Obstructive Sleep Apnea

Question 1

RERA

Answer 1

respiratory effort-related arousals

Question 2

apnea vs hypopnea

Answer 2

apnea - breathing pauses lasting at least 10 seconds

hypopnea - 50%-30% reduction of airflow lasting at least 1 seconds with 3-4% drop on o2 sat

Question 3

pathophysiology of OSA

Answer 3

collapse of flexible musculature of upper airway during sleep leads to reduced or absent airlow despite continued respiratory effort

Question 4

what are some conditions associated with OSA

Answer 4

obesity, a fib, resistant HTN, ACS, CHF, t2dm, stroke, pulmonary htn

Question 5

Suspect OSA on history, how to confirm diagnosis?

Answer 5

PSG (polysomnography) with CPAP titration

also helps determine severity of OSA

Question 6

What parts of the hx can suggest OSA?

Answer 6

snoring, excessive daytime sleepiness, gasping for air, witnessed apneas, tired despite 7-8 hours of sleep, concentration/memory/attention problems

Question 7

What is the most widely used scale to assess fatigue/sleepiness

Answer 7

Epworth Sleepiness Scale

can also use Stanford Sleepiness Scale and Fatigue Severity Scale

Question 8

Physical exam findings indicative of OSA

Answer 8

BMI>30, HTN, retrognathia, thick neck, macroglossia, thyroid enlargement, enlarged uvula, large tonsils

Question 9

Ddx for OSA

Answer 9

snoring
narcolepsy
pulmonary disease
periodic limb movements of sleep
shift workers syndrome
obesity hypoventilation syndrome (can have concomitant OSA)

Question 10

Components of PSG

Answer 10

EEG, ECG, electroculogram (EOG), chin electromyogram (EMG), airflow, 02 sat

Question 11

apnea hypopnea index (AHI)

Answer 11

number of apnea and hypopnea episodes per hour of sleep

Question 12

respiratory disturbance index

Answer 12

number of apnea, hypopnea, and repsiratory effort related arousal (RERA) episodes per hour of sleep

Question 13

Dx criteria for OSA

Answer 13

AHI or RDI of at least 15 defined by at least 15 obstructive events per hour on PSG with or without symptoms

or

AHI/RDI of at least 5 + SYMPTOMS (daytime sleepiness, unrefreshing sleep, fatigue, insomnia, nighttime awakenings or witnessed loud snoring/breathing interruptions)

Question 14

treatment of choice for all severities

Answer 14

positive airway pressure PAP

Question 15

What is the connection smoking and development of sleep apnea

Answer 15

direct correlation

increased risk of sudden cardiac death

Question 16

When to re-evaluate for continued therapy or PAP adjustment

Answer 16

after weight loss

all patients should be educated on lifestyle modifications (weight loss, driving safety, avoidance of alcohol or sedating meds, smoking cessation)

Question 17

How does PAP work?

Answer 17

maintain patency of upper airway to reduce AHI

Question 18

How to determine level of PAP

Answer 18

in-lab attended overnight PSG and/or split night diagnostic and titration study

Question 19

When to use oral appliances

Answer 19

mild-moderate OSA or who have contraindication to PAP, or if PAP + behavioral modification don’t work

Question 20

When to use surgery

Answer 20

can be primary therapy if OSA is mild, resistant to PAP, and when there is an anatomic cause of major airway obstruction that can be reversed

Question 21

Mallampati score

Answer 21

degree of neck thickness as suggested by visibility of palate

Out of 4, score>3 suggestive of OSA

Question 22

How to improve comfort of PAP machine

Answer 22

heated humidification…if that fails, try different mask or pressure relief…if that fails try alt therapy like oral appliance or surgery