Keywords

These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Pearls

  • Apnea–Hypopnea Index

  • AHI <5—Normal, Snoring, or Upper Airway Resistance Syndrome (UARS)

  • AHI 5–15—Mild Sleep Apnea

  • AHI 15–30—Moderate Sleep Apnea

  • AHI >30—Severe Sleep Apnea

  • Sleep Syndromes:

  • Snoring

  • Upper airway resistance syndrome: daytime hypersomnolence, normal PSG

  • Obstructive sleep apnea syndrome: daytime hypersomnolence

    • Apnea and hypopnea (AHI >5)

  • Definitions:

  • Apneic event: cessation of ventilation for 10 s or longer leading to an arousal

  • Hypopneic event: a decrease in airflow of 30 % with a 4 % decrease in oxygen saturation or a 50 % decrease in airflow with a 3 % decrease in oxygen saturation

  • Respiratory effort-related arousal (RERA): absence of apnea–hypopnea with a 10 s or more duration of progressive negative esophageal pressure leading to an arousal or microarousal

  • Apnea Index (AI): number of apneas in an hour period

  • Respiratory distress index (RDI): number of apneas, hypopneas, and Rera’s in an hour. No longer used in defining sleep apnea

Sleep Physiology

Normal Sleep:

  • Non-rapid eye movement (NREM), “quiet” sleep stage:

    • Steady, slow heart rate

    • Slow respiratory rate

    • Low blood pressure

  • Rapid eye movement (REM)

    • Bursts of rapid conjugate eye movement

    • Increased autonomic activity

    • Large fluctuations in heart rate, respiratory rate, blood pressure

    • Dreaming

  • Age Distribution

    • Infants and children under age 10

      • Higher percentage of REM sleep and stage 3 NREM sleep

    • >10 Years old adults

      • See Table 9.1

    • > 60 Years old

      • Stage 3 diminished, may no longer be present

  • Sex distribution

    • With aging, women maintain slow-wave sleep longer than men

      Table 9.1 Sleep architecture of young healthy adult
      Full size table

Obstructive Sleep Disorders

Definitions:

  • Apneic event: cessation of ventilation for 10 s or longer leading to an arousal

  • Hypopneic event: a decrease in airflow of 30 % with a 4 % decrease in oxygen saturation or a 50 % decrease in airflow with a 3 % decrease in oxygen saturation

  • Respiratory effort-related arousal (RERA): absence of apnea–hypopnea with a 10 s or more duration of progressive negative esophageal pressure leading to an arousal or microarousal

  • Apnea Index (AI): number of apneas in an hour period

  • Respiratory distress index (RDI): number of apneas, hypopneas, and Rera’s in an hour. No longer used in defining sleep apnea

  • Respiratory effort-related arousal (RERA): absence of apnea–hypopnea with a 10 s or more duration of progressive negative esophageal pressure leading to an arousal or microarousal

  • Patterns of arousal

    • Obstructive: lack of airflow despite ventilatory effort

    • Central: lack of airflow resulting from an absence of ventilatory effort

    • Mixed: usually begins as a central apneic event, ends as an obstructive event

Snoring:

  • An undesirable sound that occurs predominantly during sleep

  • Nonapneic snoring can be associated with arousal or sleep fragmentation

  • Does imply upper airway resistance

Upper Airway Resistance Syndrome:

  • Mild sleep-related upper airway system closure

  • No true apnea or hypopnea events

  • Does lead to arousals, sleep fragmentation, and excessive daytime sleepiness

  • Repetitive alpha EEG arousals with sleep fragmentation

  • 15 or more RERAs per hour

  • More often seen in women, nonobese patients, and young adults

Obstructive Sleep Hypopnea Syndrome:

  • Daytime hypersomnolence

  • Greater than 15 hypopneas per hour

  • No apneas

Obstructive Sleep Apnea Syndrome:

  • Apnea–hypopnea index (AHI) of 5 or more

  • Mild: AHI 5–15

  • Moderate: AHI 15–30

  • Severe: AHI ≥30

Physiology of Upper Airway Obstruction

Multifactorial interaction

  • Collapsible airway

    • Obesity, soft tissue hypertrophy, craniofacial abnormalities, neuromuscular tone

  • Pharyngeal dilator muscle relaxation

    • Reflex pathway from the central nervous system fails to maintain pharyngeal patency

  • Nasal obstruction can worsen OSA

    • Open-mouth breathing when asleep that can increase upper airway collapsibility and decrease dilator muscle efficacy

    • Mouth breathing leads to a backward rotation of the jaw displacing tongue base posteriorly, lowers hyoid, leads to pharyngeal collapse

    • Increased resistance upstream leading to an increased collapse downstream via loss of nasal reflex

Symptoms of OSAS

  • Snoring

  • Witnessed episodes of gasping or choking

  • Frequent movements that disrupt sleep

  • Restless sleep

  • Fatigue

  • Waking feeling tired and unrefreshed regardless of time slept

  • Excessive daytime sleepiness

  • Forgetfulness

  • Irritability

  • Sexual dysfunction

  • Motor vehicle accidents (MVAs)

  • Job-related accidents

  • The degree of daytime sleepiness and its impact on quality of life correlate poorly with the frequency and severity of respiratory events

Consequence of Untreated OSA

Increased mortality

Cardiovascular disease

  • Hypertension

    • Likely related to increased sympathetic tone from hypoxemia and frequent arousals

    • Treatment of OSA improves hypertension

    • Apneic event: decreased cardiac output, increased sympathetic nervous system activation, increased systemic vascular resistance

    • Resolution of apneic episode: increased venous return to the right side of the heart leading to an increased cardiac output against the increased vascular resistance, abrupt increase in blood pressure

    • Multiple cycles, eventual increased sympathetic nervous system activation persists

  • Coronary artery disease

    • Recurrent apneas can cause acute thrombotic events, secondary to an increase in platelet activation, and chronic atherosclerosis

  • Congestive heart failure

    • Increased afterload on an already failing heart leading to reduced cardiac output

    • Release of catecholamines from the apneic event can worsen cardiac function

  • Arrhythmia

    • Bradytachyarrythmia are the most common seen

    • Bradycardia starts at cessation of respiration followed by tachycardia at the resumption of respiration as a result of the increased sympathetic activity from the hypoxia and arousal

    • Supraventricular tachycardia, premature ventricular contractions, changes in QT interval

  • Myocardial infarcts

    • Acute ischemia can occur as a result of a depletion of myocardial oxygen supply during apneic events

  • Stroke

    • Cerebral vascular similar stress as cardiac vasculature

    • Apnea leads to decreased systemic pressure and increase in intracranial pressure leading to a decrease in cerebral perfusion, increasing the chance for an ischemic event

    • Fluctuations in cerebral blood flow, increase in atherosclerotic changes to endothelium, increased risk of thrombotic events

  • Risk for insulin resistance

  • Sudden death

  • Pulmonary hypertension

Neurocognitive difficulties

  • Problems with attention, working memory and executive function

Increased risk of fatal and nonfatal motor vehicle accidents (MVA)

Diagnosis

Common symptoms

  • Loud snoring, restless sleep, daytime hypersomnolence

  • In women: insomnia, heart palpitations, ankle edema

Screening

  • Epworth Sleepiness Scale Score >10

    • 0 = would never doze

    • 1 = slight change of dozing

    • 2 = moderate chance of dozing

    • 3 = high chance of dozing

      Situation

      Chance of dozing (0–3)

      Sitting and reading

      		 

      Watching TV

      		 

      Sitting inactive in a public place

      		 

      As a passenger in a car for an hour without a break

      		 

      Lying down to rest in the afternoon when circumstances permit

      		 

      Sitting and talking to someone

      		 

      Sitting quietly after lunch without alcohol

      		 

      In a car, while stopping for a few minutes in traffic

      		 

Rule out other disorders causing fatigue

Examination

  • BMI, blood pressure, neck circumference

  • Body habitus, size of mandible/maxilla, retrognathia/prognathia, facial character

  • Nasal: size, deformity, valve, septum, turbinates, polyps/masses, adenoids

  • Oral Cavity/Oropharynx: size/position of tongue, elongated palate/uvula, tonsils, Mallampati score/Friedman classification, dentition, crowding of oral pharynx

  • Hypopharynx: size/position of tongue base, lingual tonsillar hypertrophy

  • Larynx: mobility of vocal cords, masses/polyps

  • Neck: size, placement of hyoid, jaw/retrognathia

  • Flexible nasolaryngoscopy: awake, asleep, lying down

    • Müller maneuver: nose pinched close with mouth closed, inhale against closed airway examining retropalatal and retrolingual areas for collapse

  • Drug-induced sleep videoendoscopy

    • Propofol-induced sleep

    • Evaluate degree of obstruction from lateral pharyngeal folds, retropalatal, retrolingual areas

Imaging

  • Cephalometric radiograph

    • Inferiorly displaced hyoid, small posterior airway space, long palate

    • Mandibular plane to hyoid distance <21 mm associated with higher success in patients with mild to moderate OSA undergoing uvulopalatopharyngoplasty (UPPP)

  • CT Scan

    • Poor sensitivity for OSA

  • MRI

    • Also poor sensitivity for OSA but excellent evaluation of soft tissue

  • Fluoroscopy

    • Can improve UPPP selection/outcomes

    • Time intensive, radiation exposure

  • Nocturnal Polysomnography (PSG): Gold Standard

Level 1:

  • Electroencephalogram (EEG)

  • Electro-oculogram (EOG)

  • Submental electromyogram (EMG)

  • Electrocardiogram (ECG)

  • Nasal and oral airflow

  • Thoracoabdominal effort

  • Blood oxygen concentration/Oximetry (SaO2)

  • Body position

  • Snoring

Level 2:

  • Unattended study performed in the patient’s home, limited by lack of technician to perform hookup

  • Same measures as Level 1

Level 3:

  • Unattended, same limitations as Level 2

  • Heart rate

  • Airflow

  • Oximetry

  • May underestimate AHI because does not determine sleep versus wake

Level 4:

  • Unattended

  • 1–2 parameters, including oxygen saturation

Treatment

Medical

  • Conservative/Behavioral Modifications

    • Avoid alcohol, sedatives at bedtime

      • Sedatives can promote deep sleep, make apnea more pronounced, blunt drive to arouse and resume breathing

    • Weight loss

    • Positional therapy: supine position, tongue falls posteriorly enhancing obstruction

    • Bariatric surgery consult for morbidly obese patients

  • CPAP (Continuous positive airway pressure): Gold Standard

    • Pneumatic splint, prevents upper airway collapse, constant intraluminal pressure during inspiration and expiration

    • Moderate to severe OSA

      • Reduces AHI, improved subjective and objective sleep measures, quality of life measures, decreased cardiovascular events, decreased MVAs

    • Complicated by patient adherence

      • Compliance considered at least 4 h per night, 5 days/week

  • BiPAP

    • Separately adjustable lower expiratory and higher inspiratory PAP: tolerated better by some

  • APAP (Autoadjusting PAP)

    • Autotitrate PAP to select an effective level of CPAP to prevent upper airway collapse

    • Pressure changes in response to variations, snoring, impedence

  • Oral Appliances

    • Mild to moderate OSA

    • Mobilizes mandible and base of tongue anteriorly, maintains patency of posterior oropharyngeal airway

    • Complicated by tooth/jaw pain, increase in salivation overnight, dry mouth

    • Cost effective but more effective for milder cases

  • Medications

    • Insufficient evidence. Theory: increase upper airway dilator muscle tone, increase ventilatory drive, increase cholinergic tone during sleep versus a decrease in percent of REM sleep, decreased airway resistance, decreased surface tension in the upper airway

    • Progesterone: respiratory stimulant

    • Acetazolamide: increases hydrogen concentration in blood

    • Theophylline: increases hypoxic ventilatory drive

    • Protryptiline: reduce REM sleep

    • Oxygen therapy

    • Fluticasone: if allergic rhinitis component

    • Montelukast (Leukotriene receptor antagonist): decreased adenoid size in children with mild OSA

    • Modafinil (Central post alpha-adrenergic receptor): promotes alertness, used to treat narcolepsy and idiopathic hypersomnia, adjuvant for patients on CPAP who continue to experience excessive daytime sleepiness

    • Nasal Strips

      • Can decrease snoring, mouth breathing, sleepiness

      • Can improve UPPP selection/outcomes

Surgical: Determined by the site of obstruction

  • Counseling possibility of multiple or staged procedures, possibility of tracheostomy

  • Nasal: can reduce CPAP requirements, rarely cures OSA

    • Septoplasty

    • Turbinate surgery

    • Nasal valve repair

    • Sinus surgery

    • Adenoidectomy

  • Palatal

    • UPPP with or without tonsillectomy

      • Remove uvula, redundant tissue from the soft palate and anterior tonsillar pillars

      • Posterior tonsillar pillars advanced lateral-cephalad direction

      • Enlarge nasopharyngeal airway in anterior to posterior dimension

      • Risk of nasal reflux temporarily, infection, change in speech

    • Transpalatal advancement pharyngoplasty after UPPP if persistent OSA

      • Remove 1 cm of the hard palate, advance the soft palate, secure to tensor aponeurosis

    • Expansion sphincteroplasty

      • Variation of UPPP

    • Uvulopalatal flap

      • Variation of UPPP

      • Advancement flap, suture uvula and distal soft palatal tissue upward onto soft palate

      • If VPI, procedure is reversible

      • Contraindicated in patients with excessively thick palates or uvulas

    • Z-palatoplasty

    • Laser-assisted uvulopalatoplasty (LAUP)

      • Primarily for snoring

      • CO2 laser, 2 vertical cuts in soft palate on either side of uvula, amputate lower two-thirds to three-fourths of the uvula Scar retraction and stiffening of the palate is achieved

    • Cautery-assisted palatal stiffening (CAPSO)

      • Remove mucosa off midline of soft palate, induces scar tissue resulting in stiffer palate

    • Radiofrequency ablation of soft palate

      • Soft palate coagulation necrosis causes scarring and contraction of tissue, shorter stiffer soft palate

      • Office-based procedure, local anesthesia

    • Palate implant

      • Used for snoring

      • 3 to 5 implantable rods inserted into the palate for scar formation

      • Risk of implant extrusion

    • Injection snoreplasty

      • Office-based procedure for snoring

      • Inject sclerosing agent (alcohol, sodium tetradecyl sulfate) into midline of soft palate

  • Tongue Base

    • Partial midline glossectomy

      • CO2 laser, electrocautery, plasma knife, coblation

      • Risk of bleeding from lingual artery, hypoglossal nerve injury, hematoma, abscess, dysphagia, taste disturbance

    • Lingualplasty

    • Lingual tonsillectomy

    • Radiofrequency tongue base ablation

      • Four lesions at circumvallate papilla to reduce tissue volume at the tongue base

  • Hypopharyngeal

    • Genioglossus advancement

      • More anteriorly positioned tongue with increased tension on the genioglossus

      • Rectangular geniotubercle osteotomy with advancement

      • Risk of dental root injury, mandible fracture, hematoma

    • Hyoid myotomy/suspension

      • Hyoid mobilized anteriorly and superiorly via attachment to the mandible or to thyroid cartilage

      • Risk of numbness, infection, seroma, fracture, death

    • Tongue suspension

      • Base of tongue to anterior floor of mouth

    • Maxillomandibular advancement

      • Most effective surgical procedure for OSA

      • Enlarges pharyngeal and hypopharyngeal airway

      • Risk of malocclusion, relapse, nerve paresthesia, nonunion, malunion, temporomandibular joint tenderness, infection

  • Tracheotomy

    • Bypass the site of upper airway obstruction

    • Indications: morbid obesity, arrhythmia with apnea, severe apnea with desaturation, cor pulmonale, no response to dietary modifications or CPAP, chronic alveolar hypoventilation

Postoperative care

  • There is an increased risk of airway compromise from edema, respiratory rate alteration secondary to narcotics, possibility of bleeding and difficulty with intubation

  • Repeat polysomnography at 3–4 months postoperatively

Sleep Disorders

Insomnia

  • Recurrent difficulty with sleep initiation, maintenance, consolidation, or quality causing daytime dysfunction. May include non-restorative sleep or sleep of poor quality

  • Daytime symptoms must include at least one:

    • Fatigue or malaise, cognitive impairment (attention, concentration, or memory), social/vocational difficulty or poor school performance, mood impairment or irritability, daytime sleepiness, reduced motivation or energy, tendency to be accident-prone, headache, muscle tension, gastrointestinal upset, concerns about sleep itself

Sleep-Related Breathing Disorders

  • Central Sleep Apnea Syndromes

    • Primary central sleep apnea

    • Central sleep apnea due to Cheyne-Stokes breathing pattern (increased risk of CHF)

    • Central sleep apnea due to high-altitude periodic breathing

    • Central sleep apnea due to medical condition not Cheyne Stokes

    • Central sleep apnea due to drug or substance

    • Primary sleep apnea of infancy

  • Obstructive Sleep Apnea Syndromes

    • Obstructive sleep apnea, adult

    • Obstructive sleep apnea, pediatric

  • Other Sleep-Related Breathing Disorders

    • Sleep apnea/sleep-related breathing disorder, unspecified

    • Obesity-related hypoventilation

Hypersomnias of Central Origin

  • Subclasses:

    • Narcolepsy

    • Recurrent hypersomnia

    • Klein-Levin syndrome

    • Menstrual-related hypersomnia

    • Idiopathic hypersomnia

    • Behaviorally induced insufficient sleep syndrome

    • Hypersomnia due to medical condition

    • Hypersomnia due to drug or substance

Circadian Rhythm Sleep Disorders

Parasomnias

  • Disorders of Arousal

    • Confusional arousals

    • Sleepwalking

    • Sleep terrors

  • Parasomnias usually associated with REM Sleep

    • REM sleep behavior disorder (including parasomnia overlap disorder and status dissociatus)

    • Recurrent isolated sleep paralysis

    • Nightmare disorder

      • Treatment: reassurance, cognitive-behavioral therapy, pharmacologic intervention

  • Other Parasomnias

    • Sleep-related dissociative disorders

    • Sleep enuresis

    • Sleep-related groaning (catathrenia)

    • Exploding head syndrome

  • Parasomnias Associated with Obstructive Sleep Apnea

    • OSA-induced arousals from REM sleep

    • OSA-induced arousals in NREM sleep

    • OSA-induced cerebral anoxic attacks or nocturnal seizures

    • REM rebound from CPAP use leading to:

      • Confusional arousals

      • Sleepwalking

      • Sleep terrors

Sleep-Related Movement Disorders

  • Subclasses

    • Restless leg syndrome

      • Rule out iron deficiency

    • Periodic limb movement disorder

      • Treatment: clonazepam and dopamine agonist therapy

    • Sleep-related leg cramps

    • Sleep-related bruxism

    • Sleep-related movement disorder, unspecified

    • Sleep-related movement disorder due to drug or substance

    • Sleep-related movement disorder due to medical condition

Isolated Symptoms, Apparently Normal Variants, and Unresolved Issues

  • Subclasses

    • Long sleeper

    • Short sleeper

    • Snoring

    • Sleep talking

    • Sleep starts (hypnic jerks)

    • Benign sleep myoclonus of infancy

    • Hypnagogic foot tremor and alternating leg muscle activation during sleep

    • Propriospinal myoclonus at sleep onset

    • Excessive fragmentary myoclonus