Test #2 Sleep Apnea ARTICLES - Rude man

Question 1

Define obstructive sleep apnea.

Answer 1

repetitive partial or complete obstruction of the upper airway and is characterized by episodes of cessation of breathing during sleep lasting for more than 10 seconds

Question 2

What is considered the “gold standard” for diagnosing sleep apnea?

Answer 2

polysomnography (PSG)

aka - a sleep study

Question 3

The apnea hypopnea index (AHI) is the number of episodes of apnea or hypopnea per hour during sleep. What is the accepted minimal AHI for a diagnosis of OSA?

Answer 3

AHI of 10, plus symptoms of excessive daytime sleepiness.

Question 4

List the patient populations at risk for developing OSA. (8)

Answer 4

• men
• obese
• smokers
• diabetics
• treatment resistant HTN
• the acute phase of stroke
• hypothyroidism
• alcoholics

Question 5

Propofol can cause a dose-dependent inhibition of what muscle?

Answer 5

the genioglossus muscle (keeps the tongue anterior), resulting in greater collapsibility of the upper airway

Question 6

Opioids can impair respiratory function by direct action on the respiratory motor activity of what two nerves?

Answer 6

hypoglossal

phrenic

Question 7

Mechanically, when does an upper airway obstruction occur? (vague question…sorry)

Answer 7

when the negative pressure generated by the inspiratory muscles exceeds the capacity of the upper airway dilator muscles to maintain airway patency

Question 8

Investigation of the actions of sedatives, anesthetics, and analgesics points to the ________ as a primary site of obstruction after anesthesia.

Answer 8

pharynx

Question 9

So, the three things that occur with obstructive sleep apnea…

Answer 9

• increased airway collapsibility due to an increase in the critical closing pressure
• loss of tonic activity in pharyngeal muscle
• failure of the phasic activation of upper airway muscles before diaphragmatic activity

Question 10

Post-op complications associated with OSA. (6)

Answer 10

• respiratory complications
• sustained arrhythmias / conduction disturbances
• HTN
• MI
• CHF
• pulmonary edema

Question 11

What are two questionnaire based screening tools for OSA?

Answer 11

The Berlin Questionnaire

STOP-BANG

Question 12

Which screening tool is ideal for pre-op screening?

Answer 12

STOP-BANG

Question 13

What does STOP-BANG stand for? (8)

Answer 13

• do you SNORE loudly
• do you feel TIRED during the daytime
• has anyone OBSERVED that you stop breathing during sleep
• do you have a history of high blood PRESSURE
• BMI > 35
• AGE > 50
• NECK circumference > 40cm
• male GENDER

Question 14

What is the sensitivity of the STOP-BANG questionnaire?

Answer 14

85-100%

Question 15

What are some medications that can be used for post-op pain control that are not opioids and can help prevent airway obstruction?

Answer 15

• NSAIDS
• dexmedetomidine
• acetaminophen

(novel approaches - ketamine, clonidine, or gabapentin)

Question 16

ASA guidelines recommend what patient position for extubation in OSA patients?

Answer 16

semi-upright position

Question 17

Define central sleep apnea.

Answer 17

a temporary failure of the generation of breathing rhythm

(polysomnographically, central sleep apnea is recognized by the absence of naso-oral airflow and by thoracoabdominal excursions that reflect the failure of activation of inspiratory pump muscles)

Question 18

Why does it occur?

Answer 18

it occurs when the level of PCO2 falls below the apneic threshold, a PCO2 below which breathing ceases

(so they breath really fast, blow off a bunch of CO2, then stop breathing so they can build it back up again)

Question 19

Episodes of central sleep apnea associated with periodic breathing can occur in what three instances?

Answer 19

• in severe CHF with systolic dysfunction
• at high altitude
• in an idiopathic form

Question 20

What is the mechanism of action of acetazolamide in relation to central sleep apnea?

Answer 20

its related to metabolic acidosis, which stimulates chemoreceptors.

(so, the medication increases the amount of CO2 and prevents it from getting too low from the rapid breathing)

Question 21

What is a possible therapeutic action of acetazolamide?

Answer 21

it could be because of diuresis and improvement in pulmonary congestion.

(the pulmonary congestion associated with CHF can trigger the lung stretch receptors and cause rapid breathing, which then drops the CO2, and creates central sleep apnea)