Luc Sermeus Antwerp University Hospital Belgium

1. Operative risk in patients with Obstructive Sleep Apnea Syndrome (OSAS).Why give preference to RA? Luc Sermeus Antwerp University Hospital Belgium ESRA winterweek 2012

2. OSA: characteristics • Snoring • Apnea caused by airway obstruction • Arousal

3. Anesthesia = a state of unrousable unconsciousness

4. OSA: Preop assessment • OSA already diagnosed • OSA not (yet) diagnosed (80-95%) • 82% men, 93% women • Polysomnography / nocturnal oxymetry / Holter • Cancel surgery?

5. OSAKA- questionary “Half of Chinese anesthesiologists lacked sufficient knowledge and had low confidence levels in dealing with OSA patients” C.L. Wang et al. Sleep Breath 2011, 16 (ahead of print)

6. Preop OSA: symptoms • Snoring • Men 44% > women 28% • 30-60y, peak 50-60y • Obesity (60-90%) BMI > 30kg/m² • BMI: Western > Asian , prevalence OSA similar 5% in men, 2% in women (Young, J Resp Crit Care Med 2002)

7. Preop OSA: symptoms • Snoring • Predisposition • Alcohol, Upper airway infection • Hypertrophic tonsils, nasal obstruction • Craniofacial anatomy (Kushida Laryngoscopy 2000) • Lower facial height, more backward position jaw in Asian population

8. Preop OSA: symptoms Airway obstruction with apnea • Obesity Correlation: fatty tissue lateral of pharynx & OSA Neck Ø > 42-44 cm fast collapse of airway • Micro- / retrognathia • Hypertrophic tonsils, big tongue, position of hyod bone • Maxillar hypoplasia, narrow oropharynx, shape of airway (Ishiguro, Oral Surg Med Path Radiol Endosc 2009)

9. Igor Fajdiga, MD, PhD CHEST August 2005 vol. 128 no. 2 896-901

10. Normal Apneic Igor Fajdiga, MD, PhD CHEST August 2005 vol. 128 no. 2 896-901

11. BMI = 32 Richard J. Schwab et al. American Journal of Respiratory and Critical Care Medicine Vol 168. pp. 522-530, (2003)

12. Preop OSA: symptoms Arousal • O2↓, CO2↑, ventilatory effort↑, stretch-receptors↑  “awake” • Not totally conscious - muscle tone↑- obstruction↓ • Massive sympathetic activation bradycardia tachycardia AHT Cardiac ischemia - CVA

13. OSA: pathophysiology

14. Cardiovascular changes Sympathetic Drive Vasoconstriction Periph. Resistance Heart rate Oxygen demand * LVH * RV dilatation Structural alterations BP Pharyngeal collapse in OSA Intrathoracic Pressure Venous return Afterload Preload *Stroke Volume *LVEF *TD velocities of LV and RV Functional alterations Myocardial OxygenSupply

15. OSA: consequences • AHT: related to severity OSA (risk 10X↑) • Arrhythmia's: nocturnal in 50%, risk2-4X↑ if hypoxemia↑ • Mostly NSVT • Sinus arrest, second degree AV-block, VES, AF • Cardiac ischemia: 14-28% = 5x normal • Heart-failure: 11-37% • Pulmonary HT 20-42%  Right heart-failure

16. OSA: consequences • Hypoxemia  polycythemia • Stroke: 62-77% of stroke has OSA • Severity↑of OSA = Risk↑ of stroke • Terminal renal insuff: 40-60% = f(duration) of OSA • Diabetes • Edema UA • Impaired chemosensitivity

17. OSA: consequences Cardio vascular risk ↑ with severity and duration OSA Overall risk of CVD = x11 = 15-20% fatal complication if severe OSA >10j Risk post therapy = mild OSA = 4-5% Control = ±2% Marin et al. Lancet 2005

18. Preop OSA: premedication • Benzodiazepines: CAVE Muscle tone↓ collapse  apnea  Sat↓ Pulsoxymetry / CPAP • Anti-sialorrhea: Glycopyrrolate • CPAP : to be started, if possible, 2w before surgery

19. OSA + Consequences + Co-pathology = perop / postop risk

20. Perop OSA: anesthetics ALL ANESTHETICS : • Negative effect on cardiac function • Collapsibility↑ • Arousal response↓↓ if O2↓, CO2↑, obstruction • Ventilatory response↓ if O2↓, CO2↑ • UA reflexes↓

21. Physiology: FRC FRC = O2-reserve if apnea • BMI↑ = FRC↓ + O2-consumption↑ • Supine position = FRC↓ • Anesthesia/sedation = FRC↓  preoxygenation before induction of anesthesia = filling FRC with ±100% O2

24. Perop OSA: UA 21,9% difficult UA if OSA ↔ normal 2,6% • 5% failed intubation (=100x normal) Savva D.1994 Br J Anaesthesia 73(2):149-53 66% with a difficult intubation had OSA Chung F et al. 2008 Anesth Analg 107(3):915-20

25. Perop OSA: UA • Difficult Upper Airway • Experienced anesthetist Inadequate face mask ventilation Difficult ( > 2 attempts) intubation • Predictive factors • Complications • Dental injury / UA trauma • Severe hypoxia cerebral ischemia + laryngoscopy asystole

26. OSA: prediction difficult UA • Anatomical factors • Craniofacial morphology / trauma / surgery • Cervical mobility / mouth opening • Micro- / retrognathia / macroglossia • Long soft palate • Mallampati

27. Mallampati Mallampati 3-4 + OSA = difficult intubation until proven otherwise

28. Cormack - Lehane

30. Difficult intubation = Difficult extubation!!!

31. OSA: Difficult extubation Causes • Anatomy • Residual sedation • Instrumentation UAW during intubation / surgery of UA • Edema • Blood • Secretions • Nasal packs

32. OSA: difficult extubation • 5% life threatening postextubation obstruction following surgical treatment of OSA

33. OSA: difficult extubation Pre requisites • Complete recovery of muscle relaxation • Wide awake / communicating • Spontaneous breathing adequate TV oxygenation • Semi sitting position FRC↑

34. OSA: difficult extubation Pre requisites • Stable haemodynamics • CPAP +/- O2 • Re-intubation equipment ready • Perop corticosteroids if necessary • Intensive care / Medium care if necessary

35. OSA: postop complications • Rebound REM ±3th day postop. • Pain↓, surgical stress↓ ±normal sleep pattern • Obstruction, apnea, sympathetic activation • Hemodynamic instability (pt not yet recovered) • Confused / CVA • Disturbed wound healing • Myocardial ischemia / infarction / sudden death • NB: respiratory depression lasts for a week (morphine??)

36. OSA: conclusions • OSA = cause of cardio-vascular complications • OSA = cause of difficult UA • Enough reasons to prefer RA and to convince your patient

37. Literature Obstructive Sleep Apnea, Stroke, and Cardiovascular Diseases Bagai, Kanika MD, MS The Neurologist Issue: Volume 16(6), November 2010, p 329–339