Sleep Disorders Flashcards
What is Cheyne Stokes respiration?
recurrent central apnoeas/hypopneas alteranting with a respiratory phase exhibiting a crescendo-decrescendo pattern of flow, most commonly caused by CCF or neurological disorder (post stroke)
What is the difference between obstructive and central apnoeas?
obstructive apnoeas have associated respiratory effort whereas central apnoeas lack respiratory effort
What is the diagnostic criteria for OSA?
apnoea/hypopnea index > 5/hr + symptoms
or apnoea/hypopnea index > 15
What is the strongest risk factor for OSA?
increased BMI
What is the increased risk of MVA in OSA?
4x increased risk
What are the complications of OSA?
HTN IHD CCF AF CVA pulmonary HTN DM
What is the most common arrhythmia in OSA?
nocturnal bradyarrhythmias
What are the elements of the STOP BANG score?
snoring tiredness observed apnoeas blood pressure BMI age neck circumference gender
What is the sensitivity and specificity of the Epworth Sleepiness Scale for OSA?
low sensitivity and specificity
What is the best predictor of CPAP usage?
adherence at 2 weeks - 3 months
What are the benefits of CPAP?
improves daytime sleepiness, depression, cognitive function, QOL, systolic BP
reduces risk of MVA
What did the SAVE study show?
No RCT evidence that CPAP decreases CV mortality
What did the RICCADSA study show?
treating moderate to severe OSA in non sleepy patients with CAD did not improve CV outcomes
What are the features of obesity hypoventilation syndrome?
- awake hypercapnea (CO2 > 45)
- BMI > 30
- sleep disordered breathing
How does obesity hypoventilation syndrome usually present?
acute on chronic respiratory failure and/or right heart failure
How is leptin involved in the pathophysiology of OHS?
there is leptin resistance and leptin is a respiratory stimulant
What is the treatment for OHS?
CPAP usually first choice if co-exisiting OSA, but if minimal/mild OSA may need NIV
What is the first line treatment for sleep disordered breathing in heart failure?
optimise heart failure therapy
Does positive airway pressure reduce mortality in heart failure?
No
What are the benefits of CPAP in OSA/heart failure?
improve EF
improve BP
improve exercise capacity
improve QOL
What did the SERVE HF study show?
increased mortality in adaptive servo ventilation for Cheyne Stokes Respiration in heart failure
What causes narcolepsy?
autoimmune destruction of hypothalamic neurones that produce hypocretin (which regulates arousal and transition between wake and sleep)
