St Hilda's College
CDT Postgraduate Studentship in Healthcare Innovation (RCUK Digital Economy Programme grant number EP/G036861/1)
Breathing rate estimation using video photoplethysmography
Breathing rate is one of the vital signs most indicative of critical illness and cardiorespiratory deterioration. The ability to assess respiratory rate remotely and track its changes over time would provide a valuable addition to existing health surveillance systems.
Photoplethysmography (PPG) is a non-invasive optical technique that measures variations in skin blood volume and perfusion. The PPG signal contains components that are synchronous with both cardiac and respiratory rhythms. Typically, the optoelectronic setup of PPG has included a dedicated light source (e.g. at red and/or infra-red wave-lengths) but recent work has shown that pulse measurements can be acquired remotely using a consumer-level digital camera with normal ambient light as the illumination source. In light of these recent developments, the purpose of my research is to develop an accurate camera-based algorithm for measuring the respiratory rate of renal failure patients undergoing outpatient haemodialysis. If PPG proves to be a useful means for monitoring respiratory rate in this patient group it may be possible to design a single non-contact sensor to monitor breathing rate in addition to multiple other vital signs simultaneously.