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CVPR: Pulmonary > Sleep Disordered Breathing > Flashcards

Flashcards in Sleep Disordered Breathing Deck (7)
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Definition + primary signs/symptoms of sleep apnea

Hypersomnolent, snoring, males, daytime sleepiness, polycythemia ← Signs/Symptoms

Definition: > 5 episodes apnea/hr, sleepiness during day


Characteristics of an apnic event

  • Air flow down 

  • PaO2 down 

  • PaCO2 up 

  • Hypoxia, hypercapnea =  induced Pulmonary vaso constriction (pulmonary hypertension) + sympathetic nerve firing - constricting peripheral vasculature (systemic hypertension). 

  • Apnic event must be 10 seconds. Can be up to 60 seconds. 


Epidemiology of apnea

  • apnea w/>5 episodes/hour ==> @ 25% of adult men and 9% of adult women
  • many are asymptomatic ==> increased apnea frequency ==> increased symptoms
  • obseity directly associated with severity and onset of obstructive sleep apnea


Pathophysiology of obstructive apnea

  • hallmark = pharyngeal occlusion during sleep
  • lipid accumulation @ soft tissue of the pharynx ==> upper airway narrowing
    • during wakefulness, high levels of electromyographic tone activates pharyngeal dilator muscles and maintains patency
    • During sleep, electromyographic tone is lost ==> predisposingupper airway collapse
  • Facial anatomy appears to be pivotal in the development of sleep apnea.


Apnic event impact on blood gases

  • arterial hypoxemia and hypercapnia ==> sympathetic hyperexcitation + CV changes
  • Peripheral vascular resistance increases during an apnea ==> transient systemic hypertension
  • arterial hypoxemia causes precapillary pulmonary vasoconstriction and its accompanying pulmonary hypertension.
  • Vagal tone (via cartoid body hypoxic stimulation) also increases during an apnea (breath holding) resulting in bradycardia 


Clinical features/complications of OSA

  • systemic hypertension (during wakefulness)
    • often normal blood gases
  • may present w/ CHF or cor pulmonale
  • increased risk for: cerebral vascular accidents, CHF, CAD


Therapeutic approach to apnea

  • maintenance of pharyngeal patency during sleep
  • weight loss
  • continous positive airway pressure (CPAP) = mask device worn during sleep ==> delivers positive pressure into nasal/oral pharynx