Obstructive Sleep Apnea

1. Obstructive Sleep Apnea Cory M. Furse, MD, MPH

2. Disclosure • Multiple photographs used in this presentation have been obtained from GOOGLE. • I have no financial relationships to disclose. • I will be referring to most researchers by first name and/or nickname as if I actually know them.

3. Objectives • Review the pathophysiology of obstructive sleep apnea • Review current recommendations concerning the patient with obstructive sleep apnea for outpatient surgery

4. Normal State • Alae nasi • Tensor palatini • Genioglossis • Geniohyoid • Thyrohyoid • Sternohyoid Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008

5. Polysomnography Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008 Electroencephalogram Electrooculogram Electromyogram of respiratory muscles Airflow at the nose or mouth via thermistor End-tidal CO2 Impedance plethysmography for chest/abdomen movement EKG, NIBP, and SpO2

6. Polysomnography Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008

7. Sleep Apnea Event Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008

8. Symptoms of OSA Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008 Loud snoring

9. Sleep Apnea Event • Altered body position • Decreased pharyngeal muscle tone • Respiratory drive depression - MV  16% - SPO2 2% - PaCO2 4-6mmHg • Depression of protective respiratory reflexes during normal Non-REM sleep Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008

10. Definitions OSA: • 15 or more apneas/hypopneas per hour during sleep, caused by collapse of the upper airway Apnea: • 10s or more without airflow Hypopnea: • 50% reduction in thoracoabdominal movement lasting for 10s Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008

11. Epidemiology Chung – Toronto Western Hospital Curr Opin Anaesthesiol 22:405–411 ~24% of middle-aged men ~9% of middle-aged women ~5% of 3-5yr old children Prevalence of OSA increases with age and body weight An estimated 85% of people with OSA are undiagnosed!

12. Lanphier EH – SUNY at Buffalo J Appl Physiol 18: 471-477, 1963

13. Lanphier EH – SUNY at Buffalo J Appl Physiol 18: 471-477, 1963

14. Lanphier EH – SUNY at Buffalo J Appl Physiol 18: 471-477, 1963

15. Lanphier EH – SUNY at Buffalo J Appl Physiol 18: 471-477, 1963

16. Symptoms of OSA Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008 Loud snoring Hypersomnolence Depressed mentation

17. Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008

18. Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008

19. Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008

20. Symptoms of OSA Levitsky – LSU Adv Physiol Educ 32: 196–202, 2008 Loud snoring Hypersomnolence and Depressed mentation • Interference with normal sleep architecture, esp. REM sleep • Increases risk of motor vehicle accidents Morning Headaches • Repeated dialation of cerebral blood vessels

21. Somers – Iowa J. Clin. Invest. 1995. 96:1897-1904.

22. Signs of OSA Caples – Mayo Clinic Ann Intern Med. 2005;142:187-197. Systemic hypertension • Chronic recurrent sympathetic stimulation • Increase in endothelin, a potent, long lasting vasoconstrictor Heart failure • Right heart 2° to pulmonary HTN • Left heart 2° to systemic HTN Arrhythmias • Atrial fibrillation

23. Signs of OSA Caples – Mayo Clinic Ann Intern Med. 2005;142:187-197. Polycythemia • Chronic hypoxic episodes stimulate renal release of renin • Increase in blood viscosity further exacerbating heart failure if present Metabolic alkalosis • Respiratory acidosis while asleep with renal retention of bicarbonate ions and excretion of H+

24. Obstructive Sleep Apnea Signs Symptoms Loud Snoring Hypersomnolence Depressed Mentation Morning Headaches Nocturia • Systemic HTN • Heart Failure • Arrhythmias • Polycythemia • Metabolic Alkalosis

25. Why do we care? • Difficult Intubation • If GA is employed • Difficult Sedation • If MAC/Regional is employed • Postoperative Pain Control • May increase the severity of their OSA • Liability? • If a patient with OSA has an adverse event at home

26. Gross – Farmington, CT Anesthesiology 2006; 104:1081–93

28. Gross – Farmington, CT Anesthesiology 2006; 104:1081–93 • Endorsed - American Academy of Sleep Medicine - American Academy of Otorhinolaryngology – Head and Neck Surgery • “Affirmation of Value” - American Academy of Pediatrics

29. Chung – Toronto Western Hospital Curr Opin Anaesthesiol 22:405–411 Identification of Patients with OSA

30. Gross – Farmington, CT Anesthesiology 2006; 104:1081–93 Identification of Perioperative Risk

31. Gross – Farmington, CT Anesthesiology 2006; 104:1081–93 Preoperative Preparation • Recommendations - Initiation of CPAP - Use of mandibular advancement devices - Preoperative weight loss • Prior corrective surgery for OSA - Assume these patients are still at risk, unless they have a normal sleep study • Beware of the difficult airway

32. Liang – MGH Anesthesiology 2008; 108:998–1003

33. Liang – MGH Anesthesiology 2008; 108:998–1003

34. Gross – Farmington, CT Anesthesiology 2006; 104:1081–93 Intraoperative Management • Recommendations • Intraoperative medications should be selected with consideration of the potential for postoperative respiratory compromise • If moderate sedation is used, consider using the patients CPAP or oral appliance • Awake extubation • Extubation and recovery in the lateral, semiupright, or other nonsupine position

35. Gross – Farmington, CT Anesthesiology 2006; 104:1081–93 Postoperative Management • Recommendations • Regional > Neuraxial > Oral Opioids > Parental Opioids • Supplemental O2 until at baseline SPO2 on RA • CPAP when feasible • Nonsupine positions • Continuous monitoring of SPO2 when hospitalized

36. Gross – Farmington, CT Anesthesiology 2006; 104:1081–93 Outpatient Surgery?

37. Gross – Farmington, CT Anesthesiology 2006; 104:1081–93 Discharge Criteria • Recommendations • SPO2 should return to baseline on RA • Patients should be monitored a median of 3hr longer then their non-OSA counterparts • Monitoring should continue for a median of 7hr after last episode of obstruction or hypoxemia while breathing RA in an unstimulating environment

38. Gross – Farmington, CT Anesthesiology 2006; 104:1081–93 Appendix: • A median of 10% of outpatients would need to be inpatients if these guidelines were followed • 73% indicate that sensitivity of the criteria for detecting patients previously undiagnosed with OSA is “about right” • 82% indicate that the scoring system for assessing perioperative risk is “about right”

39. Chung – University of Toronto Anesthesiology 2008; 108:812–21

40. STOP BANG S – Snoring, loudly, heard through a closed door T – Tiredness, during daytime O – Observed, witnessed apneic episodes P – Pressure, hypertension B – BMI, > 35 A – Age, > 50 yr N – Neck Circumference, > 40 cm G – Gender, Male Chung – University of Toronto Anesthesiology 2008; 108:812–21

41. Advantage of STOP-BANG is the markedly decreased amount of time required to administer the questionnaire as compared to ASA guideline checklist Chung – University of Toronto Anesthesiology 2008; 108:822–830 STOP BANG vs. ASA guidelines

42. QUESTIONS?