The correspondence article 'Where is the leak? ^'1 caught my eyes, not only because it is an eye opener to all of us but also reminded me of a similar incident.

Catheter mounts are of great use to add ‘that extra length’ to the breathing system when needed.  Each catheter mount has a 22 mm female / 15 mm male end to connect to the breathing system and 15 mm female end to connect to the endotracheal tube or laryngeal mask airway.  The length is around 15 cm.

While this provides the extra length required, it also increases the dead space by about 20 – 40 mls.  Thus, I tend not to use catheter mount as much as possible to avoid an increase in dead space. 

I anaesthetised an adult patient for a maxillofacial case, which required nasal intubation.  I used a north facing preformed (RAE) tube for intubation.  After transferring the patient to the operating table, I noted that catheter mount is necessary to avoid any drag and to prevent any chance of accidental extubation.  When I requested for a catheter mount, I was presented with the one shown in picture.

In this, connectors at both end of the catheter mount were 15 mm female, which normally is attached to the endotracheal tube / laryngeal mask airway.

This was not an acute situation and we had time to use an alternative catheter mount. However, incidences like this in an emergency situation may be catastrophic, especially if this is the only one stocked in the trolley. 

Thus, I totally agree and support the suggestions made by K K Ramaswamy, A Bogdanov and M Alcock¹ on checking the integrity and leakage of catheter mounts immediately before use.

 Dr M Lohit

Northampton General Hospital, Northampton,

E-mail: lohitm69@googlemail.com 

Reference:

1.      K. K. Ramaswamy, A. Bogdanov and M. Alcock Anaesthesia 2010; 65: 311.

It would appear Dr Lohit and Ramaswamy may have presented a pretty convincing case to eliminate catheter mounts altogether. Each has described an account of errors or defects, which they have personally witnessed, presumably as a result of either manufacture or storage. Furthermore, Ramaswamy's original letter referred to three further cases where ventilation of the patients' lungs was compromised by faulty catheter mounts.

I was weaned off catheter mounts when I went to work in the US some years ago. In the US, the practice is to use uncut endotracheal tubes and connect them directly to the breathing system. My new colleagues listened with interest as I explained that in the UK we cut our tubes to the 'correct' length, and threw the remnant away (between 6-8cm approximately), before introducing another piece of tubing to address the deficit we have just created. "What would you wanna do that for?" was the innocent reply. Thus, equipped with the knowledge that no-one had even heard of a catheter mount let alone used one, I was able to see that my request for this item was going to be fruitless. The university teaching hospital in which I found myself, with 21 operating theatres was equipped to accommodate the region's cardiac and liver transplant programme along with a neurosurgical, maxillofacial and burns facility, and did not appear to be hampered by the absence of this particular piece of equipment.

The use of a catheter mount generates an additional connection between elements of the breathing system, and thus another potential source of disconnection or leakage. Single-use status means there is both a direct cost to the hospital, and an indirect environmental cost, which is now becoming all too apparent. To use Dr Lohit's own figure, as much as half the length of the catheter mount may replace the length of an oral endotracheal tube that has been discarded after cutting it. The fact that the 15 mm endotracheal tube connector is positioned further away from the mouth, if the tube has not been cut, avoids the embarrassment of trying to explain why the connector has eroded into and damaged the lips after a long surgical case.

Whilst I appreciate that there will always be occassional circumstances in which catheter mounts may be genuinely useful, is perhaps the best way to prevent the complications associated with these devices is to avoid using them?

Dr D R Uncles

Worthing Hospital, Worthing, West Sussex.

david.uncles@WSHT.nhs.uk