Thread by @cliffreid

The iGel is a great supraglottic airway device

But like other supraglottic airway devices (SAD) it's not foolproof

Here's how to maximise your success with the iGel - a thread 🧵

Adequately positioned SADs produce a good seal and no leak

Ideally the iGel cuff should sit snugly over the larynx

The tip will be in the proximal oesophagus which also allows for the passage of a gastric tube through a dedicated lumen in the device

For the right fit it needs to be:

1. Right size

2. Inserted correctly

1. Right size

The manufacturer recommends a weight based formula
size 3 for weight < 50 kg
size 4 for weight 50–90 kg
size 5 for weight > 90 kg

However absolute body weight does not reliably predict airway size

When people eat more and put on weight they don't necessarily put on more airway

An alternative sex based formula has been proposed - size 4 for women and size 5 for men

In a comparative study of weight-based vs sex-based insertion size selection in 900 patients, sex-based was significantly more successful

pubmed.ncbi.nlm.nih.gov/30336273/

Now we've selected size we're onto point 2: Inserting Correctly

To get to the right seating position over the larynx the iGel has to get round the tongue

Otherwise insertion can potentially catch the tongue carrying it posteriorly & even folding it, preventing proper placement

One way to clear the tongue for a single operator is rotation

Eg. inserting it into the mouth in the 'normal' orientation, rotating it 90° while inserting further then rotating 90° in the other direction to seat it

Or inserting it 'upside down' & rotating 180° on insertion

Studies of these methods suggest there may be some advantage using a rotation technique - faster insertion, higher success rate, higher leak pressure, and less blood staining

pubmed.ncbi.nlm.nih.gov/24773470/

journals.lww.com/ijaweb/Fulltex…

Alternatively, getting round the tongue can be achieved by moving the tongue forward, by means of a chin lift / jaw thrust

This can be achieved by a single operator, sometimes with the thumb in the mouth, although this isn't recommended in non-muscle relaxed patients

The simplest & easiest way to achieve tongue clearance is to have an assistant provide the airway opening manoeuvres while the operator inserts the iGel

'2 person technique' is recommended for optimal facemask ventilation, & is appropriate for optimal supraglottic insertion too

My suggested 4 step sequence for simple iGel insertion for non-expert providers (which in my view would include most non-anaesthetists) would be as follows

1. Optimise patient position

Ear-to-sternal notch horizontal alignment with neck flexion never lets you down. Also called 'flextension' this is identical to the optimal direct laryngoscopy position

2. Assistant opens mouth while iGel is inserted into oral cavity

3. Assistant thrusts jaw (thumbs on maxilla) while iGel is fully inserted

4. Waveform capnography is applied and gentle bagging via the iGel is started

Summary:
iGels = great but need to be sized & inserted correctly
Size F=4 M=5
Position patient -flextension
2 person insertion technique - mouth opening & then jaw thrust
Assess for ventilation, leak, & connect ETCO2
Extra Tip: easier in paralysed patient / no cricoid pressure

See here for tips on best attempt at supraglottic insertion as part of the Vortex approach

vortexapproach.org/sga

In this video one of my airway mentors @OSWinNSW covers tips on iGel insertion which I think will be of use to all us prehospital and inhospital critical care clinicians who do not get daily exposure to these devices in the operating room

Thanks for reading!

End of 🧵