Obstructive Sleep Apnea

Question 1

What percentage of patients with OSA are undiagnosed?

Answer 1

80-95%

Question 2

What are the major risk factors for OSA?

Answer 2

Male
Middle Age
Obesity (BMI >30)
Alcohol consumption
Drug-induced sleep

Question 3

What are the two major factors that cause sleep apnea?

Answer 3

Mechanical obstruction of upper airways
Loss of respiratory drive
BOTH

Question 4

What does a sleep apnea cycle look like?

Answer 4

Oxygen desaturation
sympathetic arousal
Awakening, leading to fragmented sleep

Question 5

What type of sleep is missing when a patient has untreated sleep apnea?

Answer 5

REM sleep

Question 6

What contributes to the loss of tongue tone which leads to an occluded airway?

Answer 6

Genioglossus muscle becomes relaxed

Question 7

What two components contribute to the classification of obstructive sleep apnea?

Answer 7

Cessation of air flow but maintain respiratory effort
Abnormal relaxation of the genioglossus and pharyngeal muscles which cause the tongue to fall backwards obstructing the airway

Question 8

What two components contribute to the classification of central sleep apnea?

Answer 8

Cessation of BOTH air flow and respiratory effort

There is a problem in the ventilatory center of the medulla

Question 9

What two components contribute to the classification of Pickwickian syndrome?

Answer 9

Severe chronich OSA leads to cor pulmonale

Related to morbid obesity

Question 10

What symptoms are associated with Pickwickian syndrome?

Answer 10

Hypersomnolence
Severe hypoxia/hypercarbia
Pulmonary HTN
RV enlargement
Hypervolemia

Question 11

Why do patients with obstructive sleep apnea complain of morning headaches?

Answer 11

Nocturnal CO2 retention and cerebral vasodilation

Question 12

How is the severity of sleep apnea determined?

Answer 12

Number of apneas per hour of sleep

Question 13

How many apneic episodes per hour would be considered mild sleep apnea?

Answer 13

5-15

Question 14

How many apneic episodes per hour would be considered moderate sleep apnea?

Answer 14

15-30

Question 15

How many apneic episodes per hour would be considered severe sleep apnea?

Answer 15

Greater than 30

Question 16

How long does the patient have to stop breathing before it is considered apnea?

Answer 16

Minimum of 10 seconds cessation of breathing

Question 17

What is hypopnea?

Answer 17

Defines by greater than 50% decrease in airflow or oxygen desaturation of greater than 4% for 10seconds or greater

Question 18

What causes arousal of the patient after experiencing apnea?

Answer 18

Either due to the muscle work or the extreme pressure gradient and or hypoxemia

Question 19

How are the respiratory muscles affected by OSA?

Answer 19

Diaphragm and axillary respiratory muscles become completely desynchronized

Question 20

What occurs during the arousal phase of OSA?

Answer 20

Muscle tension is restored and free air exchange is resumed

Question 21

About how many times can this cycle occur in a patient with severe OSA in one night?

Answer 21

300-400 times

Question 22

What is the gold standard for diagnosing sleep apnea?

Answer 22

Polysomnography

Question 23

How does CPAP help in OSA?

Answer 23

Attenuates hemodynamic responses induced by apnea including BP surges and increased SNS activity

Question 24

How is the level of positive pressure required determined for each patient?

Answer 24

Sleep study

Question 25

When would supplemental O2 be required for OSA?

Answer 25

Severe arterial oxygen desaturation

Question 26

What is the name of the procedure done for OSA that removes the tonsils, part of the soft palate and the uvula?

Answer 26

Uvulopalatopharyngoplasty UPPP (UP3)

Question 27

What is the end goal of the UP3?

Answer 27

To enlarge the airway

Question 28

What is another type of surgery to treat OSA using heat to causing scaring of the tissue?

Answer 28

Diathermy Palatoplasty

Question 29

What is the end goal of a diathermy palatoplasty?

Answer 29

Cause scaring that will contract the tissue and prevent the airway from falling

Question 30

What is a major complaint with both surgeries for OSA?

Answer 30

Pain

Question 31

About how many patients with OSA have HTN?

Answer 31

About 40%

Question 32

How does OSA affect awake patient that are normally normotensive?

Answer 32

Increased sympathetic tone BP variability Decreased HR

Question 33

Why do a lot of obese patient have an elevated aldosterone level?

Answer 33

Indicated RAAS activated from SNS activated by OSA

Question 34

How does OSA affect the body's immune response?

Answer 34

Increases level of pro inflammatory cytokines Activated coagulation factors Increased cholesterol levels

Question 35

What percentage of stoke patients have OSA?

Answer 35

70%

Question 36

What percentage of patients with Afib have OSA?

Answer 36

50%

Question 37

What is the thought behind OSA causing Afib?

Answer 37

Dramatic shifts in cardiac transmural pressures and chamber dimensions caused by forceful ventilatory efforts against an obstructed airway

Question 38

How does OSA affect pregnancy?

Answer 38

May be associated with: Low birth weight HTN and possible pre eclampsia

Question 39

How does pregnancy predispose a female to OSA?

Answer 39

Pregnancy induced changes in the upper airway

Question 40

What gender predominately has OSA?

Answer 40

1/3 Males and half as many females

Question 41

What percentage of people are actually aware they have sleep apnea?

Answer 41

20%

Question 42

What comorbidities have a strong correlation with OSA?

Answer 42

GERD AF HTN

Question 43

What screening tool is best to use based on sensitivity and specificity on patients that may have OSA?

Answer 43

STOP BANG

Question 44

What does the pneumonic STOP BANG stand for?

Answer 44

``` Snoring Tired during day Observed stop breathing Pressure (BP) BMI greater than 35 Age greater than 50 Neck circumference Gender male ```

Question 45

What is considered a high risk patient after the STOP BANG tool has been used?

Answer 45

Yes to three or more

Question 46

What is considered a low risk patient after the STOP BANG tool has been used?

Answer 46

Less than three

Question 47

What are good tools to utilize in order to estimate peri-operative risks in patients with OSA?

Answer 47

History Sleep study Type of surgery the patient is undergoing Questionnaire

Question 48

Why should we avoid preoperative sedatives in patients with OSA?

Answer 48

Very sensitive to CNS depressants: Suffer from sleepiness Elevated SNS tone

Question 49

Why might a patient with OSA be polycythemic?

Answer 49

May result from chronic hypoxia

Question 50

What disease process can develop if OSA left untreated causes frequent periods of apnea and hypercarbia?

Answer 50

Cor Pulmonale

Question 51

What considerations should the anesthetist take prior to intubating a patient with OSA?

Answer 51

The patients are often difficult to mask ventilate and trachea can be more difficult to intubate

Question 52

Why are opioids use limited in patients with OSA?

Answer 52

Opioids take away the arousal characteristic in the cycle

Question 53

How should patients with OSA be extubated?

Answer 53

Awake, communicating and breathing spontaneously with adequate TV and SpO2

Question 54

What factors might be considered prior to extubating a patient with OSA?

Answer 54

``` Ease of mask ventilation East of tracheal intubation Nasal packing (can't use nasal airway) ```

Question 55

What is one way that an anesthetist can extubate a patient with OSA with an insurance policy?

Answer 55

Leave the airway exchanger in until the patient is fully awake and doing well in the PACU

Question 56

What position should the OSA patient be placed in while extubating?

Answer 56

Semi-upright, lateral or prone preferable to supine

Question 57

Why shouldnt we extubate an OSA patient that isn't fully reversed?

Answer 57

Weak diaphragm = weak small airway muscles = obstruction

Question 58

Why should we minimized post operative supplemental O2?

Answer 58

It may be used as their drive to breath if chronically hypoxic

Question 59

How much longer should OSA patient be monitored compared to patients without OSA?

Answer 59

3hrs longer