Sleep Flashcards
What is Sleep Apnoea?
Sleep apnoea is characterized by disturbances in airflow during sleep leading to excessive daytime sleepiness and sleep disruption.
Question: How is sleep apnoea quantitatively measured?
Answer: It is measured by the Apnoea/Hypopnoea Index (AHI), which is the number of apnoeic and hypopnoeic events per hour of sleep.
At what AHI level is sleep apnoea generally accepted?
Sleep apnoea is generally accepted if the AHI is greater than 15.
Define Apnoea.
Apnoea is the absence of breathing for at least 10 seconds.
Define Hypopnoea.
Hypopnoea is a significant reduction in the rate or depth of breathing, typically over 50%.
What are the two main classifications of sleep apnoea?
Obstructive (OSA) and Central (CSA).
What are the risk factors associated with Obstructive Sleep Apnoea (OSA)?
Risk factors include male gender, obesity, upper airway abnormalities, and sedative use.
What are the risk factors associated with Central Sleep Apnoea (CSA)?
Risk factors include LV failure and brainstem lesions.
What is Cheyne-Stokes respiration?
It’s a form of CSA characterized by alternating apnoea and hyperpnoea in a crescendo-decrescendo pattern of tidal volume.
Associated with HF as most common cause.
What secondary effects of OSA are due to hypoxaemia/hypercapnia?
They include morning headache, polycythaemia, pulmonary/systemic hypertension, and conditions like cor pulmonale/CHF.
What diagnostic procedure is used to evaluate sleep disorders like sleep apnoea?
Polysomnography, also known as a sleep study, evaluates sleep stages, airflow, ribcage movement, ECG, EOG, SaO2, and limb movements.
When is a sleep study (polysomnography) indicated?
It is indicated if there is excessive daytime sleepiness, unexplained pulmonary HTN/polycythaemia, or daytime hypercapnia.
What are some modifiable factors that can be addressed in the treatment of sleep apnoea?
Modifiable factors include weight loss, reducing sedative use, and treating underlying medical conditions.
What are some treatment options for Obstructive Sleep Apnoea (OSA)?
They include nasal CPAP, postural therapy (e.g. avoiding supine sleeping), dental appliances, and surgeries like tonsillectomy or uvula reduction.
What are the treatment options for Central Sleep Apnoea (CSA) or hypoventilation syndromes?
They include nasal BiPAP/CPAP or respiratory stimulants.
