Hospital of the Future
Researchers: Dr Tim Bonnici, Dr David Wong, Prof. Lionel Tarassenko
Clinical collaborators: Mr Peter McCulloch, Dr Richard Beale (Guy’s and St Thomas’s, London), Dr Peter Watkinson
Funding: RCUK Digital Economy Programme (follow-on funding from Oxford Biomedical Research Centre)
90% of adult in-hospital patients are on general wards, where their vital signs (heart rate, breathing rate, blood pressure, level of consciousness, oxygen saturation and temperature) are observed intermittently by nursing staff (typically 8-hourly or 12-hourly). In 2007, the National Institute for Health and Clinical Excellence (NICE) recommended that physiological track-and-trigger systems should be used to monitor all adult ward patients in acute hospitals. These systems are based on early warning scores (EWS) calculated from the values of the vital signs.
As part of this project, we have designed an evidence-based early warning score, using a large dataset of 64,000 hours of vital-sign data acquired in previous clinical trials in Oxford and in the US. Univariate population models of normality were constructed to convert the vital sign values into an integer “abnormality score”, which is then summed over all vital signs (as described in a research paper published in August 2011 in Resuscitation). At the same time, the flowcharts for triggering escalation of care were also re-designed. The new track-and-trigger charts were successfully deployed in the John Radcliffe Hospital in early 2011. Today all adult ward patients in the acute hospitals in the Oxford University Hospitals (OUH) Trust are assessed using the evidence-based track-and-trigger charts. In the first year following the introduction of these new charts, the number of cardiac arrests in the Trust decreased by 10%.
We have now set up a sub-project to design an electronic version of our evidence-based track-and-trigger charts (System for Electronic Nursing Documentation – SEND). This became a CQUIN project for the Oxford University Hospital Trust in April 2012. The system architecture has been designed to be flexible and future-proof to allow for direct input from patient monitors and automated export of the vital sign data into the Trust’s Cerner Millennium Electronic Patient Record (EPR) and similar NHS IT systems.
We have also been investigating real-time vital-sign monitoring (heart rate, oxygen saturation and breathing rate) of high-risk, ambulatory patients using wireless sensors linked via wif-fi to the nursing station on the ward. We investigated body-worn sensor systems commercially available in the UK (e.g. from Intelesens and Hidalgo) and in the US (Proteus patch). After pilot testing on healthy volunteers and elderly patients in gerontology wards, we devised a protocol for testing wireless sensors in clinical environments reflecting typical patient activity. We also derived Signal Quality Indices for identifying motion-corrupted data from which no clinical decisions should be made, and have developed algorithms for extracting respiratory rate from a pulse oximetry finger probe. In the last 12 months, we have set up a 150-patient clinical trial at St Thomas’ Hospital for post-surgical monitoring of cardiac surgery patients (bypass or valve replacement) using wireless sensors and hospital wi-fi.