SLEEP DISORDERED breathing

Question 1

•Flow through the upper airway during sleep can be predicted using a Starling resistor model, where flow through a tube is predicted by pressures and resistances upstream and downstream to the site of collapse. During an obstructive event, what is the relationship between the pressures at the site of airway collapse (Pcrit), upstream (Pus) to the site of collapse, and downstream (Pds) to the site of collapse?

A.Pus> Pcrit> Pds.
B.Pus> Pds> Pcrit.
C.Pcrit> Pus> Pds.
D.Pcrit> Pds > Pus.

Answer 1

answer = c

outside pressure causing collapse of the airway

Question 2

Primary muscles of sleep

Answer 2

1) muscles influencing hyoid position (geniohyoid/sternohyoid)
2) tongue muscles (genioglossus)
3) palate muscles (tensor palatini, levator palatini)

Question 3

Effect of obesity on airway

Answer 3

1) airway narrowed due to incr fatty tissue around neck
2) causes collapse of pharyngeal space
3) compensate by incr force of genioglossus muscle

Question 4

Physics of upper airway collapse

Question 5

Snoring

1) what proportion of people occassionally?
2) habitual in men vs women

Answer 5

universal

44% men, 28% women

Question 6

cheyne-stokes respiration

found in which patients?

what happens?

arounds occur when?

Answer 6

heart failure, storke

greater hypercaneic respiratory drive –> overshooting of PaCO2 below apneic threshold

1) CO2 = primary drive of breathe

2) CO2 in blood decr and delayed incr in resp neurons
(aortic and carotid bodies and medulla)

3) exaggerated response and overshoot target
blow down CO2 too low so long pause

when CO2 rise then breathe again

–> arousals occur at peak of ventilation

Question 7

•A 62 year old man presents to clinic with the chief complaint of daytime sleepiness for the past 6 months. He is unable to stay awoke while watching television in the evening and his wife is concerned about his driving. His wife also states that he struggles to breath during sleep. He has a history of hypertension and diabetes. His Body Mass Index is 38 and neck circumference is 56cm. Which of the following diagnostic tests would provide the definitive diagnosis for this patient?
A.Nocturnal oximetry
B.Serum TSH level
C.Multiple Sleep Latency Test
D.MRI of the head and neck
E.Polysomnography

Answer 7

answer = e

polysomnography

underlying co morbidity and postiive sleepiness –> high pre test probability

Question 8

Sleep apnea assoc with?

Answer 8

1) obesity
2) CV disease
3) MVC

Question 9

Consider what questions for sleep in patient?

Answer 9

• Is the patient overweight or obese?
• Is the patient retrognathic?

Does the patient complain of daytime sleepiness?

• Does the patient snore?
• Does the patient have hypertension?

Question 10

Assess which patients for OSA symptoms?

Answer 10

• Morbidly obese- BMI >35
• CHF
• Atrial fibrillation
• Treatment refractory hypertension
• Type 2 diabetes
• Nocturnal dysrhythmias
• CVA
• Pulmonary hypertension
• High-risk driving populations
• Preoperative for bariatric surgery

Question 11

Demographics of OSA
1) gender

2) age
3) race
4) PMH
5) FHx
6) SHx
7) meds

Answer 11

1) male more
2) prevalence incr until 60’s and 70’s
3) minorities
4) chronic rhinitis, acromegaly, neuromuscular disorder, amyloidosis, down
5) 1st degree relative with OSA
6) smoking, etoh abuse
7) sedative-hypnotics, opioids

Question 12

Features of sleep apnea

Answer 12

• Morning headaches
• Nonrestorative or unrefreshing sleep or naps
• “Restless” sleep with frequent movements
• Awakenings with a sensation of gasping or choking
• Excessive body movements during sleep
• Snoring
• Witnessed apneas, gasping, or choking
• Daytime sleepiness or fatigue
• Decline in performance at work or school
• Attention deficit (in children)
• Hyperactivity (in children)
• Impaired cognition (memory and concentration)
• Impotence or diminished libido Insomnia
• Nocturia or enuresis

Question 13

Physical exam

Mallampati

Answer 13

more crowding in posterior pharynx had incr risk during intubation

class 3 and class 4 are also incr risk of OSA

Question 14

Polysomnography

full night (diagnostic or therapeutic)

split night ( (diagnostic or therapeutic))

portable study ( (diagnostic or therapeutic))

when do you use portable study?

Answer 14

full night = diagnostic purpose only

split night = diagnostic (1/2 night) + therapeutic (1/2 night with CPAP) only

portable = diagnostic

high pre-test probability and no cardiopulm comorbidities

Question 15

•Which of the following surgical procedures is most likely to be definitively successful for the treatment of severe obstructive sleep apnea syndrome (OSAS) in an adult patient?
A.Uvulopalatopharyngoplasty
B.Tonsillectomy and adenoidectomy
C.Maxillomandibular advancement
D.Tracheostomy
●

Answer 15

answer = D

Question 16

Treatment of OSA

Answer 16

1) avoid sedatives, stop smoking (because incr inflamm of oropharynx and narrow arirway), treat underlying
2) weight reduction
3) position therapy, O2, pharmaco, positive airway
4) upper airway surgery
5) nerve stim

Question 17

Describe CPAP

Describe bi-level positive airway pressure

describe autotitrating positive airway pressure

describe nocturrnal noninvasive positive pressure ventilation

Answer 17

constant pressure throughout resp cycle

2 pressure levels - high during inspiration, lower during expiration (helps ventilation; if not only obstruction but also ventilation)

looks at breath to breath and augments pressure to ventilate well

ventilator for central or complex or mixed sleep apnea

Question 18

oral appliances for OSA

tongue retainer

when to use?

Answer 18

holds tongue forward

preferred for edentulous patients or those with no dentition

Question 19

oral appliances for OSA

mandibular repositioner

don’t use if (2)

Answer 19

advance mandible forward

1) don’t use if inadeq or broken teeth
2) don’t use if significant TMJ dysfunction

Question 20

surgical options for OSA

tracheostomy

used for?

Answer 20

tracheostomy

tracheal opening distal to pharynx to bypass upper airway obstruction

curative for severe sleepiness, cardiac arrhythmia, severe hypoxemia, hypoventilation, cor pulmonale

may still hypoventilate so still need additional ventilation

Question 21

surgical options for OSA

maxillomandibular advancement

goal

Answer 21

maxillomandibular advancement

advance maxilla and mandible

enlarge retrolingual and retropalatal airway

Question 22

surgical options

UPPP

more or less effective than CPAP

good long-term?

Answer 22

UvuloPalatoPharyngoPlasty

excision of uvula, posterior soft palate, tonsils

less effective than CPAP

recurrence of snoring or OSA after initial benefit

Question 23

Surgical options for OSA
tonsillectomy and adenoidectomy

Answer 23

remove tonsils/adenoids

effective in children with OSA

Question 24

nerve stimulation for OSA

Answer 24

for mild OSA not want CPAP

implanted into skin and insert into genioglossus and intercostal muscle so when do respiratory effort, sends signal to genioglossus to contract and move it out of oropharynx

Question 25

Most common cause of OSA is ____

Related to this is:

Answer 25

periodic collapse of pharyngeal soft tissue during sleep

1) obesity
2) anatomically small pharyngeal airway
3) loss of tone of pharyngeal or genioglossus
4) unstable respiratory control system
5) low arousal threshold
6) changes in lung volume/loss of coordination of airway

Question 26

Patients with OSA have a reduced ____ due to XS soft tissue (fat) or a higly compliant airway

Answer 26

upper airway

Question 27

Patients with OSA have a reduced upper airway due to (2)

Answer 27

1) XS soft tissue (fat)
2) highly complaint airway

Question 28

What can result in partial or complete upper airway collapse in OSA

Answer 28

1) reduced airway size
2) diminished neural input to upper airway muscles

Question 29

What determines the tendency of upper airway to collapse?

Answer 29

Critical closing pressure (Pcrit)

Question 30

Apneas occur when ___ is less than the threshold for inspiratory muscle activation to maintain upper airway patency during sleep

If an overshoot in ventilation decr CO2, what happens to respiratory drive

Thus, the next apnea results from ___

Answer 30

respiratory drive

fall below the threhsold for inspiration to occur

overcompensation for prior apnea

Question 31

Apneas occur when respiratory drive is less than ___

Answer 31

threshold for inspiratory muscle activation and maintaining airway patency during sleep

Question 32

Prevalence of apnea

what % of adults at risk for apnea

if the prevalence is defined as an apnea hypopnea index >5 events per hour (asymptomatic)

if the prevalence is defined as an apnea hypopnea index >5 events per hour + at least one symptom known to respond to treatment (daytime sleepiness)

Answer 32

26%

20%

2-9%

therefore, common to be asymptomatic

Question 33

how does OSA prevalence change with age and gender and race

Answer 33

incr from 18-45 then plateaus at 55-65

more common in african americans < 35 compared to whites and common in Asians

males more than women due to higher apnea hypopnea during adulthood (little difference beyond 60’s)

Question 34

if a patient says that they are feeling sleepy or falling asleep in boring or passive situations, this could imply ___

Answer 34

daytime sleepiness

Question 35

if a patient snores 9common in OSA), what else could they also likely have?

Answer 35

excessive daytime sleepiness

Question 36

what are common symptoms in OSA?

Answer 36

1) XS daytime sleepiness
2) restless sleep
3) silence, then loud snoring
4) poor concentration
5) waking up gasping, choking

Question 37

each apnea event results in arterial ___ and ___

Answer 37

hypoxemia and hypercarbia d

Question 38

what do arterial hypoxemia and hypercapnia in OSA cause?

Answer 38

1) sympathetic hyperexcitation
2) incr peripheral vascular resistance
3) TRANSIENT SYSTEMIC HYPERTENSION
4) precapillary pulmonary vasoconstriction –> pulmonary hypertension
5) vagal tone via carotid body hypoxic stim –> bradycardia

Question 39

why do patients with OSA have pulm hypertension

Answer 39

due to precapillary pulmonary vasoconstriction

Question 40

what causes the bradycardia that occurs in OSA during an apneic episode

Answer 40

carotid body hypoxic stim (breath holding)

Question 41

what happens when the patient wakes up from an apneic episode?

Answer 41

1) aroused
2) pharyngeal patency
3) hyperventilate
4) blood gas back to normal

Question 42

what are treatment plan for apnea

Answer 42

1) CPAP –> good for sleepiness, cog function
1) lifestyle mod = weight loss, exercise
2) sleep position (cervicomandibular support, pillow)
3) mandibular repositioning and tongue retaining
4) CNS stim
5) surgery

Question 43

what are surgical procedures for OSA

Answer 43

1) oral/oropharyngeal/nasopharyngeal procedures
2) hypopharyngeal procedures
3) airway
4) laryngeal procedures

Question 44

Paradigm of checking for OSA

Answer 44

1) clinical probability of positive test for sleep apnea
2) low neck circumference

–> daytime symptoms = conservatve if none to mild

polysomnography = moderate to severe

3) large neck –> polysomnography

if polysomnography not available use portable monitor

Question 45

what happens to airway during sleep? how does this affect neck muscle motor activity?

Answer 45

when in deep sleep, motor activity of neck decr significantly

Question 46

how does airway resistance change with sleep

Answer 46

1) airway narrowed
2) incr resistance
3) body compensates by incr pull of muscles to open airway
4) chronically incr baseline EMG activity due to incr force

Question 47

how does sitting and standing affect airway size

what happens with OSA

Answer 47

airway size decr with supine due to tongue falling back to neck

in sleep apnea, start with smaller airway and more compromise with supine

Question 48

Describe Zone 3

Answer 48

best situation because pressure in upper airway > lower airway > Pcrit

so airway always open

Question 49

Describe Zone 2

Answer 49

snoring

prssure upper airway > P crit > pressure lower airway

upper still greater than lower so air goes downstream but due to narrowing from P crit, create snoring

Question 50

Describe zone 1

Answer 50

P crit > P upstream > P downstream

obstructive sleep apnea

collapse of the straw in all situations causing incr turbulence and obstructed airflwo