Obstructive sleep apnea and anesthesia

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Obstructive sleep apnea and anesthesia

• Practice guidelines for the perioperative
  management of patients with obstructive sleep
  apnea. Anesthesiology 2006 1041081-93
• Risks of general anaesthesia in people with
  obstructive sleep apnoea. BMJ 2004 329 955-959
• Unrecognized Sleep Apnea in the Surgical Patient.
  Chest 2006129198-205

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Introduction
Recovery function
? Brain
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Definition of OSA (obstructive sleep apnea)

• Apnea
• A pause of ?10 sec. in breathing during sleep
  despite continuing ventilatory effort
• Hypopnea
• gt 50 diminishing of airflow or oxygen
  desaturations ? 3 for ?10 sec.
• Obstructive sleep apnea
• AHI (apneic-hypopneic index) by polysomnography
• ? 5 apneas/hr
• ? 15 hypopneas/hr

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• Predisposing factors
• Obesity (BMI gt30)
• A large neck circumference (gt44 cm)
• Age
• Male
• Use of alcohol

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How does perioperative state impact sleep?

• Both anesthesia and surgery affect the
  architecture of sleep
• Sleep deprivation and fragmentation
• REM sleep is usually absent on the 1st
  postoperative night
• REM associated hypoxemia in the late
  postoperative period
• Apneas desaturations
• Surgical stress gtgt anesthesia
• Location type of the surgery
• Morphine

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Summery

• Postoperative REM sleep rebound opioid
  administration supine posture gt aggravate
  sleep-disordered breathing
• Sedatives analgesics residual effects of
  anesthetics
• ?pharyngeal tone
• ?ventilatory and arousal responses to hypoxia,
  hypercarbia, and obstruction

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How can OSA affect perioperative outcomes?

• REM sleep gt hypoxemia gt sympathetic avtivation
• Hemodynamic instability
• Attenuated responses to vasopressors
• Myocardial ischemia and infarction
• Stroke
• Mental confusion
• Wound breakdown

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• Sleep deprivation
• A lower threshold for upper airway collapse
• ?responsiveness to hypercapnia and hypoxia
• Postoperative delirium
• Cardiac arrhythmias
• Sinus bradytachyarrhythmia
• VPCs
• Sinus pauses of 2-13 sec.
• Second-degree AV block
• Atrial fibrillation

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What is the most reliable tool to assess OSA in
the perioperative setting?

• Preoperative visit
• Hx, S/S, PE, laboratory studies
• Intraoperative period
• Problems with the maintenance of the airway
• Difficult to intubate
• Snoring having obstruction observed
  postoperatively.
• An airway obstruction that is out of proportion
  to the apparent degree of sedation
• A pronounced tendency for upper airway
  obstruction during anesthesia or recovery from it

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Staging system of Mallampati
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• The reliable tools
• Polysomnography gold standard
• Preoperative overnight oximetry
• SARs (significant abnormalities of respiration)
• SpO2 ? 4 ? 5 times in 1 h
• Supine RDI (respiratory disturbance index )
• AHI
• Number of apneas / hypopneas per hour total sleep
  time
• RERA (respiratory effort-related arousal)
• ?respiratory effort for ? 10 s leading to an
  arousal from sleep

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Preoperative preparation

• Preoperative weight loss
• Preoperative use of mandibular advancement or
  oral appliances
• Preoperative mechanical ventilation assist
• CPAP (continuous positive airway pressure)
• NIPPV (noninvasive positive-pressure ventilation)
  
• BiPAP (bilevel positive airway pressure)
• Preoperative medications

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Without CPAP
With CPAP
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Intraoperative management
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• Choice of anesthetic technique
• Peripheral surgery
• Local anesthesia
• Peripheral nerve block
• Regional anesthesia
• Intraabdominal surgery equivocal

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• Airway management
• A secured airway
• Deep sedation for superficial procedures
• Moderate or deep sedation for procedures
  involving the upper airway
• Extubated
• Fully awake
• Full reversal of neruromuscular blockade
• Semiupright position
• Patient monitoring
• Respiratory CO2

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Postoperative management

• Risk factors for respiratory depression
• Systemic and neuraxial administration of opioids
• Administration of sedatives
• Site and invasiveness of surgical procedure
• Underlying severity of OSA
• Exacerbation of respiratory depression may occur
  on the 3rd or 4th postoperative day as REM
  rebound occurs

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Postoperative analgesia

• Regional analgesic techniques rather than
  systemic opioids reduce the likelihood of adverse
  outcomes
• Exclusion of opioids from neuraxial postoperative
  analgesia reduces risks as compared with
  neuraxial techniques which include opioids
• Adding a basal infusion to PCA results in an
  increased incidence of hypoxemia

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Oxygenation

• The use of postextubation supplemental oxygen to
  improve the oxygen saturation levels
• Increase the duration of apneic episodes
• May hinder detection of atelectasis, transient
  apnea, and hypoventilation by pulse oximetry
• CPAP or NIPPV, with or without supplemental
  oxygen, should continuously administered when
  feasible

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Patient positioning

• Avoid supine position during the recovery

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Monitoring

• Pulse oximetry should be applied until room air
  oxygen saturation remains gt 90 during sleep
• Continuous monitoring should be maintained as
  long as patients remain at increased risk

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Thank you for your attention!!
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