SM_185a: Sleep Disorders

Question 1

Obstructive sleep apnea is an issue with the _______

Answer 1

Obstructive sleep apnea is an issue with the airway

Question 2

The physics of obstructive sleep apnea involves the ______ and the ______

Answer 2

The physics of obstructive sleep apnea involves the Bernoulli principle and the Venturi effect

• Bernoulli principle: the faster a fluid flows in a rigid nonrigid tube, the more negative pressure it will create
• Venturi effect: going from a tube with larger to tube with smaller cross-sectional area, velocity increases and pressure decreases

Question 3

In OSA, ______ of the upper airway will lead to ______ pressure, causing the upper airway to collapse

Answer 3

In OSA, narrowing of the upper airway will lead to negative pressure, causing the upper airway to collapse

Question 4

The highest prevalence of OSA is in ______ [with/without] _______

Answer 4

The highest prevalence of OSA is in men without daytime sleepiness

(then women without daytime sleepiness)

Question 5

_______ is an anatomical risk factor for OSA because it _______

Answer 5

Oropharyngeal crowding is an anatomical risk factor for OSA because it impedes airflow

• Excessive tissue (obesity, tonsillar hypertrophy, etc)
• Micrognathia
• Macroglossia
• Impaired OP muscular tone

Question 6

Describe the symptoms of OSA

Answer 6

OSA symptoms

• Unrefreshing sleep
• Daytime sleepiness/fatigue
• Morning headache
• Memory and learning impairments
• Hyperactivity
• Insomnia
• Vivid dreams
• Snoring

Question 7

OSA is diagnosed through ______

Answer 7

OSA is diagnosed through polysomnography

Question 8

OSA is characterized by _____ but ______ on polysomnography

Answer 8

OSA is characterized by absent airflow but active effort (diaphragmatic excursions)

Question 9

Long-term effects of OSA broadly include _____, _____, and _____ effects

Answer 9

Long-term effects of OSA broadly include effects on cardiovascular, cognitive, and quality of life effects

Question 10

Cardiopulmonary effects of OSA are _____ and _____

Answer 10

Cardiopulmonary effects of OSA are upper airway obstruction and hypoxia

• Upper airway obstruction: negative intra-thoracic pressure, increased transmural pressure, increased LV afterload, increased venous return
• Hypoxia: pulmonary vasoconstriction, septal bowing into LV, decreased LV filling, decreased SV

Question 11

Which mechanisms cause the cardiac of OSA?

Answer 11

OSA cardiac effects mechanisms

• Hypoxemia
• Repeated arousals
• Sustained increased catecholamine levels
• Increased sympathetic tone
• Increased endothelin secretion
• Alterations in eicosanoids

Question 12

Describe the coronary effects of OSA

Answer 12

Coronary effects of OSA

• Increased risk of CV events in severe OSA
• Worse outcomes for patients with known CAD and OSA
• Higher levels of troponin-I in severe OSA: low level, chronic myocardial injury

Question 13

Describe the arrhythmic effects of OSA

Answer 13

OSA arryhthmic effects

• 4x higher risk of AFib associated with OSA
• May be modifiable risk factor for AFib recurrence after cardioversion
• Tachy-brady syndrome common during apneic episodes in OSA

Question 14

_____ are a sign of dysregulation of the body’s normal response to P_CO2 levels in OSA

Answer 14

Cheyne-Stokes respirations are a sign of dysregulation of the body’s normal response to P_CO2 levels in OSA

(start breathing, then pause, then try to breathe)

Question 15

Describe the relationship between OSA and pulmonary hypertension

Answer 15

• Pulmonary HTN present in 20% of OSA patients, especially those with concommitant lung didease
• Associated with worse prognosis and decreased exercise tolerance and quality of life

Question 16

Central apnea is an issue with the ______ and is characterized by ______ ____ active effort (diaphragmatic excursions) on polysomnography

Answer 16

Central apnea is an issue with the brain/controller and is characterized by absent airflow without active effort (diaphragmatic excursions) on polysomnography