases the risk of?
* ↑ risk for cesarean delivery,
gestational hypertension,
insulin-treated gestational diabetes, and hydramnios (inc. amniotic fluid)
* Increased risk for spontaneous abortion and miscarriage rates of almost double that of non-obese women in the first 6 weeks of pregnancy.
* Prolonged 1st (labor) and 2nd (pushing) Stage of Labor
98
Metabolic Syndrome in pregnancy manifests as:
Preeclampsia
Gestational HTN
Insulin Resistance
Diabetes
99
What are some increased postoperative complications in maternal obesity? What is NOT an increased risk?
wound infection and breakdown, endometritis,
antepartum venous thrombi/emboli
(VTE), and
excessive blood loss during surgery but
no increased risk of postpartum hemorrhage!
100
Treatments for Obesity
Multimodel. Dietary, increased exercise, behavior modification, drug therapy, and surgery.
101
When is drug therapy usually initiated in obese patients?
When BMI is > than 30kg/m^2 or a BMI between 27-29.9 with a coexisting medical condition.
102
What are some medications used to treat obesity?
* Gastrointestinal lipase inhibitors orlistat (Xenical) or (Alli) have been used to block the absorption of dietary fat
* Sympathomimetic amine/antiepileptic combo: phentermine/topiramate ER (Qsymia)
* GLP-1s - Ozempic
103
What are the 4 most common bariatric procedures: Restrictive or Malabsorptive Procedures
1) Laparoscopic adjustable gastric banding (LAGB)
2) Roux-en-Y gastric bypass (RYGB)
3) Laparoscopic sleeve gastrectomy (LSG) and 4) Biliopancreatic diversion with duodenal switch
104
What is a non-surgical (still procedure) option for obesity treatment?
Endoscopic space-occupying devices (intragastric balloons): FDA approved for 6- month implantation in patients within a BMI range of 30-40 kg/m2.
105
Indications for Bariatric Surgery
* BMI > 40 kg/m2
* BMI < 35 kg/m2 with an associated medical comorbidity worsened by
obesity
* Failed dietary therapy
* Psychiatrically stable without alcohol dependence or illegal drug use
* Knowledgeable about the operation and its sequelae
* Motivated individual
* Medical problems not precluding probable survival from surgery
106
Risk factors for postoperative bariatric surgery?
Men with high BMI
Htn, DM, postop leak w/ bariatric procedures, thromboembolism.
107
When does Maximum decrease in PaO2 occur after bariatric surgery?
2-3 days post op
108
Treatment/Prevention of bariatric surgery complications
avoid dehydration, hypovolemia, tubular obstruction, aciduria (administer fluids, bicarbonate, mannitol)
109
What to preoperative tests should be routine before a bariatric patient has surgery?
EKG and glucose testing due to risk of CV and DM
110
Most antibiotics in the bariatric surgery patient should be calculated on?
Total body weight
111
What EKG change is a marker/risk factor for sudden cardiac arrest in the severely obese?
Prolonged QT interval
112
What are some predictors of difficult intubation particularly in the obese patient?
Increased neck circumference (short neck)
Mallampatti > 3
Hx of OSA
Increased age
TMJ pathology
Edentulous
Beard (intubation and BVM)
Male sex
increased age (neck ROM)
113
Patient with recent gastric banding are at an increased risk of?
Aspiration so do an RSI
114
What is the ideal position to intubate an obese patient?
HELP position (Ramped)
Head elevated, laryngoscopy position
Head, upper body, and shoulders elevated above chest, connect sternal notch with external auditory meatus.
115
How many newtons of cricoid pressure should be at induction and after loss of consciousness during an RSI of an obese patient?
20N at induction
30N after loss of consciousness
(How the hell I'm supposed to know what 20 or 30 N is of pressure. I don't know.)
116
How can you position the patient utilizing the OR table to optimize obese patient induction?
30 degree
Reverse Trendelenburg (aka feet down)
or
Back of table elevated into bring whole upper body up
117
If you need to two hand mask ventilate because you don't have a coworker to help, how can you utilize the ventilator as your second person?
Turn ventilator on to deliver positive pressure breaths while you hold BVM tightly on patient face if you don't have face straps. (genius, wtf)
118
What position should the obese patient be in during induction / extubation? What does this promote?
Position pt in reverse trendelenburg for induction/extubation.
Promotes pt comfort, reduces gastric reflux, easier mask ventilation, improves respiratory mechanics, helps maintain FRC. (These pts probably do not lay flat at home, at least not comfortable)
119
General anesthesia causes what % decrease in FRC in obese patients ?
50%!
120
Current ventilation recommendations for the obese patient, (and not obese patient I would assume?)
Tidal volume *6*-10mL/kg of IDEAL body weight (avoid barotrauma)
Pressure Control Ventilation with volume guarantee
121
How does blood volume change in the obese patient? How does this change your estimated blood volume calculation?
Estimated blood volume is decreased
EBV calculation: 45-55mL/kg of actual body weight (normal is 70mL/kg)
122
Severely obese total body water is what percent? Normal adult total body water is?
Severely obese, TBW is 40%
Normal adult is 60-65%
123
Fluid management in the severely obese patient is guided by?
BP, HR, and UO - (obviously, more invasive or better indicator of fluid responsiveness is ideal. However, important to remember that these patients likely have hypertension at baseline and a decreased total body water and so I want to maintain renal perfusion and prevent PONV. )
124
Decision to extubate obese patient depends on:
-Ease of BVM ventilation and intubation prior
-Length and type of surgery (anything over ~4 hrs has increased post op risk)
-Presence of existing conditions (OSA, COPD, etc)
-Extubate patient sitting up
-if in doubt, keep intubated, extubate over an airway exchange or fiberoptic bronchoscope, or OPA or NPA
-Awake, not a deep extubation
125
Compared to nonobese patients, obese patients require how much more or less local anesthetic for spinal or epidurals?
Require ~25% less d/t more epidural fat and distended epidural veins
