Trial of an at home screening program for investigation of obstructive sleep apnoea in rail safety workers

Participants who meet the inclusion criteria will undertake an at home sleep assessment via a portable home monitoring device to screen for obstructive sleep apnoea. Participants will be given instruction on how to operate and administer this device by an occupational health nurse during their routine medical assessments. The device is about the size of a mobile telephone. Participants will take the device home for use on the night of their periodic Rail Safety assessment. The device (the "ApneaLink") is a portable battery powered 3 channel unit that measures: 1. nasal flow (via nasal cannulae) 2. oxygen saturation (via finger sensor) 3. chest expansion (via a chest strap) Participants will undertake the study in their own home/bed, and will be instructed to attach the leads and turn the device on around 15-20 minutes before sleep. They will then be asked to turn the unit off when they wake the next morning, after preferably at least 6 hours of sleep time in between. The above parameters are recorded via the unit, and data will be extracted the next day once the unit is returned to study centre. The data will then be extracted and analysed to assess whether or not there are any periods of apnoea (cessation of breathing) or hyponoea (reduced breathing) during sleep. A sleep physician will then interpret the data and give opinion as to whether or not there are any characteristics of obstructive sleep apnoea.