OSA Flashcards
what is OSA?
obstructive sleep apnoea -a sleep related breathing disorder characterised by recurrent episodes of complete or partial obstruction of the upper airway during sleep.
what actually happens during OSA?
during sleep there are either apnoeas (complete obstruction of the upper airway causing temporary cessation of breathing) or hypoapnoeas (decreased airflow due to partial obstruction)
this can happen 100s of times a night.
why does OSA happen?
tone of tongue, tonsils, and soft palate reduced during sleep-this means they can obstruct airflow at level of pharynx during sleep due to excessive collapsing forces arounf the pharynx that exceed the decreased muscle tone
what are the physiological effects of apnoeas?
-they cause transient oxygen dips which causes subconscious arousal hence why they don’t get refreshing sleep.
-low 02 activates central chemoreceptors to give you a wave of adrenaline which messes with pulse and BP during critical time for CV health regulation (night) causing long term cardiovascular issues
does OSA cause night time hypercapnia?
no
hypercapnia +daytime sleepiness suggests comorbid COPD or obesity hypoventilation syndrome.
what is a hypopnea?
partial obstruction of airway -10s or more duration with 30% or more reduction of flow and desaturation of 4% or more
what are the risk factors for OSA?
obesity -but 25-30% of OSA patients aren’t obese
male sex
craniofacial abnormalities
narrow nasopharynx
what are the symptoms of OSA?
unrefreshing sleep
excessive daytime sleepiness
snoring/irregular breathing/stopping breathing at night -breathing usually normal in day
cycles of transient arousal from sleep
what scale can be used to grade OSA severity?
epworth sleepiness scale
what is the name of a good screening tool for OSA?
stop-bang
what are the investigations for OSA?
investigations when awake are usually normal
polysomnography
what is the management for OSA?
weight loss, wean off opiates and benzo, mandibular advancement devices made by dentists, CPAP
