Research: BREATHTAKING

It is often vital to measure an individual's respiration rate but the equipment involved, such as face-masks or an electrocardiogram, is cumbersome and expensive. Now, thanks to new software, accurate measurements can be obtained from a monitoring device already widely used in hospitals.

Professor Paul Addison and colleagues at Napier University in Edinburgh hit upon their innovation while analysing the signals from a pulse oximeter – a medical device used to measure oxygen saturation and heart rate. A light probe is clipped to the person's finger, and transmitted light is detected and analysed.

Using a relatively new technique, wavelet transform, to analyse the pulse oximeter signal (called the photoplethysmogram or pleth), the researchers realised that some of the regular patterns in the signal were caused by the person's breathing. By refining their software, they were able to measure both respiratory rate and respiratory effort automatically, continuously and non-invasively.

Recent clinical trials on premature babies have confirmed the effectiveness of the technique. The next step is to design a pulse oximeter in which this extra measuring facility is already an integral part.

This technology was developed by researchers at CardioDigital Ltd – a company set up in 2001 by Professor Addison, Dr Brendan McGuckin and Dr Jamie Watson. In the longer term, they aim to develop other tools to extract extra useful information from medical signals.