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

Levitsky – LSU

Normal State

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

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

Polysomnography

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

Sleep Apnea Event

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

Symptoms of OSA

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

Sleep Apnea Event

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

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

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 Curr Opin Anaesthesiol 22:405 –411

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

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

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

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

Symptoms of OSA

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

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

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

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

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

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 Caples – Mayo Clinic Ann Intern Med. 2005;142:187-197.

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 + Caples – Mayo Clinic Ann Intern Med. 2005;142:187-197.

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

Identification of Patients with OSA

Chung – Toronto Western Hospital Curr Opin Anaesthesiol 22:405 –411

Identification of Perioperative Risk

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

Liang – MGH Anesthesiology 2008; 108:998 –1003

Liang – MGH Anesthesiology 2008; 108:998 –1003

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

Outpatient Surgery?

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

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

STOP BANG vs. ASA guidelines

Sensitivity STOP-BANG ASA Guidelines AHI >5 83.6

72.1

AHI >15 92.9

78.6

AHI >30 100 87.2

 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

QUESTIONS?