OSA, Obesity hypoventilation syndrome, central sleep apnea

Question 1

OHS

Answer 1

PIckwickian syndrome

Question 2

Confirmation of OHS

Answer 2

BMI>30 and arterial blood gass level on RA documenting presence of daytime hypercapnia with an alternate cause of hypoventilation cannot be identified

Question 3

What do you see on lab with OHS?

Answer 3

elevated serum bicarbonate and secondary erythrocytosis which can indicate chronic hypercapnia and chronic hypoxemia

Their A-a gradient should be normal on RA so no pulmonary parenchymal or airway dx unlikely

Question 4

Treatment of OHS

Answer 4

weight reduction, nocturnal positive pressure ventilation and avoidance of sedative medications.

Needs CPAP or BIPAP

Question 5

Clinical features that suggest OSA

Answer 5

resistant HTN, obesity, daytime solmnolence, excessive snoring and neck circumference that is >43 cm or >17 inches and witnessed apneic smells.

Question 6

fatigue, frequent headaches, systemic HTN in the setting of OBESITY suggests

Answer 6

OSA

Question 7

nocturnal cardiac arrhythmias are common in

Answer 7

OSA and triggered by hypoxemia and alterations in autonimic tone caused by apneic breathing patterns.

Can get sinus pauses, bradycardia which are triggered by increases in vagal tone and subsequent rebound sympathetic tone can lead to tachyarrhthymias (non sustained VT or afib)

Question 8

sinus pauses are

Answer 8

defined as pauses >3 seconds

Question 9

how does excessive ETOH worsen OSA?

Answer 9

it worsens OSA by causing relaxing of the pharyngeal musculature. Can cause cardiac arrhythmias via PVC and afib.

Question 10

what are the cardiovascular effects of OSA

Answer 10

systemic HTN and difficult to control HTN
pulmonary HTN
CAD
nocturnal cardiac arrhythmias: bradycardia and asystole, afib, nonsustained VT
heart failure

can see nocturnal angina too.

Question 11

can OSA affect libido and impotence?

Answer 11

yes

Question 12

potential sequelae of OSA

Answer 12

resistant HTN, angina pectoris, cardiac dysrhythmias, pulmonary HTN and cor pulmonale, polycythemia
decreased libido and impotence

Question 13

OSA can predispose pts to having these arrhythmias

Answer 13

A fib, bradyarrhythmias, AV block, sinus pause, asystole, and NSVT, complex ventricular ectomy

Question 14

diagnostic criteria for obesity hypoventilation syndrome

Answer 14

obesity >30
awake daytime hypercapnia PaCO2>45 mmHg
no alternate cause of hypoventilation

Question 15

Work up for obesity hypoventilation syndrome?

Answer 15

ABG on room air (must see hypercapnia and normal A-a gradient)
no intrinsic pulmonary dx on CXR
restrictive pattern on PFTs
normal TSH
polysomnography

Question 16

treatment of obesity hypoventilation syndrome

Answer 16

nocturnal Positive pressure ventilation as 1st line therapy
weight loss
avoidance of sedative medications
respiratory stimulants (acetazolamide as last resort

Question 17

difference between OSA and OHS is

Answer 17

dyspnea and signs and symptoms of cor pulmonale

Question 18

physical exam findings include florid complexion, cyanosis and enlarged neck circumforence and crowded oropharynx with signs of right sided heart failure

Answer 18

OHS. not OSA because OSA won’t have right sided heart failure symptoms

Question 19

which medications to avoid for OSA or OHS?

Answer 19

no excessive ETOH, sedative hyponotics, narcotics

Question 20

manifestations of OSA

Answer 20

insomnia, non restorative sleep daytime somnolence witness apnea and snoring mood changes, cognitive deficits, impaired concentration fatigue morning headaches

Question 21

Mild OSA can have

Answer 21

asymptomatic but can have hypertension.

Question 22

Tx of OSA

Answer 22

weight loss and CPAP

can try to avoid ETOH and change sleep position for people who have OSA.

Question 23

potential sequelae of OSA

Answer 23

resistant HTN angina pectoris cardiac dysrhythmias pulmonary HTN and cor pulmonale polycythemia decreased libido and impotence

Question 24

diagnosis of OSA

Answer 24

polysomnography or sleep study

Diagnosis if AHI>15
OR
5-14 if also have sleepiness, waking up gasping, habitual snoring observed by bed partner or signs (HTN, DM2, or CAD)

Question 25

what happens in a sleep study?

Answer 25

sleep study documents number of apnea or hyponea as the episodes per hour of sleep via a Apnea hypopnea index or AHI.

Classification for mild, moderate and severe OSA
mild AHI: 5-15
moderate AHI: 15 to 30
Severe AHI>30

Diagnosis if AHI>15 OR
5-14 if also have sleepiness, waking up gasping, habitual snoring observed by bed partner or signs (HTN, DM2, or CAD)

Question 26

snoring with restless sleep
awakening of sensation of choking, gasping or smothering
morning headaches
excessive daytime sleepiness
fatigue limiting daily activities

Answer 26

OSA symptoms

Question 27

who gets OSA

Answer 27

current smokers, males aged 18-60 yrs and have upper airway abnormalities

Question 28

nocturnal hypoxemia, normal BMI, and advanced heart failure

Answer 28

Central sleep apnea

Question 29

What causes central sleep apnea? (explain pathophysiology)

Answer 29

heart failure leads to increased LV filling pressure and resultant pulmonary congestion. this activates the pulmonary vagal irritant receptors leading to hyperventilation and hypocapnia

This superimposed arousals cause further increases in ventilation and drive PaCO2 below the threshold for ventilation causing central apnea. Apnea persists until PaCO2 rises above threshold to stimulate ventilation

central respiratory centers rely on certain amount of PaCO2 to activate breathing

Question 30

Central Sleep Apnea will have THIS form of breathing pattern:

Answer 30

Cheyne Stokes breathing- cresendo decrescendo osillation of tidal volume and intervals of hyperventilation separated by periods of hyponea and apnea.

Question 31

best way to diagnose central sleep apena?

Answer 31

polysomnography - look for Cheyne stokes breathing

Question 32

best way to manage central sleep apnea?

Answer 32

management of heart failure

positive airway pressure therapy and supplemental oxygen