We read with interest the correspondence article ‘Potential contamination of side stream capnography systems during regional anaesthesia’ [1]. Whilst it shows that they are thinking laterally about the safe management of their patients, we believe what they are proposing is a poor solution to a problem already solved.

The authors suggested modifying a Hudson type facemask to include capnography, using a filter taken from a drawing up needle, in order to prevent infection tracking down the capnography tubing. By doing this, they become the manufacturers of the device and liable for any problems that may arise.

In our hospital, we have been using the Capnomask^® (http://www.mediplus.co.uk/products/anaesthetics/Capnomask.pdf) in the last year, in order to monitor the respiratory rate and end-tidal carbon dioxide of patients undergoing procedures  under regional anaesthesia, with or without sedation. This mask employs a 200 cm oxygen delivery tube, and a 250 cm side stream sampling line with 0.22 µm filter.

We recommend that all anaesthetists should use purpose designed equipment, where it is available, and not use or encourage home built equipment in the operating theatre.

Dr M Lohit

Dr C Frerk

Department of Anaesthesia, Northampton General Hospital, Northampton, U.K. 

E-mail: lohitm69@googlemail.com 

References

1. S Bolton and E Abd Elrazek Anaesthesia 2009; 64: 1269.