Chapter 30 Disorders of Sleep

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 2 Objectives  Identify the estimated prevalence of obstructive sleep apnea (OSA) in the general population.  Define OSA, central sleep apnea, combined sleep apnea, and overlap syndrome.  Explain why airway closure occurs only during sleep.  State the possible long-term consequences of uncontrolled OSA.

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 3 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.

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 4 Objectives (cont.)  Identify the problems associated with CPAP in the treatment of OSA.  Describe when bilevel pressure is useful in the treatment of OSA.  Describe “auto-titrating” CPAP in the treatment of OSA.  Describe the surgical alternatives for patients with severe OSA.

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 5 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  Mixed apnea: elements of obstructive and central apnea  Hypopnea: decrease in breathing but still airflow

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 6 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 and 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).

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 7 Pathophysiology (cont.) Central sleep apnea (CSA)  Heterogeneous group of disorders  Characterized by periodic breathing  Waxing and waning of respiratory drive  Noted by an increase then a decrease in f and V T  Cheyne-Stokes respirations Often occur in CHF or stroke Often occur in CHF or stroke Severe type of periodic breathing Severe type of periodic breathing Pattern of crescendo-decrescendo with hyperpnea alternating with apnea Pattern of crescendo-decrescendo with hyperpnea alternating with apnea

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 8 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 and ABGs, then OSA without COPD  Undiagnosed OSA complicates COPD patients with nightly arousals, dyspnea, desaturations resistant to O 2

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 9 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 neuropsychological deficits  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

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 10 Laboratory Testing  Polysomnogram (PSG)  Overnight study required for definitive diagnosis  Record several physiological parameters: EEG, EOG, chin EMG, and ECG EEG, EOG, chin EMG, and ECG Airflow at nose and mouth Airflow at nose and mouth Ventilatory effort by inductive plethysmography Ventilatory effort by inductive plethysmography Oxygen saturation by pulse oximetry Oxygen saturation by pulse oximetry

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 11 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 and no airflow, with or without desaturations, defines CSA  Scoring of PSG  Number of apneas and hypopneas per hour reported as an apnea-hypopnea index (AHI)

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 12 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 SpO 2, lowest SpO 2

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 13 Treatment  Behavioral interventions and risk counseling  Counsel on risks of uncontrolled sleep apnea  Behavioral interventions that may be useful Weight loss if obese Weight loss if obese Avoidance of alcohol, sedatives, and hypnotics Avoidance of alcohol, sedatives, and hypnotics Avoid sleep deprivation 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

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 14 Treatment (cont.) Medical interventions Positive pressure therapy (first-line therapy for OSA) Positive pressure therapy (first-line therapy for OSA) CPAP of 7.5–12.5 cm H 2 O alleviates upper airway obstruction in most patients CPAP of 7.5–12.5 cm H 2 O alleviates upper airway obstruction in most patients  Best titrated during sleep study  Shown to: Decrease EDS and improve neurocognitive testing Decrease EDS and improve neurocognitive testing Decrease incidence of pulmonary hypertension and right- sided heart failure Decrease incidence of pulmonary hypertension and right- sided heart failure Decrease ventilation-related arousals and nocturnal cardiac events Decrease ventilation-related arousals and nocturnal cardiac events Improved daytime oxygenation and ventilation Improved daytime oxygenation and ventilation

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 15 Treatment (cont.)  CPAP therapy (cont.)  CPAP works by pressure splinting the airway open.  CPAP titration should stop all apneic episodes and reduce number of hypopneas.  Improved sleep occurs with obliteration of breathing related EEG arousals and microarousals.  Patient compliance is key to CPAP success (80%).  Bilevel pressure therapy (BiPAP)  Better tolerated by patients with high CPAP levels  Assists in ventilation as well as airway splinting

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 16 Treatment (cont.)  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  Side effects and troubleshooting strategies (PPT)  Claustrophobia and skin irritation: change interface  Nasal congestion, rhinorrhea, nasal dryness, irritation Topical steroids, antihistamines, nasal saline sprays, lotions Topical steroids, antihistamines, nasal saline sprays, lotions

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 17 Treatment (cont.)  Side effects and troubleshooting strategies (cont.)  Sensation of too much pressure Ramp-up of pressure over a number of minutes MAY be useful (no evidence) Ramp-up of pressure over a number of minutes MAY be useful (no evidence)  Pressure leaks Mouth breathers have problems with nasal masks. Mouth breathers have problems with nasal masks. Add a chin strap to close mouth or change to full mask (oronasal). Add a chin strap to close mouth or change to full mask (oronasal).

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 18 Treatment (cont.)  Oral appliances (second-line therapy)  Devices that enlarge airway by: Moving mandible forward Moving mandible forward Keeping the tongue forward Keeping the tongue forward  May be useful with mild OSA if cannot tolerate CPAP  Fitted by dentists, fairly well tolerated  Medications  Ineffective for most patients with sleep apnea  Antidepressants may be useful for mild cases (rare)  Oxygen helps avoid desaturations.

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 19 Treatment (cont.) Surgical interventions  Uvulopalatopharyngoplasty (UPPP)  Reconstructs portions of uvula, soft palate, and 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, and hyoid bone resuspension  Phase II: Only if phase I is unsuccessful, then advance maxilla and mandible

Mosby items and derived items © 2009 by Mosby, Inc., an affiliate of Elsevier Inc. 20 Treatment (cont.) Surgical interventions (cont.)  In worst cases (nonresponsive to all other management techniques), a tracheostomy may be performed that bypasses the obstruction in OSA.