Optimisation of haemodialysis treatment
Researchers: Yasmina Borhani, Dr David Meredith, Dr Clare McEwen, Prof. Lionel Tarassenko
Clinical collaborators: Prof. Chris Pugh (Renal Unit, Churchill Hospital)
Funding: Oxford Biomedical Research Centre (OxBRC)
Patients on haemodialysis are given three 4-hour treatments per week to achieve reasonable fluid and biochemical homeostasis. No two dialyses are absolutely identical and there is an inherent asymmetry in the week because the dialyses are separated by 44, 52 or 68-hour intervals. At present, monitoring of patients during dialysis includes recording the patient's weight before and after a session, their pulse and blood pressure before, during and at the end of a session, and in some cases a measurement of variation in haematocrit during the session to obtain an indication of changes in blood volume. The patient's temperature is also generally measured at least once during a session.
There is a lot of variability between patients in terms of their cardiovascular fitness, or autonomic responses and drug therapy. As many as 25% of patients experience sudden hypotension, cramps, dizziness or nausea (intra-dialytic hypotension). A large-scale observational study (80 patients for a minimum of 4 dialysis sessions) has been completed in the Renal Unit at the Churchill Hospital, in which vital signs were acquired continuously from patients undergoing routine care during dialysis. This has provided data to determine how parameters extracted from vital signs change at the time of intra-dialytic hypotension, and has allowed us to construct patient-specific models in an attempt to predict these adverse events.
This study has also been the test bed for a digital camera system for non-contact sensing of physiological parameters.