Obstructive Sleep Apnea Cory M. Furse, MD, MPH

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.

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

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

Polysomnography Electroencephalogram Electrooculogram Electromyogram of respiratory muscles Airflow at the nose or mouth via thermistor End-tidal CO 2 Impedance plethysmography for chest/abdomen movement EKG, NIBP, and SpO 2 Adv Physiol Educ 32: 196–202, 2008Levitsky – LSU

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

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

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

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

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 – LSUAdv Physiol Educ 32: 196–202, 2008

Curr Opin Anaesthesiol 22:405–411 Epidemiology  ~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! Chung – Toronto Western Hospital

Lanphier EH – SUNY at BuffaloJ Appl Physiol 18: , 1963

Lanphier EH – SUNY at BuffaloJ Appl Physiol 18: , 1963

Lanphier EH – SUNY at BuffaloJ Appl Physiol 18: , 1963

Lanphier EH – SUNY at BuffaloJ Appl Physiol 18: , 1963

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

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

Adv Physiol Educ 32: 196–202, 2008

Levitsky – LSUAdv Physiol Educ 32: 196–202, 2008

Symptoms of OSA  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 Adv Physiol Educ 32: 196–202, 2008Levitsky – LSU

Somers – IowaJ. Clin. Invest :

Signs of OSA  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 Ann Intern Med. 2005;142: Caples – Mayo Clinic

Signs of OSA  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 + Ann Intern Med. 2005;142: Caples – Mayo Clinic

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

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

Gross – Farmington, CTAnesthesiology 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 Gross – Farmington, CTAnesthesiology 2006; 104:1081–93

Chung – Toronto Western HospitalCurr Opin Anaesthesiol 22:405–411 Identification of Patients with OSA

Identification of Perioperative Risk Gross – Farmington, CTAnesthesiology 2006; 104:1081–93

Preoperative Preparation Gross – Farmington, CTAnesthesiology 2006; 104:1081–93  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

Liang – MGHAnesthesiology 2008; 108:998–1003

Liang – MGHAnesthesiology 2008; 108:998–1003

Intraoperative Management Gross – Farmington, CTAnesthesiology 2006; 104:1081–93  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

Postoperative Management Gross – Farmington, CTAnesthesiology 2006; 104:1081–93  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

Outpatient Surgery? Gross – Farmington, CTAnesthesiology 2006; 104:1081–93

Discharge Criteria Gross – Farmington, CTAnesthesiology 2006; 104:1081–93  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

Appendix: Gross – Farmington, CTAnesthesiology 2006; 104:1081–93  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”

Chung – University of TorontoAnesthesiology 2008; 108:812–21

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 TorontoAnesthesiology 2008; 108:812–21

STOP BANG vs. ASA guidelines SensitivityAHI >5AHI >15AHI >30 STOP-BANG ASA Guidelines  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 TorontoAnesthesiology 2008; 108:822–830

QUESTIONS?