Obesity Flashcards
How do you calculate ideal body weight?
Male: 105 lb + 6 lb for each inch over 5ft
Female: 100 lb + 5 lb for each inch over 5 ft
How do you calculate BMI?
weight (kg)/ height (meters) ^2
What BMI is considered overweight? Obese? Morbidly obese? Super-obese?
Overweight: 25-29
Obese: 30 or greater
Morbidly obese: 40 or greater
Super-obese: 50 or greater
What are some negative outcomes associated with obesity?
- Increased incidence of diabetes and cardiovascular disease
- Difficult tracheal intubation
- Decreased PaO2
- Increased gastric volume
- Decreased gastric pH
- Increased post-op would infection
- Increased risk of pulmonary embolism
- Increased risk of sudden death
- Worse 30 day outcomes
What are some side effects of obesity on the respiratory system?
- Obstructive sleep apnea
- Obesity hypoventilation syndrome
- Restrictive lung disease
What are some side effects of obesity on the cardiovascular system?
- Systemic hypertension
- Cardiomegaly
- Congestive heart failure
- Ischemic heart disease
- Cerebrovascular disease
- Peripheral vascular disease
- Pulmonary hypertension
- Deep vein thrombosis
- Pulmonary embolism
- Hypercholesterolemia
- Hypertriglyceridemia
What are some side effects of obesity on the endocrine system?
- Diabetes mellitus
- Cushing syndrome
- Hypothyroidism
What are some side effects of obesity on the GI system?
- Hiatal hernia
- Gallstones
- Fatty liver infiltration
- GERD
- Increased gastric volume and intra-gastric pressure
- Gastric acidity
- Gastric emptying delays-greater residual volumes
- High risk for aspiration pneumonitis when gastric volumes are greater than 25 ml or pH is less than 2.5
What are some side effects of obesity on the musculoskeletal system?
- Osteoarthritis of weight-bearing joints
- Back pain
What are some malignancies associated with obesity?
- Breast
- Prostate
- Cervical
- Uterine
- Colorectal
What respiratory changes occur as a result of obesity?
- FRC reduced
- ERV reduced
- TV may fall close to closing capactity
- Increased O2 consumption and CO2 production
- High minute ventilation
- Reduced chest wall compliance
- Increased respiratory resistance-restrictive lung pattern
- As obesity worsens you will see lung disease and pulmonary hypertension. PFTs may remain normal until this occurs
In the obese patient in what positions are respiratory changes exaggerated and what effects are seen?
- Supine and trendelenberg
- V/Q mismatch
- hypoxemia
- Increased right to left shunt
What are some difficulties cased by abundant soft tissue in the upper airway?
- Obstruction of the airway
- Impairment of mandible and cervical mobility
- Difficulty maintaining mask airway
- Difficult laryngoscopy and intubation (consider riber optic intubation)
What cardiovascular changes occur as a result of obesity?
- Cardiac output is increased
- Increase in circulating blood volume (can cause strain on myocardium)
- Arterial hypertension risk is doubled
- Risk of CAD is doubled and presents with angina, CHF, acute MI and sudden death
- Increased left-sided heart pressures and left ventricular hypertrophy
- Limited reserve for hypotension, hypertension, tachycardia, fluid overload
What can hyperlipidemia lead to?
- Increased LDL/Decreased HDL linked to atherosclerosis
- Premature coronary artery disease
- Premature vascular disease
- Pancreatitis
How is obstructive sleep apnea characterized?
- Apnea for longer than 10 seconds despite respiratory effort against a closed glottis
- Hypopnea partial or intermittent closure or narrowing of the upper airway during sleep resulting in a 4% decrease in arterial oxygen saturation
How is OSA diagnosed?
-At least 5 episodes of apnea, hypopneas, or both during 1 hour
How is OSA graded?
Mild: greater than 5 but less than 15 episodes of apnea and/or hypopnea an hour
Moderate: 15 to 30 an hour
Severe: greater than 30 an hour
What are risk factors for OSA?
- Middle age
- Male
- Obesity (BMI > 30)
- ETOH use
- Drug induce sleep aids
- Abdominal fat distribution
- Neck girth (41cm) (greater than 17 inches for men or greather than 16 inches for women)
What does OSA result in?
- Hypoxemia
- Right heart failure
- Hypercapnea
- Pulmonary and systemic vasoconstriction
- Polycythemia
- Respiratory acidosis during sleep
- Arterial hypoxemia
- Systemic hypertension
- Pulmonary hypertension
What pre-op questions should be asked to screen for OSA?
- Sleeping patterns?
- Snoring?
- Daytime somnolence?
What is obesity hypoventilation syndrome/Pickwickian syndrome?
- Long term consequence of OSA
- As OHS develops you get nocturnal central apnic events
What are the characteristics of obesity hypoventilation syndrome?
- Obesity
- Hypercapnia
- Daytime hyper-somnolence
- Arterial hypoxemia
- Pulmonary hypertension
- Respiratory acidosis
- Right sided heart failure
- Airway difficulty
What are some thromboembolic characteristics associated with obesity?
- Risk of DVT is doubled
- Polycythemia
- Increased intra-abdominal pressure
- Immobility
