Obesity Flashcards
Is the single best predictor of problematic intubation in morbidly obese patients.
Neck circumference
Is the only ventilatory parameter that has consistently been shown to improve respiratory function in obese patients
PEEP
It is the weight associated with the lowest mortality rate for a given height and gender.
How do you calculate this?
IBW
Height cm - x (100 for males, 105 for females)
Is a similar concept as the IBW, and more commonly used in the medical literature.
How to calculate?
Predicted body weight
Males = 50 + 0.91 × (height (cm) − 152.4)
Females = 45.5 + 0.91 × (height (cm) − 152.4)
Is the total body weight (TBW) minus the adipose tissue.
Lean body weight
Males: 1.10 × TBW − 0.0128 × BMI × TB
Females: 1.07 × TBW − 0.0148 × BMI × TBW
BMI
- Obese
- Morbid obesity
- Super obese
- Super-super obese
- 30
- 40
- 50
- 60
Is primarily a noradrenergic and possibly dopaminergic sympathomimetic amine that decreases appetite. Although it is only approved for 3 months’ use, it can induce, tachycardia, palpitations, and hypertension, as well as dependence, abuse, and withdrawal symptoms.
It is now being combined with?
Phentermine (Adipex-P)
topiramate (Topamax)
Is a serotonin receptor antagonist and stimulates the serotonin type 2c receptor.
Lorcaserin
Is combined with naltrexone and is a dopamine and norepinephrine reuptake inhibitor which stimulates pro-opiomelanocortin neurons.
Bupropion
Is currently the most effective treatment for morbid (class III) obesity.
Bariatric surgery
Is currently the most effective treatment for morbid (class III) obesity.
Recommended for BMI of? (2)
Bariatric surgery
- 40 kg/m2
- 35 mg/m2 with obesity-related comorbidities
Are the most commonly reported abnormalities of pulmonary function in obese patients. (2)
- Decreased FRC
2. Decreased ERV
How much reduction of FRC occur in obese patients during anesthesia?
50%
Is the most sensitive indicator of the effect of obesity on pulmonary function.
ERV
The gold standard technique for diagnosing OSA is?
Overnight polysomnography
Is a combination of obesity and chronic hypoventilation that is frequently misdiagnosed and untreated, resulting in pulmonary hypertension and cor pulmonale, increased risk of postoperative complications, and death.
What are the diagnostic s/sx (3)?
Obesity hypoventilation (Pickwickian) syndrome (OHS)
- BMI >30
- Awake arterial hypercapnia (>45 paco2)
- No known causes of hypoventilation
Read
Obese patients have mild to moderate hypertension, with a 3 to 4 mmHg increase in systolic and a 2 mmHg increase in diastolic arterial pressure for every 10 kg of weight gained. Normotensive obese patients have reduced systemic vascular resistance, which rises with the onset of hypertension.
Plays a major role in the hypertension of obesity by increased circulating levels of angiotensinogen, aldosterone, and angiotensin-converting enzyme.
RAAS
What clotting factors are increased in obese patients? (5)
- Fibrinogen
- VII
- VIII
- vWf
- PAI-1
Which clotting factor is correlatec with increased cardiovascular mortality.
VIII
An increase of more than ___ kg/m2 in BMI is associated with a 2.7-fold increase in risk for developing new reflux symptoms.
3.5
MC biochemical abnormality in obese?
Inc in ALT
Read
Obesity is associated with glomerular HYPERFILTRATION as evidenced by increased renal blood flow and increased glomerular filtration rate.
Components of metabolic syndrome or syndrome x Accdg to the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) 3 out of 5 conditions defines this syndrome
- Central obesity: Waist circumference 102 cm or more (≥40 in) in males, 88 cm or more (≥35 in) in females
- Dyslipidemia: Triglycerides 150 mg/dL or more; (3) Dyslipidemia: HDL 40 mg/dL or less in males, 50 mg/dL or less in females
- Hypertension : at least 130/85 mmHg or use of antihypertensive
- Dyslipidemia: Triglycerides 150 mg/dL or more
- Elevated glucose
Read
A drug that is mainly distributed to lean tissues should have the loading dose calculated based on LBW.
If the drug is equally distributed between adipose and lean tissues, dosing should be calculated based on TBW.
For maintenance, a drug with similar clearance values in both obese and nonobese individuals should have the maintenance dose calculated based on?
LBW
However, a drug whose clearance increases with obesity should have the maintenance dose calculated according to TBW.
Increased redistribution of a drug prolongs its elimination half-life even when clearance is unchanged or increased. Hyperlipidemia and an increased concentration of α1-acid glycoprotein may affect protein binding, leading to a reduction in free drug concentration.
Plasma albumin and total plasma protein concentrations and binding are not significantly changed by obesity, but when compared with normal-weight individuals, a relative increase in plasma protein binding may be evident.
Read
Drugs that undergo phase I metabolism (oxidation, reduction, hydrolysis) are generally unaffected by changes induced by obesity, whereas phase II reactions (glucuronidation, sulfation) are enhanced.
Is renal clearance decreased or increased in obesity?
What 2 drugs needs increased dosing?
Renal clearance of drugs is increased in obesity because of increased renal blood flow and glomerular filtration rate
drugs such as cimetidine and aminoglycoside antibiotics that depend on renal excretion may require increased dosing
Less lipophilic compounds have little or no change in VD with obesity. Exceptions to this rule include the highly lipophilic drugs (3)
- Digoxin
- Procainamide
- Remifentanil
The authors recommend sugammadex dosing be based on?
Actual body weight
Drugs using TBW
- Propofol (maintenance)
- Succinylcholine (pseudocholinesterase activity increases)
- Dexmedetomidine
- Neostigmine
- Sugammadex
4 factors significant to develop DVT in obese patients
- Venous stasis disease
- BMI 60 or more
- Central obesity
- OHS/OSA
Is the most common mononeuropathy after bariatric surgery.
Carpal tunnel syndrome
Read cuff measurements with obese patients
Cuffs with bladders that encircle a minimum of 75% of the upper arm circumference or, preferably, the entire arm, should be used.
What estimates normovolemia in obese patients?
The use of IBW estimates and appropriate monitoring can help to avoid potential hyperhydration in morbidly obese patients.
Preliminary findings demonstrate that during laparoscopic bariatric surgery, urine output does not correlate with the rate of intraoperative fluid administration, and the total volume of fluids infused does not seem to affect the incidence of postoperative rhabdomyolysis.
What is the only ventilatory parameter consistently shown to improve respiratory function in obese subjects.
PEEP
What factor is significantly related to block failure in epidural anesthesia?
Increased maternal BMI
Height of an epidural block for a given volume of local anesthetic is proportional to 2 factors
BMI
Maternal weight
Local anesthetic dosing should be based on?
Ideal body weight
The most common postoperative complications are (3)
- respiratory (atelectasis, pneumonia)
- vascular (thrombophlebitis, DVT)
- wound complications (infection, dehiscence)