Sleep Apnoea Flashcards
Definition of apnoea
Cessation of airflow for 10+ seconds
Central apnoea
Respiratory control centre - no resp effort
Obstructive sleep apnoea
Collapse of pharyngeal airway during sleep
OSA: 5 or more obstructive apnoeas/hour
Hypopnoea
Decrease in airflow by 50% accompanied by desaturation of 4% arousal from sleep
Risk factors
Male, obese, 43 cm neck circumference, family history, smoking, alcohol, sedative use, craniofacial/pharyngeal abnormalities, sleeping supine
What is it associated with
Increased soft tissue Enlarged tonsils Pharynx - resistance/tone/caliber Abnormal chin Nasal pathology Normal tongue relaxation
Pathology
Sleep -> relaxation of muscles around pharyngeal airway -> collapse/obstruction of airway -> apnoea -> arousal -> muscle tone returns -> resumption of breathing
Clinical features
Snoring, nocturnal choking, restless sleep, dry mouth, headaches, sleepiness, nocturnia
Complications
Cor pulmonale
Secondary respiratory disease
Secondary polycythaemia
Investigation
Epworth sleepiness scale and sleep studies
Nocturnal oximetry
Diagnosis
Apnoeas + hypopnoeas/total sleep (hr)
Mild: 5-14 per hour
Moderate 15-30
Severe 30+
Management
Resolve signs and symptoms Normalise AHI and oxyhaemoglobin sats levels Behaviour change Mandibular advancement devices Surgery Continuous positive airway pressure