• always put a bite block in, esp if patient going to PACU with LMA
• size LMA to PHARYNX, not weight
  • although, LMA packaging recommends sizing to weight
• ?leak

• pressure ulcers

  • esp with long cases > 2 hours
  • do not overinflate

• beware trauma to tongue and hypoglossal nerve

• size

• iGel

  • Size 1 = Neonate = 2-5 kg

• LMA or ETT?

  • LMA benefits
    • ease of insertion
      • usually less airway manipulation
    • can be adequate even if NMB required
    • avoids stimulation and risks of laryngoscopy
  • main risks of LMA
    • aspiration = can pass NG to empty stomach
      • ⬆intra-abdominal pressures (laparoscopy / obesity)
    • airway leak
      • gastric insufflation
      • ⬆peak airway pressures in obese patients
  • ETT benefits
    • secure airway
    • prevents intraop laryngospasm
    • allows higher ventilation pressures
    • facilitates suction
  • Duration less absolute contraindication
    • Even 10 hours can be ok
    • Main risk is pressure injury

• Pharyngeal mucosa
  • laceration, bleeding
• Laryngeal apparatus
  • arytenoid dislocation
  • RLN injury = altered voice
• Uvula
  • Trauma, leading to ischaemia and necrosis
• Epiglottis
  • bruising, laceration
• Tongue
  • Frenular injury
  • lingual nerve injury = sensory, taste
  • hypoglossal N injury = dysphagia
• Teeth
  • Displacement
  • Fracture of roots
• Lips
  • laceration, bleeding

• ensure adequate depth of anaesthesia
  • especially in young patients
  • young male = can have 4 mg/kg propofol = 400 mg
  • avoid the "in-between" zone when anaesthesia is inadequate
  • Loss of eyelash reflex
  • No response to jaw thrust, which is very stimulating
• short-acting opioid
  • alfentanil 10 mcg/kg
  • propofol is best at blunting upper AW reflexes
• intubate the oesophagus with bougie
  • railroad LMA over

• one sturdy method
  • tape from cheek
    • maxillae are fixed = stable points for securing tape
  • then tape across upper lip
  • go around LMA twice
  • then tape across upper lip
  • then tape to cheek

• maximum 60 cm H2O
• but adequate seal often at much lower pressures
• and caution mucosal ischaemia

• use PCV = so max pressure can be set

• can remove when awake
  • removal in PACU
  • remove in OT
• remove deep
  • ensure adequate Vt before removal
  • deep enough to allow LMA removal without precipitating LS
  • light enough for spontaneous ventilation and maintain airway
  • beware obstruction and hypoxia en route to PACU

• cause
  • anatomical
    • tongue
    • LMA folded / twisted
    • solution = remove and re-insert
  • tone
    • laryngeal
      • laryngospasm
    • pharyngeal
      • deepen anaesthesia = propofol
      • paralyse = NMBA
    • often a closed glottis (ie. too light)
    • will often improve with time and mucosal adjustment
• confirm leak + quantify
  • If bellows fill on 0.5 Lpm and PEEP 5 then good seal
  • use spirometry and compare TVinsp and TVexp
  • ⬆MV = 500 x 12 and 1 L/min FGF
• reposition
  • try pulling out a bit
    • if this works, then LMA too small
  • try deflating and pushing in
    • if this works, then LMA too large
• try different size

• 1st vs 2nd generation
  • Differences
    • higher leak pressures = 37 cm H2O vs 20 cm H2O
    • able to pass OGT
    • more rigid = more risk trauma
    • integrated bite block
  • Similarities
    • easy insertion
    • do not prevent soiled airway with aspiration
• ENT procedures that should NOT have LMA
  • Cochlear implant = sterility concerns, if AW adjustment is needed
  • Staphectomy / middle ear surgery, due to need for immobility for delicate surgery

Complications Associated with the Use of Supraglottic Airway Devices in Perioperative Medicine 2015

Iatrogenic airway injury

https://www.lmaco.com/sites/default/files/31817-LMA-Switch-A4-0214-LORES-fnl.pdf

Second Generation Supraglottic Airway (SGA) Devices

https://www.intersurgical.com/products/airway-management/i-gel-supraglottic-airway