SLEEP APNEA Flashcards
Intermittent cessation of airflow at the nose and mouth for > 10 seconds during sleep.
Sleep apnea
- clinical disorder that arises from recurrent apneas during sleep
- Obstructive sleep apnea/hypopnea syndrome (OSAHS) caused by occlusion of the airway
Sleep apnea syndrome
- caused by absence of respiratory effort
- Mixed sleep apnea: a combination of OSAHS and CSA
Central sleep apnea (CSA)
Prevalence of Sleep Apnea
- 2% of middle-aged women and
* 4% of middle-aged men
Sex Prevalence is twice as high in men as in women.
- Typical patient Male, 30-60 years of age
* Women with OSA are typically postmenopausal
OSAHS Risk Factors
- Obesity In Western populations,
- ~50% of patients have a body mass index (BMI) >30 kg/m2
- Alcohol use
- Structural reduction in airway size
- Shortening of the mandible and/or maxilla (Mandibular retrognathia and micrognathia)
- Endocrine: Hypothyroidism and acromegaly
- Male sex Middle age (40-65 years)
- Smoking & Nasal congestion (possibly)
- Myotonic dystrophy, Ehlers-Danlos syndrome, Down syndrome, Treacher-Collins syndrome
Major causes of OSAHS
- Decreased upper-airway muscle tone
* Decreased upper-airway lumen size
Major causes of CSA
- Defects in the metabolic respiratory control system and/or respiratory neuromuscular apparatus (hypercapnic CSA)
- Primary and secondary central alveolar hypoventilation (Ondine’s curse) syndromes
- Respiratory muscle weakness
SYMPTOMS & SIGNS OSAHS
- Snoring
- Excessive daytime sleepiness
- Sleep attacks
* Result in inability to work effectively
* Damage interpersonal relationships
* Disturbed sleep and unrefreshing nocturnal sleep - Witnessed apneas during sleep
- Depression
- Difficulty concentrating
- Decreased libido
SYMPTOMS & SIGNS CSA
- Poor sleep
- Sleep maintenance insomnia
- Morning headache
- Daytime fatigue and sleepiness
Evidence of:
• Pulmonary hypertension
• Recurrent respiratory failure
• Right-sided heart failure
CSA can be identified with certainty only if either esophageal pressure or respiratory muscle electromyography is recorded and shown to be absent during the events.
A useful guideline for patients with troublesome sleepiness includes those with an ____ >11,and those for whom
sleepiness during work or driving poses problems.
Epworth Sleepiness Score
detailed overnight sleep study that includes recording of:
• Electrographic variables (electroencephalogram, electro-oculogram, and submental electromyogram)
• Ventilatory variables to identify apneas and classify as CSA or OSA
• Arterial oxygen saturation
• Heart rate
• Key finding: episodes of airflow cessation despite evidence of continuing respiratory effort
• Severe OSA: >30 obstructive events and arousals per hour of sleep (or significant daytime sleepiness)
Polysomnography Diagnnosis of OSAHS
• Polysomnography
- Key finding: recurrent apnea not accompanied by respiratory effort
• Measurements of transcutaneous PCO2, which reflect arterial PCO2
- Patients with a defect in respiratory control or neuromuscular function typically demonstrate an elevated PCO2 that tends to increase progressively during the night.
- Patients with instabilities in respiratory control system typically demonstrate a mild degree of hypocapnia.
• Respiratory muscle electromyography: Absent effort with events
DIAGNOSING CSA
TREATMENT APPROACH
DETERMINE WHETHER PATIENT HAS OSAHS OR CSA (EPWORTH SCORE) -> MANAGE OSAHS ACCORDING
TO SEVERITY + Manage CSA by treating the underlying condition.
TREATMENT OF OSAHS
- Prevents upper-airway occlusion by mechanical splinting of the pharyngeal airway with positive pressure maintains airway patency
• Treatment of choice in severe OSA
• Superior to more conservative therapy in mild to moderate disease
• Well tolerated and effective in > 80% of patients who have received proper training
• Improves sleep quality, reduces daytime sleepiness and driving accidents, and decreases nocturnal hypertension
Nasal continuous positive airway pressure (CPAP)
