Operative risk in patients with
Obstructive Sleep Apnea Syndrome
(OSAS).
Why give preference to RA?
Luc Sermeus
Antwerp University Hospital
Belgium
ESRA winterweek 2012
OSA:
characteristics
• Snoring
• Apnea caused by airway obstruction
• Arousal
Anesthesia
=
a state of unrousable unconsciousness
OSA: Preop assessment
• OSA already diagnosed
• OSA not (yet) diagnosed (80-95%)
• 82% men, 93% women
• Polysomnography / nocturnal oxymetry / Holter
• Cancel surgery?
OSAKA- questionary
“Half of Chinese anesthesiologists lacked sufficient
knowledge and had low confidence levels in dealing with
OSA patients”
C.L. Wang et al. Sleep Breath 2011, 16 (ahead of print)
Preop OSA: symptoms
• Snoring
• Men 44% > women 28%
• 30-60y, peak 50-60y
• Obesity (60-90%) BMI > 30kg/m²
• BMI: Western > Asian , prevalence OSA similar
5% in men, 2% in women
(Young, J Resp Crit Care Med 2002)
Preop OSA: symptoms
• Snoring
• Predisposition
• Alcohol, Upper airway infection
• Hypertrophic tonsils, nasal obstruction
• Craniofacial anatomy (Kushida Laryngoscopy
2000)
• Lower facial height, more backward position jaw
in Asian population
Preop OSA: symptoms
Airway obstruction with apnea
• Obesity
Correlation: fatty tissue lateral of pharynx & OSA
Neck Ø > 42-44 cm fast collapse of airway
• Micro- / retrognathia
• Hypertrophic tonsils, big tongue, position of hyod bone
• Maxillar hypoplasia, narrow oropharynx, shape of
airway
(Ishiguro, Oral Surg Med Path Radiol Endosc 2009)
Igor Fajdiga, MD, PhD
CHEST August 2005 vol. 128 no. 2 896-901
Normal
Apneic
Igor Fajdiga, MD, PhD
CHEST August 2005 vol. 128 no. 2 896-901
BMI = 32
Richard J. Schwab et al.
American Journal of Respiratory and Critical Care Medicine Vol 168. pp. 522-530, (2003)
Preop OSA: symptoms
Arousal
• O2↓, CO2↑, ventilatory effort↑, stretch-receptors↑
 “awake”
• Not totally conscious - muscle tone↑- obstruction↓
• Massive sympathetic activation
bradycardia tachycardia
AHT
Cardiac ischemia - CVA
OSA: pathophysiology
Cardiovascular changes
Sympathetic
Drive
Vasoconstriction
Periph. Resistance
Heart rate
Oxygen demand
Pharyngeal
collapse
in OSA
* LVH
BP
Intrathoracic
Pressure
* RV
dilatation
Venous return
Afterload
Preload
Myocardial
OxygenSupply
*Stroke Volume
*LVEF
*TD velocities of
LV and RV
OSA: consequences
•AHT: related to severity OSA (risk 10X↑)
•Arrhythmia's: nocturnal in 50%, risk2-4X↑ if hypoxemia↑
• Mostly NSVT
• Sinus arrest, second degree AV-block, VES, AF
•Cardiac ischemia:
14-28% = 5x normal
•Heart-failure: 11-37%
•Pulmonary HT 20-42%  Right heart-failure
OSA: consequences
• Hypoxemia  polycythemia
• Stroke: 62-77% of stroke has OSA
• Severity↑ of OSA = Risk↑ of stroke
• Terminal renal insuff: 40-60% = f(duration) of OSA
• Diabetes
• Edema UA
• Impaired chemosensitivity
OSA:
consequences
Cardio vascular risk ↑ with severity and duration OSA
Overall risk of CVD = x11
= 15-20% fatal complication if severe OSA >10j
Risk post therapy = mild OSA = 4-5%
Control = ±2%
Marin et al. Lancet
2005
Preop OSA: premedication
• Benzodiazepines: CAVE
Muscle tone↓  collapse  apnea  Sat↓
Pulsoxymetry / CPAP
• Anti-sialorrhea: Glycopyrrolate
• CPAP : to be started, if possible, 2w before
surgery
OSA + Consequences + Co-pathology
= perop / postop risk
Perop OSA: anesthetics
ALL ANESTHETICS :
•Negative effect on cardiac function
•Collapsibility↑
•Arousal response↓↓ if O2↓, CO2↑, obstruction
•Ventilatory response↓ if O2↓, CO2↑
•UA reflexes↓
Physiology: FRC
FRC = O2-reserve if apnea
• BMI↑ = FRC↓ + O2-consumption↑
• Supine position = FRC↓
• Anesthesia/sedation = FRC↓
 preoxygenation before induction of anesthesia
= filling FRC with ±100% O2
Perop OSA: UA
21,9% difficult UA if OSA ↔ normal
2,6%
Savva D.1994 Br J Anaesthesia 73(2):149-53
➡5% failed intubation (=100x normal)
66% with a difficult intubation had OSA
Chung F et al. 2008 Anesth Analg 107(3):915-20
Perop OSA: UA
• Difficult Upper Airway
• Experienced anesthetist
Inadequate face mask ventilation
Difficult ( > 2 attempts) intubation
• Predictive factors
• Complications
• Dental injury / UA trauma
• Severe hypoxia cerebral ischemia
+ laryngoscopy asystole
OSA: prediction difficult
UA
• Anatomical factors
• Craniofacial morphology / trauma / surgery
• Cervical mobility / mouth opening
• Micro- / retrognathia / macroglossia
• Long soft palate
• Mallampati
Mallampati
Mallampati 3-4 + OSA = difficult intubation
until proven otherwise
Cormack - Lehane
Difficult intubation
=
Difficult extubation!!!
OSA: Difficult extubation
Causes
• Anatomy
• Residual sedation
• Instrumentation UAW during intubation / surgery of UA
• Edema
• Blood
• Secretions
• Nasal packs
OSA: difficult extubation
•5% life threatening postextubation obstruction
following surgical treatment of OSA
OSA: difficult extubation
Pre requisites
• Complete recovery of muscle relaxation
• Wide awake / communicating
• Spontaneous breathing
adequate TV
oxygenation
• Semi sitting position FRC↑
OSA: difficult extubation
Pre requisites
•Stable haemodynamics
•CPAP +/- O2
•Re-intubation equipment ready
•Perop corticosteroids if necessary
•Intensive care / Medium care if necessary
OSA: postop complications
• Rebound REM ±3th day postop.
• Pain↓, surgical stress↓ ±normal sleep pattern
• Obstruction, apnea, sympathetic activation
• Hemodynamic instability (pt not yet recovered)
• Confused / CVA
• Disturbed wound healing
• Myocardial ischemia / infarction / sudden death
• NB: respiratory depression lasts for a week
(morphine??)
OSA: conclusions
• OSA = cause of cardio-vascular complications
• OSA = cause of difficult UA
• Enough reasons to prefer RA and to convince your
patient
Literature
Obstructive Sleep Apnea, Stroke, and Cardiovascular Diseases
Bagai, Kanika MD, MS
The Neurologist
Issue: Volume 16(6), November 2010, p 329–339