Obstructive sleep apnoea

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  2. 2. WHAT IS OSA..? Sleep disorder characterized by recurrent episodes of apnoea / hypopnoea due to narrowing or collapse of upper respiratory tract during sleep despite ongoing breathing efforts .
  3. 3. OSA PREVALENCE.. TABLE 1. STUDIES ON THE PREVALENCE OF OBSTRUCTIVE SLEEP APNEA First Author (Reference) Prevalence Country N ethnicity Diagnostic method Men Women United States Young (7) 602 White Polysomnography 4.0% 2.0% Bixler (9) 1,741 White Polysomnography 3.9% 1.2% Australia Bearpark (10) 485 White MESAM IV* 3.1% India Udwadia (15) 250 Indian Polysomnography 7.5% 4.5% China Ip (12) 258 Chinese Polysomnography 4.1% Ip (13) Chinese Polysomnography 2.1% Korea Kim (14) 457 Korean Polysomnography 4.5% 2.3%
  5. 5. OBESITY Single most important risk factor 1 SD increase of BMI assoc. with 3 fold increase risk of of OSA (Wisconsin sleep cohort) GENETICS Family aggregation of OSA (Cleveland family study) 40 % of genetic polymorphism in OSA is common with obesity but 60 % is independent of obesity (S.R.Patel et al Int. Journ. Of obesity 2008) Candidate genes ApoE4 , Leptin
  6. 6. UPPER AIRWAY ABNORMALITIES Congenital syndromes Retroposed mandible Nasal obstruction ENDOCRINE FACTORS Hypothyroidism 1 , acromegaly 1 associated with increased risk . Female sex hormones are protective 2 1 . J Clin Endocrinol Metab 95: 483495, 2010) 2. Young T, Finn L, Austin D, et al: Menopausal status and sleep-disordered breathing in the Wisconsin Sleep Cohort Study. Am J Respir Crit Care Med 2003; 167:1181-1185
  7. 7. PATHOGENESIS OF OSA.. Upper airway size Upper airway collapsibility Neural component Muscle factors Fluid shift PATHOGENE -SIS OF OSA
  8. 8. AIRWAY SIZE...
  10. 10. NEURAL FACTORS Decreased motor neural output to upper airway dilators 1 Decreased airway reflexes 1.Horner RL: Respiratory motor activity: Influence of neuromodulators and implications for sleep disordered breathing. Can J Physiol Pharmacol 2007; 85:155-165
  11. 11. MUSCLE FACTORS Progressive damage of upper airway dilators (Friberg et al)1 Increased inflammatory markers in muscle cells .2 FLUID SHIFT Increased fluid shift from lower extremities to upper part of body during sleep .3 1. Friberg D, Gazelius B, Hokfelt T, et al: Abnormal afferent nerve endings in the soft palatal mucosa of sleep apnoics and habitual snorers. Regul Pept 1997; 71:29-36. 2.Boyd JH, Petrof BJ, Hamid Q, et al: Upper airway muscle inflammation and denervation changes in obstructive sleep apnea. Am J Respir Crit Care Med 2004; 170:541-546. 3.Redolfi S, Yumino D, Ruttanaumpawan P, et al: Relationship between overnight rostral fluid shift and obstructive sleep apnea in nonobese men. Am J Respir Crit Care Med 2009; 179:241-246.
  12. 12. NOCTURNAL SYMPTOMS : Loud disruptive snoring Apneic episodes Frequent awakening Gasping , choking , bruxism Nocturia Restless sleep
  13. 13. DAY TIME SYMPTOMS Morning headaches Excessive daytime somnolence Fatigue Sleepiness during driving Cognitive decline , inattention Depression with personality changes
  14. 14. Two major mechanisms are important for the patho-physiologic consequences of OSA:- Sleep fragmentation disturbed continuity with deprivation of deep sleep Repeated cycles of de-oxygenation / re- oxygenation Paradigm idea that OSA is an oxidative stress disorder .1 Elevation of inflammatory markers and activation of pathways akin to that in obesity 1 . Lavie et al (Sleep Med Rev 2003; 7:35-51. )
  16. 16. OSA AND INSULIN RESISTANCE.. OSA is an independent risk factor for insulin resistance .1 High incidence of OSA in type II DM -86 % have at least mild OSA and upto 30 % have severe OSA . 2 1.Ip MS, Lam B, Ng MM, et al: Obstructive sleep apnea is independently associated with insulin resistance. Am J Respir Crit Care Med 2002; 165:670-676 2. Foster GD, Sanders MH, Millman R, et al: Obstructive sleep apnea among obese patients with type 2 diabetes. Diabetes Care 2009; 32:1017-1019.
  17. 17. OSA AND CARDIOVASCULAR DISEASES HYPERTENSION Independent association with hypertension after adjusting for obesity . 1 Conversely OSA is common in hypertension . 2 OSA makes individuals more resistant to anti hypertensive therapy . 1.The Lancet, Volume 373, Issue 9657, Pages 82 - 93, 3 January 2009 2. DL Cohen, RR Townsend - Journal of Clinical Hypertension, 2013 3.Logan AG, Tkacova R, Perlikowski SM, et al: Refractory hypertension and sleep apnoea: Effect of CPAP on blood pressure and baroreflex. Eur Respir J 2003; 21:241-247
  18. 18. CARDIOVASCULAR EVENTS Pro-inflammatory and oxidative stress state of OSA leads is related to accelerated atherosclerosis . 1 OSA is associated with a variety of stroke risk factors that may independently contribute to stroke risk. 2 OSA also associated with AF and heart block . 3 1.Savransky V, Nanayakkara A, Li J, et al: Chronic intermittent hypoxia induces atherosclerosis. Am J Respir Crit Care Med 2007; 175:1290-1297 2.Obstructive Sleep Apnea as a Risk Factor for Stroke and Death - H. Klar Yaggi et al N Engl J Med 2005;353:2034- 41. 3. Mehra R, Benjamin EJ, Shahar E, et al: Association of nocturnal arrhythmias with sleep-disordered breathing: The Sleep Heart Health Study. Am J Respir Crit Care Med 2006; 173:910-916.
  19. 19. Patient comes to clinical horizon with Nocturnal symptoms related by the partner Day time symptoms which affects quality of life The other spectrum of patients in whom OSA might be considered Hypertension esp. resistant hypertension 1 Metabolic syndrome Poorly controlled DM AMI / CVA 1.Ruttanaumpawan et al: Association between refractory hypertension and obstructive sleep apnea. J Hypertens 2009; 27:1439-1445
  20. 20. SCREENING FOR OSA.. A few peer reviewed questionnaires have been devised for initial screening The Epworth sleepiness score The Berlin questionnaire Multivariable apnoea prediction index (MAP index) Mallampati score for airway assessment
  21. 21. [Study Name/ID pre-filled] Site Name: ________________________ Initials of Completer: ____ ____ ____ Subject ID: ________________________ Date Form Completed: ___ ___ / ___ ___ / 2 0 ___ ___ Visit Type: ______________________ m m d d y y y y MAP SLEEP SYMPTOM-FREQUENCY QUESTIONAIRE During the last month, on how many nights or days per week have you had or been told you had the following (please check only one box per question): (0) Never (1) Rarely (less than once a week) (2) Sometimes (1-2 times per week) (3) Frequently (3-4 times per week) (4) Always (5-7 times per week) (.) Do not know 1. Loud snoring 2. Your legs feel jumpy or jerk 3. Difficulty falling asleep 4. Frequent wakenings 5. Snorting or gasping 6. Falling asleep when at work 7. Frequent tossing, turning, or thrashing 8. Your breathing stops or you choke or struggle for breath 9. Excessive sleepiness 10. Morning headaches 11. Falling asleep while driving 12. Feeling paralyzed, unable to move for short periods when falling asleep or awakening 13. Find yourself in a vivid dreamlike state when falling asleep or awakening even though you know you are awake
  23. 23. The Epworth sleepiness score most apt for assessing daytime sleepiness a score 11 merits further definitive evaluation A high risk categorization in the Berlin Questionnaire was validated by a positive diagnosis with 86% sensitivity and 76% specificity Mallampati scale predictive value varied with grade
  24. 24. ANCILLARY EVALUATION.. Vitals Height , weight , BMI Abdominal fat assessment Neck girth Airway and otolaryngology assessment Cephalo-metric radiography Metabolic parameters Endocrine assessment ECG , ECHO-cardiography
  25. 25. OVERNIGHT POLYSOMNOGRAPHY Full Overnight Polysomnography remains the gold standard for diagnosis and assessment of OSA Parameters :- EEG EOG EMG chin and anterior tibialis Nasal airflow pressure transducer > nasal thermistor Abdominal and chest wall motion sensor O2 Saturation
  27. 27. ASSESSMENT OF THE PARAMETERS.. Recording sleep Monitored with EEG+EMG+EOG EEG 4 leads placed as per 10-20 System EOG placed at lateral canthi EMG chin electromyogram Airflow assessment Sensitive nasal pressure transducers with cannula are preferred over nasal thermistors
  28. 28. Respiratory effort Assessed by respiratory inductance plethsmography or strain gauge technique using piezoelectric crystals . Oesophageal manometry can be used as a proxy for pleural pressure Oximetry
  29. 29. OTHER SETUPS.. Split night studies 2-3 hours of diagnostic monitoring Time for CPAP titration is reduced Unattended sleep studies Are of 3 types (AASM) Type 2 - EOG + EEG + respiratory monitoring Type 3 2 airflow and/or respiratory effort channel with O2 sat Type 4 continuous single or dual bioparameters
  30. 30. RESULT OF POLYSOMNOGRAPHY Identification of Apnoea/Hypopnoea event Identifying Central vs Obstructive apnoea Grading of OSA objectively using the Apnoea Hypopnoea Index (AHI)
  31. 31. IDENTIFICATION OF EVENT Apnoea cessation of breathing lasting 10 seconds or longer Hypopnoea AASM devices 2 scoring systems 1 . Nasal presure excursions 30% of baseline + 4% O2 desat. + 90% of event duration meets amplitude criteria for hyponoea 2 . Nasal presure excursions 50% of baseline + 3% O2 desat. or arousal + 90% of event duration meets amplitude criteria for hyponoea
  32. 32. PSG TRACING OF OSA..