Chapter 30

Disorders of Sleep

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Learning Objectives

Define Obstructive Sleep Apnea (OSA) Explain why airway closure occurs only

during sleep. State the long-term consequences of

uncontrolled OSA. Determine which group of people are at

particular risk of OSA.

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Learning Objectives (cont.)

List the clinical features associated with OSA. Describe how OSA is diagnosed. Describe the treatments available for patients

with OSA. State how continuous positive airway

pressure (CPAP) works.

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Learning Objectives (cont.)

Identify the problems associated with CPAP Describe when bilevel pressure is useful Define “auto-titrating” CPAP Describe the surgical alternatives

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Definitions

Sleep apnea Repeated episodes of no airflow for 10 seconds

Obstructive sleep apnea Effort but no airflow due to upper airway

obstruction Central sleep apnea

CNS fails to signal respiratory effort Overlap syndrome

Chronic obstructive pulmonary disease (COPD) with coexisting OSA

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Definitions (cont.)

Mixed apnea Elements of obstructive & central apnea

Hypopnea Decrease in breathing but still airflow

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Definitions (cont.)

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Definitions (cont.)

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All of the following are types of sleep disorders, except:

A. Obstructive sleep apnea

B. Central sleep apnea

C. Mixed apnea

D. Hyperpnea

Pathophysiology

Obstructive sleep apnea (OSA) Primary cause is small or unstable pharyngeal

airway• Contributing: obesity, tonsillar hypertrophy, small chin• During sleep, upper airway dilator muscles relax,

allowing narrowing or closure in one to many sites OSA increases risk of systemic & pulmonary HTN

• Related to increased sympathetic tone• Right ventricular failure may occur if not corrected

Suspect OSA in obese patients with excessive daytime sleepiness (EDS)

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Pathophysiology (cont.)

Central sleep apnea (CSA) Heterogeneous group of disorders Characterized by periodic breathing

• Waxing & waning of respiratory drive

• Noted by increase then decrease in f & VT

• Cheyne-Stokes respiration Often occur in CHF or stroke Severe type of periodic breathing Pattern of crescendo-decrescendo with hyperpnea

alternating with apnea

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Pathophysiology (cont.)

Overlap syndrome COPD patients with coexisting OSA Patients are typically obese smokers with

moderate to severe nocturnal oxyhemoglobin desaturations

• Worst events occur during REM

Worse prognosis & ABGs, then OSA without COPD

Undiagnosed OSA complicates COPD patients with nightly arousals, dyspnea, desaturations resistant to O2

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All of the following are clinical presentations of CSA except:

A. increase and respiratory rate and Vt after apnea occurs

B. periodic breathing

C. Cheyne–Stokes respirations

D. COPD patient with OSA

Clinical Features

Tend to be men (3:1 ratio men to women), >40 years of age with HTN

Report snoring that has become progressively worse, tied to sensation of choking, gasping, or snorting

Disturbed sleep leads to fatigue, EDS, irritability, depression, possible neuropsychologic deficits

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Clinical Features (cont.)

May have right heart failure secondary to pulmonary HTN More common in overlap syndrome or severe

obesity Increased risk of cardiac arrhythmia

associated with moderate to severe desaturations

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Laboratory Testing

Polysomnogram Overnight study required for definitive diagnosis Record several physiological parameters:

• EEG, EOG, chin EMG, & ECG

• Airflow at nose & mouth

• Ventilatory effort by inductive plethysmography

• Oxygen saturation by pulse oximetry

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Laboratory Testing (cont.)

Interpretation of PSG Effort detected but no airflow, with or without

desaturation, defines OSA Effort detected with minimal airflow, with or without

desaturations, defines hypopnea No effort & no airflow, with or without

desaturations, defines CSA Scoring of PSG

Number of apneas & hypopneas per hour reported as apnea-hypopnea index (AHI)

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Laboratory Testing (cont.)

Severity of OSA defined: Normal: AHI <5 Mild: AHI 5–15 Moderate: AHI 15–30 Severe: AHI >30

Additional information reported Number of arousals/hour (arousal index) Percentage of each sleep stage Frequency of oxygen desaturation, mean SpO2,

lowest SpO2

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Treatment

Behavioral interventions & risk counseling Counsel on risks of uncontrolled sleep apnea Behavioral interventions that may be useful:

• Weight loss if obese

• Avoidance of alcohol, sedatives, & hypnotics

• Avoid sleep deprivation

Positional therapy (avoid supine position) If sleep study notes OSA occurs only supine—avoid Tennis ball at nape of neck will discourage position Typically only useful in mild OSA

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Which of the following is a common feature of OSA patients?

A. approximately 75% of population with OSA are males

B. report snoring which progressively diminishes over time

C. will present with left heart failure secondary to pulmonary HTN

D. will always present with overlap syndrome

Treatment (cont.)

Oral appliances (second-line therapy) Devices that enlarge airway by:

• Moving mandible forward

• Keeping tongue forward

May be useful with mild OSA if cannot tolerate CPAP• Regarded as second-line intervention, particularly for severe

OSA

Fitted by dentists, fairly well tolerated

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Treatment (cont.)

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Treatment (cont.)

Medications Ineffective for most patients with sleep apnea Antidepressants may be useful for mild cases

(rare) Oxygen helps avoid desaturations

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Medical Interventions

● Positive pressure therapy (first-line therapy for OSA)

CPAP of 7.5–12.5 cm H2O alleviates upper airway obstruction in most patients Best titrated during sleep study Shown to:• Decrease EDS & improve neurocognitive testing• Decrease incidence of pulmonary hypertension & right heart

failure• Decrease ventilation-related arousals & nocturnal cardiac

events• Improved daytime oxygenation & ventilation

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Medical Interventions (cont.)

CPAP therapy (cont.) CPAP primarily works by pressure splinting airway

open CPAP titration should stop all apneic episodes &

reduce number of hypopneas Improved sleep occurs with obliteration of

breathing related EEG arousals microarousals Patient compliance is key to CPAP success (80%)

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Medical Interventions (cont.)

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Medical Interventions (cont.)

Bilevel pressure therapy (BiPAP) Better tolerated by patients with high CPAP levels Assists in ventilation & airway splinting

Autotitrating devices (smart CPAP) Adjust to varying patient needs Use computer algorithm to adjust CPAP to

changes in airflow and/or vibration (snoring) Average pressures may decrease

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Medical Interventions (cont.)

Side effects & troubleshooting strategies (PPT) Claustrophobia & skin irritation: change interface Nasal congestion, rhinorrhea, nasal dryness, irritation

• Topical steroids, antihistamines, nasal saline sprays, lotions

Sensation of too much pressure• Ramp-up of pressure over number of minutes MAY be

useful (no evidence)

Pressure leaks• Mouth breathers have problems with nasal masks

• Add chin strap to close mouth or change to full mask (oronasal)

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Which of the following are characteristics of auto-titrating devices (smart CPAP)?

A. Adjust to varying patient needs

B. Use computer algorithm to adjust CPAP to changes in airflow

C. Use computer algorithm to adjust CPAP to changes in vibration (snoring)

D. Average pressures may be increased to 50 cm H2O

Surgical Interventions

Uvulopalatopharyngoplasty (UPPP) Reconstructs portions of uvula, soft palate, soft

tissue of pharynx Success is less than 50% Not currently recommended for management of

OSA Maxillofacial surgery (more promising)

Phase I: UPPP, genioglossal advancement, hyoid bone resuspension

Phase II: Only if phase I is unsuccessful, then advance maxilla & mandible

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Surgical Interventions (cont.)

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Surgical Interventions (cont.)

In worst cases (nonresponsive to all other management techniques), tracheostomy may be performed that bypasses obstruction in OSA

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Role of Respiratory Therapist

Management of patients with sleep disorders Observe evidence of abnormal breathing

during sleep Recommend testing of patients Team member of sleep laboratory Assist in titration of CPAP, interface fitting &

management

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