Question 27.1

List the features of the device depicted below.


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College Answer

Hydrophobic pleated filter for heat and moisture exchange
Bacterial and viral filtration properties
Filter protects against liquid and airborne contamination
Minimal resistance to airflow
Luer lock gas sampling port (connects to ETCO2 monitoring)
15mm/22mm ISO standard connectors
Disposable single patient use


This question invites the candidate to show their appreciation for the basic features of their everyday equipment.

Well, no. It really tests the candidates anaesthetic background. The anaesthetic trainee will have a detailed (some may say, intimate) understanding of all their various gadgets.

This thing is a heat and moisture exchanger (HME) and it is discussed in greater detail elsewhere.

There really isnt much to it. Ultimately, its a plastic box with cardboard in it.

The features listed in the college answer will suffice.

Here they are in point form, battered and lightly fried.

  • Single use item
  • Transparent plastic body
  • 30-40ml of apparatus dead space
  • Hydrophobic pleated filter
  • Antimicrobial filter lining
  • ETCO2 monitoring port with Luer lock connector
  • Standardised ISO ventilation equipment connectors