Police Investigate Blocked Anaesthetic Breathing Circuits


In 2002, 2 patient deaths and a cluster of other adverse events from blocked anaesthetic breathing circuits lead to a police investigation. Operation Orcadian was set up in part to exclude foul play.

Several cases were caused by detachable caps from filters coming off and obstructing the breathing circuit.

The investigation concluded ‘the apparent clustering of cases in time and place, although initially suggestive of malicious acts, was plausibly attributed to chance‘.

Perhaps we should be concerned that, over 15 years later, the conditions which led to these adverse events still exist today.

You can help change this.

If your hospital uses breathing filters with non-tethered caps suggest their replacement with ones with tethered caps. Perhaps forward this post to heads of department who can institute the change.

Dr Rhys Thomas discusses the features of an Ideal Breathing Circuit Filter in this report (see here). Pleated mechanical filters reduce the risk of contamination of the machine side of the anaesthetic circuit more than electrostatic ones (see here & see here).

This review from the MHRA in the U.K. provides an assessment of over a hundred different breathing circuit filters (see here).

We support the standardisation of Breathing Circuit Filters so that they are optimised for patient safety & care.

Please click on the images below for suitable suppliers. Please let us know if you are aware of any others and we will add to the list:

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