OSA, Obesity hypoventilation syndrome, central sleep apnea Flashcards
OHS
PIckwickian syndrome
Confirmation of OHS
BMI>30 and arterial blood gass level on RA documenting presence of daytime hypercapnia with an alternate cause of hypoventilation cannot be identified
What do you see on lab with OHS?
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
Treatment of OHS
weight reduction, nocturnal positive pressure ventilation and avoidance of sedative medications.
Needs CPAP or BIPAP
Clinical features that suggest OSA
resistant HTN, obesity, daytime solmnolence, excessive snoring and neck circumference that is >43 cm or >17 inches and witnessed apneic smells.
fatigue, frequent headaches, systemic HTN in the setting of OBESITY suggests
OSA
nocturnal cardiac arrhythmias are common in
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)
sinus pauses are
defined as pauses >3 seconds
how does excessive ETOH worsen OSA?
it worsens OSA by causing relaxing of the pharyngeal musculature. Can cause cardiac arrhythmias via PVC and afib.
what are the cardiovascular effects of OSA
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.
can OSA affect libido and impotence?
yes
potential sequelae of OSA
resistant HTN, angina pectoris, cardiac dysrhythmias, pulmonary HTN and cor pulmonale, polycythemia
decreased libido and impotence
OSA can predispose pts to having these arrhythmias
A fib, bradyarrhythmias, AV block, sinus pause, asystole, and NSVT, complex ventricular ectomy
diagnostic criteria for obesity hypoventilation syndrome
obesity >30
awake daytime hypercapnia PaCO2>45 mmHg
no alternate cause of hypoventilation
Work up for obesity hypoventilation syndrome?
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
treatment of obesity hypoventilation syndrome
nocturnal Positive pressure ventilation as 1st line therapy
weight loss
avoidance of sedative medications
respiratory stimulants (acetazolamide as last resort
difference between OSA and OHS is
dyspnea and signs and symptoms of cor pulmonale
physical exam findings include florid complexion, cyanosis and enlarged neck circumforence and crowded oropharynx with signs of right sided heart failure
OHS. not OSA because OSA won’t have right sided heart failure symptoms
which medications to avoid for OSA or OHS?
no excessive ETOH, sedative hyponotics, narcotics
manifestations of OSA
insomnia, non restorative sleep daytime somnolence witness apnea and snoring mood changes, cognitive deficits, impaired concentration fatigue morning headaches
Mild OSA can have
asymptomatic but can have hypertension.
Tx of OSA
weight loss and CPAP
can try to avoid ETOH and change sleep position for people who have OSA.
potential sequelae of OSA
resistant HTN angina pectoris cardiac dysrhythmias pulmonary HTN and cor pulmonale polycythemia decreased libido and impotence
diagnosis of OSA
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)
what happens in a sleep study?
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)
snoring with restless sleep awakening of sensation of choking, gasping or smothering morning headaches excessive daytime sleepiness fatigue limiting daily activities
OSA symptoms
who gets OSA
current smokers, males aged 18-60 yrs and have upper airway abnormalities
nocturnal hypoxemia, normal BMI, and advanced heart failure
Central sleep apnea
What causes central sleep apnea? (explain pathophysiology)
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
Central Sleep Apnea will have THIS form of breathing pattern:
Cheyne Stokes breathing- cresendo decrescendo osillation of tidal volume and intervals of hyperventilation separated by periods of hyponea and apnea.
best way to diagnose central sleep apena?
polysomnography - look for Cheyne stokes breathing
best way to manage central sleep apnea?
management of heart failure
positive airway pressure therapy and supplemental oxygen
