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Anne-Kathrin Brill – update April 2014

Over the last few months at the Royal Brompton Hospital and Imperial College in London, I have made progress with my research project.

I have been aiming to find a technique to measure the pressure exerted by face masks during non-invasive ventilation (NIV). I have investigated different options, including small catheters, force and pressure sensors, and pressure indicating films, and have found a suitable system, which I have been familiarising myself with.

The system has a very thin and flexible sensor which can be placed between the facial skin and parts of the mask and measures the pressure applied to the face. It also gives direct visual feedback by displaying the pressure intensity in different colours (with red being the areas with the highest and blue being the lowest pressure applied) on a screen.

To gain more information we have lined up a series of small projects to work out the pressure exerted on the face by masks in healthy volunteers and in people with lung conditions. We will also evaluate factors that could affect the pressure on the skin, e.g. different mask materials, change of posture, ventilator settings, application of skin dressings, or the addition of a gastric tube. This information may help us understand how we can decrease any negative effects of high pressure on the face, such as skin damage during NIV, and improve mask design.

Improving the mask fitting process

Besides looking at techniques to measure mask pressure, I have worked on methods to make mask fitting better and prevent pressure ulcers. Often when people require NIV they may be new to the treatment and not realise when the mask is causing more discomfort than is normal, or they may be mildly dazed due to an illness and not be able to provide any feedback on the fitting of the mask.

For unexperienced healthcare workers, it can be difficult not to over-tighten the mask straps and achieve a good fit in these situations. We are therefore trying to improve mask fitting competency by using the visual feedback of the pressure sensor as a teaching tool.

The sensor can be placed on parts of the face, e.g. the nasal bridge. During a fitting, the pressure exerted is displayed on a screen in real-time, and areas of high or low pressure can be identified by different colours. Through seeing the effects of moving the mask or adjusting the straps on the monitor in this way, the practitioner can get immediate feedback on the amount of pressure they create with the mask, and learn to correct it. 

In addition to this project, I have also worked alongside the nurses and wound care specialists in the hospital, to update the hospital’s guidelines on prevention and management of facial pressure ulcers in NIV. These are now routinely used in the hospital.