Sleep Apnoea Flashcards
(12 cards)
What is obstructive sleep apnoea?
Upper airway narrowing provoked by sleep, causing sleep fragmentation -> daytime symptoms
Whats the typical OSA patient?
Male
Upper body obesity
Undersized or set back mandible
What are some causes of small pharyngeal size?
-Fatty infiltration of pharyngeal tissues and external pressure from increased neck fat or muscle
-large tonsils
-craniofacial abnormalities
-extra sub mucosal tissue
What’s the pathophysiology of OSA?
Upper airway patency depends on dilator muscles - these relax during sleep (so some narrowing normal)
Excessive narrowing due to either already small pharyngeal size
OR excessive narrowing occurring w/ relaxation during sleep
What are some causes of excessive narrowing of airway during sleep?
Obesity - enhance residual muscle dilator action
Neuromuscular disease w/ pharyngeal involvement - loss of dilator muscle tone
Muscle relaxants - sedatives, alcohol
Increasing age
What tool can be used to measure sleepiness?
Epworth Sleepiness Scale:
0=never dose, 1=slight chance, 2=moderate chance, 3=high chance
-sitting and reading
-watching TV
-sitting in public place
-passenger in car for an hour
-lying down to rest in afternoon
-sitting and talking
-sitting quietly after lunch without alcohol
-in a car, while stopped in traffic
What are some clinical effects of OSA?
Excessive daytime sleepiness (epworth sleepiness scale >9)
Nocturia
Rise in BP with each arousal
Recurrent arousals - snoring and apnoea attacks
Repetitive upper airway collapse - arousal req to reactivate dilator muscles. Associated hypoxia and hypercapnia
How is OSA diagnosed?
Sleep studies:
-overnight oximetry
-limited sleep study - oximetry, snoring, body movement, HR, oronasal flow, chest/abdominal movements, leg movements
-full polysomnography - limited study + EEG and EMG
What are some management options for OSA?
-weight loss
-reduce alcohol intake on evenings
-nasal CPAP
-v rarely tracheostomy or gastroplasty/bypass
What is cpap?
Continuous positive airway pressure
-nasal or mouth/nose mask
-upper airway opened with 10cm h20 pressure, prevents airway collapse
What advice is given around driving for someone with OSA?
-dont sleep when sleepy, stop and have a nap
-DVLA must be informed about diagnosis
-may need to stop driving completely
What’s the difference between CPAP and BIPAP
CPAP supplies constant +ve pressure during inspiration and expiration- NOT a form of ventilatory support
BIPAP (NIV) DOES provide ventilatory support as there’s two levels of +ve pressure, for insp and expiration
