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
Normal State
Alae nasi
Tensor palatini
Genioglossis
Geniohyoid
Thyrohyoid
Sternohyoid
Levitsky – LSU
Adv Physiol Educ 32: 196–202, 2008
Polysomnography
•
•
•
•
•
•
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
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  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
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
AHI >5
AHI >15
AHI >30
STOP-BANG
83.6
92.9
100
ASA Guidelines
72.1
78.6
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?