Perioperative Management of Patients with Obstructive Sleep Apnea (OSA)

1. Perioperative Management of Patients with ObstructiveSleep Apnea (OSA) Dr. Bertrand Lau Department of Anaesthesia Burnaby Hospital

2. Disclosures • No financial relationships or commercial interests relevant to the content of this talk

3. OSA Overview • Definition: • ≥ 5 apneas/hypopneas per hr • Apnea hypopnea index (AHI): • Mild: 5 – 20 • Moderate: 21 – 40 • Severe: >40 • Prevalence • 4% of men, 2% of women • 24% of those older than 65

4. Why does OSA happen? • Because humans talk!

5. Sleep Disordered Breathing in OSA • Arousal events • Verifiable on EEG • Activates the pharyngeal muscles & • The sympathetic nervous system (SNS) ↓O2 Activate SNS Pharynx Closes Sleep Deepens Arousal SNS activity↓ Opens Pharynx ↑O2

6. Pathophysiology of OSA • Systemic & pulmonary hypertension • CVA • LVH → ischemia → arrhythmias → death • RVH → cor pulmonale • Negative pressure pulmonary edema • GERD • Social problems: Day time sleepiness, nocturnal social isolation

7. Perioperative Respiratory Problems • Anaesthetic: • Impaired respiratory mechanics due to GA • Worsened loss of pharyngeal muscle tone • Decreased respiratory drive due to anaesthetic and analgesic agents • Surgery: • Impaired respiratory mechanics from positioning • Splinting from pain • Direct airway trauma leading to edema

8. Other Perioperative Problems • Surgical stress response, pain, fluid shifts, respiratory complications etc., also lead to: • M.I. • CVA • CHF • Arrhythmias • Post-op delirium

9. Rate of Complications in TJA • Gupta, Parvizi et al. 2001 Mayo Clin Proc • Restrospective, case-control study • Total joint arthroplasties • N=202 • OSA vs. no OSA • Post-op complication rates: 39% vs. 18% • Serious complication rates: 24% vs. 9% • LOS: 6.8 vs. 5.1 days

10. Rate of Complications inElective Surgery • Chung et al., 2008 Anesthesiology • Complication rate: 27.4% vs. 12.3% • Most common problem: SpO2 ≤ 90% • Especially on 3rd night post-op

11. Respiratory Disasters • Failure to secure the airway at induction • Airway obstruction soon after extubation • Respiratory arrest after the administration of opioids and/or sedation

12. Case Presentation • 55 y.o. male for laparoscopic nephrectomy with: • Obesity, BMI 42 • Hypertension • Type 2 diabetes • Stable coronary artery disease • Heart attack 3 years ago, treated with PTCA • GERD • Possible Difficult Airway • Known untreated OSA by O/N oximetry

13. Intra-operative T 9/10 Thoracic epidural placed Awake fiberoptic intubation Larger than expected incision Extubated in OR uneventfully PACU Required 50 mcg Fentanyl iv in PACU Reasonable pain control with thoracic epidural using hydromorphone & bupivacaine infusion Required 6 L/min O2 by mask for SpO2 of 96% No desaturations or obstructions noted in PACU records Case Continued

14. Case Continued • Surgical Ward • Thoracic epidural at 7mL/h • Patient reports increasing pain at 2130h • Surgeon’s sc morphine orders followed • 10 mg sc morphine administered • No concerns noted on assessment at 2200h

15. Case Continued • 0010h Pt found to be: • Obtunded • RR 22, Room air SpO2 76% • Nurse gives 0.4 mg naloxone (Narcan) • Patient is responsive to voice • Anaesthetist on-call paged, arrives & applies nasal airway, mask O2 • Eventually reintubates and admits to ICU

16. Case Continued • ABG’s:

17. Case Continued • Patient found to have had NSTEMI • Treated for laryngeal edema & extubated next day • Echocardiogram showed good function • Patient declined further investigations as preop MIBI scan normal

18. Swiss Cheese Model of Incident Occurrence Critical incident

19. What can we do about it? • Pre surgical screening & risk stratification • Pre surgical optimization • Intraop anaesthetic & surgical techniques • PAR monitoring/screening • Proper patient disposition to an area with appropriate monitoring

20. Preop screening & risk stratification for OSA • STOPBANG Questionnaire • History & physical • O/N Polysomnography (PSG) • O/N Oximetry

21. Snoring Tired Observed apneas High Blood Pressure BMI > 35 Age >50 Neck Circ > 40 cm Gender - male STOP BANG questionnaire

22. STOPBANG stats in the obese

23. SIM2PLE2 History • Sleepiness (Epworth Score) • Impotence • Menopause • Morning: • Headache • Confusion • Dry mouth or sore throat • Personality change • Learning impairment • Exudate (Night sweats) • EtOH or sedative use

24. Physical • Hard tissue craniofacial abnormalities • Retrognathia • Micrognathia • Brachycephaly • Soft-tissue enlargement: • Uvula • Tonsils • Tongue • Soft palate

25. Risk Stratification • History and Physical can rule out OSA • To risk stratify: • Overnight polysomnography (PSG) • Overnight oximetry

26. O/N Polysomnography • EEG • EOG, EMG • EKG • Airflow • Respiratory effort indicators • SpO2

27. Overnight Oximetry • Poor man’s PSG • Cannot rule out OSA • Tends to underestimate severity in those with moderate to severe OSA

28. Presurgical Optimization • Weight Loss • Cardiovascular disease risk modification • Blood pressure control • CHF management • Diabetes management • OSA therapy: • CPAP, BiPAP, dental appliances

29. Anaesthetic: Good: Regional Anaesthesia Local Anaesthesia NSAIDs Tylenol Bad: GA Deep sedation Long acting narcotics Neuraxial narcotics Basal PCA rates Surgical Good: Superficial Head up positioning Bad: Major cavitary Airway surgery Trendelenberg Anaesthetic & Surgical Techniques

30. Avoiding Airway Obstruction Post Extubation • Obtain Information: • OSA risk • Method and ease of intubation • Safe Extubation: • Awake • Upright • Verified full reversal of NMB • Extubate on 100% O2 • Preparation for reintubation • Immediate reinstitution of CPAP

31. PAR Care • Same principles listed apply: • Use CPAP if available • Avoid sedatives • Minimize narcotic use • Consider NSAIDs, Tylenol • Ask for local anaesthetic based techniques • Close monitoring & screening

32. PAR Monitoring/Screening • ASA OSA Guidelines: “Patients with OSA should be monitored for a median of three hours longer than their OSA counterparts before discharge from the facility.” “Monitoring patients with OSA should continue for a median of seven hours after the last episode of airway obstruction or hypoxemia while breathing room air in an unstimulating environment.”

33. Proposed FHA PAR Pathway • Min. 1 hr with continuous pulse oximetry • Upon meeting PAR discharge criteria: • Surgical daycare & home • Ward without OSA monitoring • Ward bed with OSA monitoring • ICU or SCCU with OSA cardio-respiratory monitoring

34. Surgical Daycare & Home • Drug requirements minimal • Apneas / Airway obstructions: none • SpO2 never < 88% • Therapy compliant preoperatively (CPAP)

35. Ward without OSA Monitoring • Drug requirements minimal • Apneas / Airway obstructions: none • SpO2 never < 88% • Therapy compliant preoperatively (CPAP) • Mild or Moderate OSA

36. Ward with OSA monitoring • Drug requirements not minimal • Apneas / Airway obstructions: noted • SpO2< 88% • Therapy: • compliant preoperatively (CPAP); or • Non-compliant but only mild or moderate OSA

37. ICU or SCCU with cardio-respiratory monitoring • Drug requirements not minimal • Apneas / Airway obstructions: noted • SpO2< 88% • Therapy non-compliant preoperatively and severe OSA

38. A Changing & Challenging Field • Relative lack of appreciation of OSA • Lack of PSG availability • Risk stratification still under development • Stretched post-op care resources & production pressure

39. Key points • OSA is common & it is bad perioperatively • We won’t identify all of those who have it & we are even worse at classifying severity • Need to be vigilant: • Extubate properly • Monitor for apneas, obstructions, desats • Watch narcotic & sedative use • Consider alternate post-op disposition & pain management techniques