Face Mask Capnography for Procedural Sedation – tip from John Larkin

Here’s another method of monitoring EtCO2 during procedural sedation from John Larkin, an Advanced Trainee from Joondalup in WA. It’s another way of attaching a “main-stream” EtCO2 sensor to a face mask. Here’s how John does it:

“We used the mainstream monitor connected to a cut paediatric ETT, we used a size 3, which with a bit of mask hole dilating fits nicely. This worked really well, on a side note a can confirm that a 16G – 20G cannula works nicely for sidestream monitoring via mask”.

Here’s the pictures of John’s setup:



Also, a quick safety note/disclaimer. While the methods we’ve described for monitoring EtCO2 seem logical and intuitive, remember these methods have not been formally tested/studied, nor had their safety formally assessed. There are a number of reasons these systems may not work or give accurate EtCO2 readings:
– Disconnection of any of the improvised connectors
– Blockage of any of the tubing by condensation or kinking
– Disruption of the CO2 flow to the sensor by the oxygen flowing through the mask
So by all means try them out, but please utilise all of your other standard monitors, and apply the same principles of anaesthetic safety that you’d normally use.

Please feel free to send in any other improvised ED devices that you’ve encountered, and we’ll post them!

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