SM 185 Sleep

Question 1

What is sleep?

Answer 1

A rapidly reversible state of reduced responsiveness and motor activity

Question 2

What is sleep good for?

Answer 2

Memory consolidation, energy conservation, brain restoration, and immune function

Question 3

What are the stages of sleep?

Answer 3

Awake, Non REM 1, Non REM 2, Nom REM 3, REM

Question 4

Which stage of sleep is most prominent early in the sleep cycle?

Answer 4

Stage 3 Non REM is most prominent early in the night

Question 5

Which stage of sleep is most prominent late in the sleep cycle?

Answer 5

REM sleep is most prominent late in the night

Question 6

What are the two types of sleep apnea?

Answer 6

Obstructive sleep apnea and central sleep apnea

Question 7

How do the Bernoulli Principle and the Venturi Effect tie into Obstructive Sleep Apnea?

Answer 7

The Bernoulli Principle states that fluid flow is higher with smaller areas, while the Venturi Effect states that fast fluid flow is associated with lower pressure

Therefore, narrow parts of the airway experience faster flow and lower pressure, predisposing obstruction

Question 8

How does lower pressure in the airway lead to obstruction?

Answer 8

Lower airway pressure exacerbates compressive forces from the surrounding tissue, and can result in a flap of tissue obstructing the airway

Question 9

Describe the prevalence of Obstructive Sleep Apnea?

Answer 9

Obstructive Sleep Apnea can occur at any stage of life and is more common in men

Question 10

Anatomically, what predisposes Obstructive Sleep Apnea?

Answer 10

Oropharyngeal crowding can impede airflow, which is due to excessive tissue in the mouth, micrognathia, macroglossia, and impaired Oropharynx muscular tone

Question 11

How does excessive tissue predispose Obstructive Sleep Apnea?

Answer 11

Extra tissue makes it more likely the airway will be obstructed

Question 12

How does Micrognathia predispose Obstructive Sleep Apnea?

Answer 12

Micrognathia = small chin, makes it easier for the airway to be blocked

Question 13

How does Macroglossia predispose Obstructive Sleep Apnea?

Answer 13

Macroglossia = large tongue, which is more likely to block the airway

Question 14

How does impaired Oropharynx muscular tone predispose Obstructive Sleep Apnea?

Answer 14

Lower muscle tone makes it more likely for the airway to collapse

Question 15

What is a Mallampati score and what is it used for?

Answer 15

Mallampati scores are assessments of the airway and how open it is; Class 1 = normal and Class 4 = most obstructed

Question 16

What factors may predispose Obstructive Sleep Apnea?

Answer 16

Obesity, familial inheritance, and certain minority groups

Question 17

How do obesity rates correspond with Obstructive Sleep Apnea rates?

Answer 17

Higher obesity rate = higher Obstructive Sleep Apnea rate

Question 18

How do sex hormones mediate Obstructive Sleep Apnea?

Answer 18

Testosterone exerts central effects that make Obstructive Sleep Apnea more likely, while Estrogen protects against Obstructive Sleep Apnea

Question 19

When are women more at risk for Obstructive Sleep Apnea and why?

Answer 19

Post menopausal women are more at risk for Obstructive Sleep Apnea because they lose the protective effects of Estrogen

Question 20

What are symptoms of Obstructive Sleep Apnea?

Answer 20

Unrefreshing sleep, daytime sleepiness, AM headache, vivid dreams, snoring

Question 21

Why does Obstructive Sleep Apnea cause snoring?

Answer 21

Airflow is impeded by tissue in Obstructive Sleep Apnea, so snoring is caused by the airflow forcing the tissue flap open

Question 22

How is OSA screened for?

Answer 22

Screening tools for OSA include questionnaires

Question 23

How is OSA diagnosed?

Answer 23

Polysomnography is the gold standard for Obstructive Sleep Apnea diagnosis

Question 24

What does Polysomnography involve?

Answer 24

Polysomnography involves an EEG, EOG, EKG, abdominal belt and pulse ox to determine when airflow stops and whether or not efforts to breath stop as well

Question 25

How can an apnea be distinguished as Obstructive on a Polysomnograph?

Answer 25

Look for a flat airflow (no airflow) in the presence of diaphragmatic excursions (diaphragm activity), which indicates the patient is trying to breath but unable to due to the obstruction = Obstructive Sleep Apnea

Question 26

How long must an apnic episode last to be considered apnea?

Answer 26

Obstructed airflow for at least 10s due to obstruction of the upper airway

Question 27

How does Obstructive Sleep Apnea affect the heart?

Answer 27

Upper airway obstruction leads to a negative intrathoracic pressure on inspiration, raising the venous return and increasing transmural pressure, leading to greater LV afterload

Question 28

How does Obstructive Sleep Apnea effect the LV afterload?

Answer 28

Increased LV Afterload

Question 29

How does Obstructive Sleep Apnea respond to hypoxia?

Answer 29

Since Obstructive Sleep Apnea causes hypoxia by restricting airflow, pulmonary vasocontriction occurs, leading to RV dilation and impingement on the LV, decreasing LV filling and lowering LV output

Question 30

How does Obstructive Sleep Apnea effect the RV?

Answer 30

Obstructive Sleep Apnea causes hypoxia, which results in vasoconstriction of the pulmonary bed; in turn, this leads to increased RV afterload, causing RV dilation and impingement on the LV, lowering CO

Question 31

How does Obstructive Sleep Apnea affect the cardiovascular system as a whole?

Answer 31

Hypoxemia, sustained catecholamine release from increased sympathetic tone, increased endothelin secretion, and overall a pro-inflammatory state ensues

Question 32

How does Obstructive Sleep Apnea effect nocturnal blood pressure?

Answer 32

Normally, BP drops in sleep; Obstructive Sleep Apnea results in the normal blood pressure drop disappearing

Question 33

How does Obstructive Sleep Apnea effect Cardiovascular Risk?

Answer 33

Increased risk of CV events, independent of obesity and other shared risk factors, with higher levels of Troponin and worse outcomes for patients with CAD

Question 34

What arrhythmia can Obstructive Sleep Apnea precipitate?

Answer 34

Obstructive Sleep Apnea can cause a greater risk for Atrial Fibrillation and Tachy-Brady syndrome

Question 35

If someone has AFib, what can be modified about them related to sleep?

Answer 35

AFib correlates with Obstructive Sleep Apnea, so send the patient in for a sleep evaluation to try and improve the sleep disorder and improve the AFib

Question 36

What receptor mediates Cheyne-Stokes respirations?

Answer 36

C-fibers mediate Cheyne-Stokes respirations

Question 37

What are Cheyne-Stokes respirations?

Answer 37

Irregular breathing that act as a sign of PCO2 response dysregulation

Question 38

What pulmonary symptom is frequently present in Obstructive Sleep Apnea?

Answer 38

Pulmonary Hypertension is common in people with Obstructive Sleep Apnea, and worsens existing lung disease

Question 39

What is the single best way to improve sleep apnea?

Answer 39

Weight loss has the biggest impact, but is the least often achieved measure

Question 40

What sleeping position worsens sleep apnea?

Answer 40

Sleeping while supine worsens sleep apnea; some therapies alter sleeping position in patients with mild/moderate Obstructive Sleep Apnea to improve the disease

Question 41

How do dental appliances alter sleep apnea?

Answer 41

Dental appliances can improve airflow by reducing obstruction in the oropharynx

Question 42

What is CPAP?

Answer 42

Continuous Positive Airway Pressure, which uses a machine to act like a stent and keep the airways patent, preventing obstruction

Question 43

What is APAP?

Answer 43

Auto-titrating CPAP; normal CPAP does not sense nasal airflow and is unable to adjust pressure to maintain flow, while APAP is ale to adjust airflow

Question 44

When is Central Sleep Apnea?

Answer 44

Sleep Apnea due to an issue with the brain or sensation

Question 45

How can Central Sleep Apnea be diagnosed from a Polysomnograph?

Answer 45

If airflow decreases without an increase in diaphragmatic excursion, this suggests that no attempt is being made to maintain airflow and that a brain or sensation issue is at play = Central Sleep Apnea

Question 46

How can Obstructive Sleep Apnea and Central Sleep Apnea be distinguished on a Polysomnograph?

Answer 46

Central Sleep Apnea = no airflow + no diaphragm movement, Obstructive Sleep Apnea = no airflow + increased diaphragm movement

Question 47

What underlies Central Sleep Apnea?

Answer 47

Abnormal ventilatory control