1. Sleep Apnea Syndrome Sung Chul Hwang, M.D. Department of Pulmonary and Critical Care Medicine Ajou University School of Medicine

2. Obstructive Sleep Apnea A disorder characterized by collapse of pharyngeal airway during sleep accompanied by arousal from sleep. In OSA continued ventilatory effort is present. But in Central Sleep Apnea both the ventilatory effort and air flow is absent.

3. Definitions ( 1 ) Apnea : complete cessation of air flow for at least 10 seconds Hypopnea : reduction in air flow of more than 50 % accompanied by desaturation of at least 4% or an arousal from sleep

4. Definitions ( 2 ) Apnea Index : the Average number of apneas per hour of sleep Apnea/hypopnea index(Resp. Disturbance Index) : Number of Apneas + hypopneas per hour of sleep

5. Sleep Apnea Hypopnea Syndrome(SAHS) : patients who have sleep study based diagnosis of sleep apneas and hypopneas associated with the clinical symptoms of the disorder Severe SAHS : > 50 AHI Mild & Moderate SAHS : AHI 10 - 30 Definitions ( 3 )

6. Classifications Cerntral Apnea : No effort to breat Obstructive Apnea : Ventilatoey effort is presebt but no air flow because the Upper airway is closed

7. Epidemiology of OSA 9.1% of men and 4.0 % of women if AHI > 15 is used 3 million men and 1.5 million women with OSA ( AHI > 5 with complaint of day time sleepiness)

8. Pathogenesis Parynx is abormal in size and easy collapsibility in OSA Changes during sleep : Reduced tonic input to upper airway muscles Diminished protective pharyngeal reflexes Reduced load compensation “set point” to increased sensitivity to hypocapnea induced apneic threshold Site of the obst. : anywhere from nose to glottis

10. Clinical Manifestations During SleepBehavioralCardio- respiratory SnoringDaytime sleepiness Nocturnal asphyxia Traffic Accidents 2-3 tines Tachyarryhthmia VT, Bradycardia Repeated Arousal during sleep Intellect change Personality change Impotence Pul.Hypertension RV failure LV failure ] Polycythemia

11. Increased PaCO2 Increased HCO3, Decreased Cl - Clinical Features Decreased pHCentral Vasodilatation Morning Headache Decreased PaO2 Arousal from sleep Day time Somonolence Hb desaturationCyanosis Polycythemia Pulmonary Vasospasm Cor Pulmonale Pul. HiBP

13. Others Nocturnal choking episodes Arousal Insomia/ sleep disruption Nocturia G-E reflux Atypical chest pain Night sweating Decreased libido Concentration and memory defect

14. Physical Examinations Hypertensive Obese Middle aged Large thick neck “ crowded” Upper airway Nasal Obstruction Low hanging palate Retrognathia Micrognathia

15. Diagnosis of OSA History Physical Exam Routine Lab : X-rays, ABG, EKG, CBC Polysomnography Overnight Oxymetry

16. Polysomnography

18. Obstructive Sleep Apnea

19. Treatment (1) General Measures Weight control Stop smoking Alcohol withdrawal Treat coexisting disease Avoid driving motor vehicles

20. Treatment (2) Correct Anatomic Airway obstruction Enlarged tonsils or adenoids Skeletal abnormalities involving craniofacial configurations Nasal obstructions

21. Treatment (3) Nasal CPAP Treatment of choice for OSA Well tolerated in 80 % of patients Nasal masks, nasal Prongs, Oronasal masks

22. CPAP in Obstructive Sleep Apnea

23. Treatment (4) Surgical Procedures Tracheostomy Uvulopalatopharyngoplasty (UPPP) Maxillofscial surgery combined with UPPP Laser Assissted Uvulopalatoplasty(LAUP) Consider in those CPAP is not an option Effective in Snoring but tend to recur

24. Treatment (5) Oral Appliances Mandibular advancement prostheses Improve upper airway patency Hold the tongue foward

26. Mandibular Advancement Splint

28. Maxillofacial Advancement Surgery for OSA

31. Cardiac Ischemia During Apneic Episode

32. Obstructive Sleep Apnea

35. Central Sleep Apneas Sung Chul Hwang, M.D. Dept. of Pulmonary and Critical Care Medicine Ajou University School of Medicine

36. Central Sleep Apneas Central apneas reflect unstable breathing control Decreased resp. drive : Hypoventilation during sleep --> Hypercapneic CSA Increased resp. drive : Hyperventilation during wake and sleep --> Hypocapneic CSA

37. Mechanisms Result of abolished ventilatory motor out- put Hypocapnea during NREM sleep is the major cause of reduced ventilatory motor out put

38. Pathogenesis Instability often occurs at sleep onset : PaCO2 during awake is less than required for rhythm generation in sleep Enhanced by chronic hyperventilation during wakefulness and hypocapnea below threshold Hypoxia, Aggravation of cardiorespiratory disease, Hyperventilation, Pulmonary congestion Circulatory slowing due to cardiac failure lead to ventilatory instability

39. Clinical Features CSA is an alveolar hypoventilation syndrome Daytime hypercapnea and hypoxemia Recurrent resp. failure, polycythemia, Pul. hypertension, Rt. heart Failure Poor sleep, morning headaches, daytime fatigue, somnolence, nocturnal awakenings, etc

40. Diagnosis Clinical features Definitive Dx : Polysomnography Measurement of transcutaneous PaCO2 Defect in Resp. control or NM function : elevated Ps CO2 that tend to increased during night esp. REM sleep

41. Central Sleep Apnea

42. Treatment Nocturnal O2 to correct Hypoxemia Acetazolamide -> Acidosis -> increase ventilation Nasal CPAP : increasePaCO2 as the added expiratory mechanical load Nasal CPAP is particularly effective in CSA secondary to CHF in improving sleep quality and daytime cardiac condition

43. Disoders of Ventilation Sung Chul Hwang, M.D. Dept. of Pulmonary and Critical Care Medicine Ajou University School of Medicine

44. Chemoreceptor Central Medulla Oblongata pH, PaCO2, PaO2 fall in pH of ECF and Carotid body Fine regulation Peripheral Aortic and Carotid body PaO2 dominant during Chronic hypoxia Coarse regulation

45. Alveolar Hypoventilation Increased PACO2 & PaCO2 above normal Impaired respiratory drive: brain stem, carotid body trauma Reduction in over all minute ventilation: resp. muscles, spinal cord, peripheral nerves Impaired respiratory apparatus : chest wall, airways and lung

46. Neuromuscular Disorders Spinal cord, peripheral nerves, respiratory muscle disease orthopnea, paradocxical movement of abdomen and diaphragm Dx : Rapid deterioration of MVV, reduced PImax, PEmax, reduced transdiaphragmatic pressures and response to phrenic nerve stimulations

47. Pathophysiology Increased PACO2 & PaCO2 Respiratpory Acidosis Metabolic compensation -- increase in HCO3 -- Decrease in Cl - Decrease in PAO2 & PaO2 Pulmonary vasoconstriction, Pulmonary hypertension, RV hypertrophy, CHF (Cor pulmonale)

48. Mechanoreceptor Stretch receptor : smooth muscle of trachea and main bronchus Irritant receptor : beneath the epithelium of larynx, trachea, bronchi J- receptor : periphery of lung C- receptor : pulmonary interstitial space near pulmonary and bronchial circulation

49. Clinical features Hypoxemia, cyanosis, polycythemia chronic hypoxemia, hypercapnea, pulmonary HTN, CHF ABG abnormality esp. in sleep and sleep disturbances Sx : morning headache, fatigue, daytime somnolence, mental confusion, intellectual impairment specific features of underlying diseases

50. Diagnosis Defect in Control System : impaired response to chemical stimuli, able to hyperventilate voluntarily Defects in N-M System : Unable to hyperventilate, abnormal static and dynamic lung measurements Defects in Chest wall, Lungs, Airways : normal airway resistance and compliance, widened (A-a) DO2

51. Treatment Treat individual underlying disease Correction of Metabolic Alkalosis O2 supplements Respiratory Stimulants (medroxyprogesterone) Mechanical Ventilation : especially during sleep Diaphragmatic pacing

52. Primary Alveolar Hypoventilation (Ondine’s Curse) Chronic hypoxemia and hypercapnea without identifiable cause defect in metabolic respiratory control 20 - 50 yrs of age males Sx and Signs of alveolar hypoventilation treatment : general supportive care for hypoventilation

53. Obesity-Hypoventilation SD (Pickwickian SD) Massive obesity Reduced FRC Underventilation of Lung base and widening of (A-a)PO2 Chronic hypercapnia, hypoxemia, polycythemia, pulmonary HTN, Right heart failure Sx : OSA, sleep induced hypoventilation Tx : stop smoking, weight reduction, correct OSA, medroxy progesterone

54. “Panda-Eye” Sign “ ” Sign