Role of LMA in failed intubation


Examiner’s reports:

·        ASA difficult airway algorithm

·        Mention pros and cons of different types of LMA

·        Appropriate ETT sizes and techniques of use through an LMA

·        Ventilator pressures

·        Role of cricoid pressure

·        Risk of aspiration

·        Urgent vs non-urgent


Types of LMAs and their advantages


·      Flexible – e.g. if anatomically abnormal airway

·      Small – e.g. if very small mouth or airway mass

·      Readily available

·      Familiar

·      Easy to insert

·      Can be rotated during difficult insertion

·      Adjustable cuff

·      Insufflation pressure 20cmH2O


·      Allow NGT

·      Allow intubation

·      Higher insufflation pressure 25cmH2O

·      Adjustable cuff


·      Suitable for cardiac arrest

·      Allow intubation (3 -> 6, 4-> 7, 5 -> 8)

·      Allow NGT

·      Very high safe insufflation pressure 30cmH2O

·      igel: moulds to airway, no need to inflate


Role of LMA in failed intubation: in this case laparotomy

Main function

·      Supraglottic device

·      Allow oxygenation ± ventilation

·      Easy to insert

·      Part of back-up plan in addition to bag-mask and surgical airway

·      Helps prevent repeat attempts at laryngoscopy causing transition from CI to CICO

·      Different LMAs suit different airway – individual, ethnicity, pathology

1.Proceed with case

·      Consider urgency and duration:

o   Urgent and short -> favour proceeding

o   Non-urgent and long -> favour wakeup and defer

o   Discuss with surgeon

o   Consider temporizing surgery instead

·      Prefer spont vent:

o   Improves seal

o   Lower risk of gastric insufflation

·      If IPPV then needs to ventilate adequately

o   ~20cmH2O classic, 25cm most 2nd gen, 30cmH2O iGel

o   Beware if obese, head down, lung disease, laparoscopy

·      Needs to be low risk of aspiration

o   Mitigate with NGT via 2nd gen device, on free drainage

o   Cricoid pressure may distort seal and not a long term solution

2.Bridge to ETT

·      Via intubating LMA: smaller ETT easier to insert

o   Through fastrach (admits size 6-8)

o   Through iGel (3 -> 6.0, 4 -> 7.0, 5 -> 8.0)

o   Insertion: fibreoptic -> exchange catheter -> ETT

o   Must confirm intubation with capnography

o   Safest to keep LMA in situ rather than remove

·      Size of ETT must be adequate:

o   Beware obstructive lung disease (impaired exhalation)

o   Beware very large patient (failure to seal with small ETT)

3.Bridge to FONA

·      May be indicated if distorting airway pathology (e.g. abscess, tumour) cf. anterior larynx

·      Swelling from intubation attempts may make emergence dangerous

·      Tracheostomy can be performed with LMA in situ

4.Wake up

·      Considerations:

o   Muscle relaxant – give sugammadex 16mg/kg if roc or vec used

o   Airway swelling – consider dexamethasone 0.6mg/kg

o   Location – wake-up in theatre

o   Disposition – consider ICU if airway swollen



Feedback welcome at