obstructive sleep apnea and obesity hypoventilation syndrome

Question 1

breath cessation for at least 10 sec

Answer 1

apnea

Question 2

decrement in airflow with drop of oxygen saturation of at least 4%

Answer 2

hypopnea

Question 3

ventilatory effort is absent for the duration of the apneic episode

Answer 3

central apnea

Question 4

Ventilatory effort is absent in first portion followed by its reappearance during the apneic episode

Answer 4

mixed apnea

Question 5

Ventilatory effort persists throughout the apneic episode, but no airflow occurs because of transient obstruction of the upper airway

Answer 5

Obstructive apnea

Question 6

Obstructive and mixed sleep apneas are more common and may be associated with daytime somnolence that impacts quality of life and, in severe form, is associated with severe hypoxemia during sleep that may cause:

Answer 6

◦ Life-threatening issues cardiac arrhythmias
◦ Pulmonary HTN
◦ Right-sided heart failure
◦ Systemic HTN
◦ Secondary erythrocytosis

Question 7

Sleep disorder characterized by repetitive complete (apneas) or partial (hypopnea) upper airway
collapse

Answer 7

obstructive sleep apnea (OSA)

Question 8

obstructive sleep apnea can lead to

Answer 8

◦ recurrent arousals and cyclical hypoxemia
◦ chronic and sustained systemic and pulmonary HTN and arrhythmias

Question 9

complete cessation of airflow for ≥ 10 seconds

Answer 9

apnea

Question 10

partial airflow obstruction often resulting in arousal from sleep

Answer 10

hypopnea

Question 11

number of apneas and/or hypopneas per hour of sleep

Measured via sleep study (in-lab polysomnography or home study)

Answer 11

Apnea-hypopnea index

Question 12

OSA- Risk Factors

Answer 12

Obesity
Large neck circumference
Male sex
Older age
Snoring
Cigarette smoking
Use of alcohol or sedatives before sleeping
Craniofacial abnormalities
Endocrinopathies
◦ Acromegaly
◦ Hypothyroidism
◦ Primary aldosteronism
More common among Asian, Black, Native American, and Hispanic ethnicities

Question 13

partial obstruction of the airway

Answer 13

snoring

Question 14

complete obstruction of the airway

Answer 14

OSA

Question 15

suspect in pts presenting with:
◦ Snoring
◦ Witnessed breathing pauses
◦ Restless or nonrefreshing sleep
◦ Awakenings (with gasping or paroxysmal nocturnal dyspnea)
◦ Insomnia
◦ Excessive daytime sleepiness or fatigue

Answer 15

OSA

Question 16

◦ Patient-reported questionnaire which may be used to assess patient’s perception of sleepiness
The USPSTF does not recommend screening asymptomatic adults for sleep apnea

• how likely they are to doze of in different situations

Answer 16

epworth sleepiness scale for OSA

Question 17

Modified Mallampati score 3-4 (low visibility of posterior pharynx when patient opens mouth)
Retrognathia or increased overjet (top incisor teeth ahead of bottom incisors)
Lateral peritonsillar narrowing
Macroglossia
Tonsillar hypertrophy
Elongated or enlarged uvula
High-arched or narrow hard palate
Nasal abnormalities (polyps, deviated septum, turbinate hypertrophy)
Measure neck circumference (“bull neck”)

Answer 17

OSA physical exam

Question 18

complete visualization of the soft palate

Answer 18

mallampati score: Class 1

Question 19

complete visualization of the uvula

Answer 19

mallampati score: Class 2

Question 20

visualization of only the base of the uvula

Answer 20

mallampati score: Class 3

Question 21

soft palate is not visible at all

Answer 21

mallampati score: Class 4

Question 22

abnormally large tongue

Answer 22

macroglossia

Question 23

OSA diagnostics

Answer 23

in lab polysomnography (PSG) (sleep study)- “gold standard” diagnostic test

Confirmed by number of obstructive events (apnea, hypopnea, or respiratory event-related arousal) on PSG is ≥ 5 events/hour (with symptoms) OR >15 events/hour (without symptoms)

Question 24

OSA severity (respiratory disturbance index- (RDI)

Answer 24

◦ Mild
◦ RDI ≥ 5 events/hour and < 15 events/hour
◦ Moderate
◦ RDI ≥ 15 events/hour and < 30 events/hour
◦ Severe
◦ RDI ≥ 30 events/hour

Question 25

In those with OSA and HTN

Answer 25

screen for primary aldosteronism

Question 26

OSA- Treatment

Answer 26

CPAP (steady steam of air from mask that opens airway)

• weight reduction in obese individuals
• avoid alcohol and hypnotics
• oral appliances
• modafinil- improves daytime sleepiness

surgical procedures if
◦ Obvious anatomical obstructions
◦ Fail or do not tolerate initial therapy with CPAP or MAD

Question 27

OSA follow up

Answer 27

◦ Polysomnography should be performed to assess improvement in disease severity

Question 28

PICKWICKIAN SYNDROME OR HYPERCAPNIC SLEEP APNEA

Answer 28

obesity hypoventilation syndrome

Question 29

Chronic condition characterized by:
◦ Obesity
◦ Daytime hypoventilation
◦ Sleep-disordered breathing
May result in respiratory, metabolic, and cardiovascular impairments
Caused by a failure of normal compensatory mechanisms to counterbalance consequences of
excess weight on the respiratory system

Answer 29

obesity hypoventilation syndrome (OHS)

Question 30

OHS risk factors

Answer 30

Risk Factors
Obesity (esp. BMI >40)
Preexisting OSA
◦ Most patients with obesity-hypoventilation syndrome also suffer from OSA (90% of patients)
◦ Must be treated aggressively if comorbid disorder

Question 31

OHS Diagnostic Criteria

Answer 31

BMI ≥ 30

Hypoventilation during awake hours- characterized by:
◦ Hypercapnia
◦ Serum bicarbonate level is supportive

Sleep disordered breathing diagnosed by polysomnography

Exclusion of other causes of alveolar hypoventilatio

Question 32

OHS- History

Answer 32

Patients may have symptoms consistent with nocturnal hypoventilation:
◦ Waking headaches
◦ Peripheral edema
◦ Hypoxemia (arterial oxygen saturation <94% on room air)
◦ Unexplained polycythemia
Stable patients may have symptoms consistent with OSA (reported in up to 90%)

Question 33

General
◦ BMI- ≥ 30
◦ Breathing pattern- may be shallow and rapid
Neck
◦ Circumference
◦ Large neck circumference (mean neck circumference 42.2 cm with OHS vs. 40 cm with OSA)
◦ Jugular venous distention?
◦ Right heart failure?
Extremities
◦ Peripheral edema
◦ Right heart failure?

Answer 33

OHS PE

Question 34

OHS- Work-Up

Answer 34

Arterial blood gas
Overnight in-lab polysomnography
Daytime finger pulse oximetry
PFTs
ECG and TTE
TSH
Hemoglobin

Question 35

OHS- Treatment

Answer 35

Goals: normalize sleep breathing, reduce weight, improve respiratory drive

CPAP is first line

Avoidance of:
◦ Sedative hypnotics
◦ Alcohol
◦ Opioids
Adjunct therapy:
◦ Dietary consult
◦ Physical activity
◦ Oxygen
Non-invasive ventilation for respiratory failure
Bariatric surgery

Question 36

Patients with OHS have higher risk of complications in the perioperative period including:

Answer 36

◦ Respiratory failure
◦ Intubation
◦ HF