Early warning scores, based on the vital signs of a patient signs (blood pressure, heart rate, breathing rate, oxygen saturation and temperature) are designed to facilitate recognition of deteriorating patients in hospital. Each vital sign is assigned a score, which increases as the vital sign becomes more abnormal. The score for each vital sign is then summed to provide an aggregate score. However, the early warning scores in use in 2010 were predominately based on clinician expertise rather than being developed from high quality data.
However, paper-based systems – the traditional chart at the end of the bed – have several flaws. Errors in both assignment and summation of scores result in missed opportunities to recognise patient deterioration early. Assignment and summation also takes additional time, which could be better spent caring for the patient. It also takes up chart space, decreasing the readability of the chart.
The BRC therefore supported the development of the System for Electronic Notes Documentation (SEND), designed to be an ergonomic and efficient electronic early warning scoring system where real-time data is shared, whilst minimising recording errors using tablet computers. In 2011 the Oxford Biomedical Research Centre (BRC) supported the development of an evidence-based early warning system to identify deteriorating patients in hospital. (Tarassenko L, Clifton DA, Pinsky MR, Hravnak MT, Woods JR, Watkinson PJ. Centile-based early warning scores derived from statistical distributions of vital signs. Resuscitation. 2011 Aug;82(8))
The score assigned to a vital sign is derived from the distributions of over 64,000 hours of patient vital sign data from hospitals in the United Kingdom and in the United States. By using the distributions of these vital signs, the system alerts clinicians to patients who have vital signs in the 12% most abnormal range for at-risk in hospital patients, in line with the original aspirations for early warning scores. This method is substantially different to other systems in current use. Introduction of the early warning system unified the alerting system across all four hospitals within the Oxford University Hospitals NHS Foundation Trust meaning clinicians could view patient data on any tablet within the Trust, saving time and improving patient safety. There was a 10% reduction in cardiac arrest rates in the year following introduction.
Video about the SEND project:
SEND consists of:
- a web-based application for input and display of vital signs and early warning scores, designed with clinicians
- tablet computers and barcode scanners integrated with existing monitoring equipment to minimise staff workload whilst aiding good documentation
- barcode identification of both clinician and patient (NHS number-based)
- “dashboard” applications for rapid personal, ward-level, team-level and hospital-level chart review
- a reporting engine, providing real-time overview of clinical practice quality using National Institute for Health and Care Excellence criteria.
- integration with the hospital’s Integrated Digital Care Record (IDCR), in our case the Electronic Patient Record (EPR) in Cerner Millennium
SEND improves patient care and safety by:
- making deteriorating patients immediately visible to appropriate clinicians (the right patient, to the right clinician, at the right time)
- improving accuracy and speed of data recording
- eliminating errors in early warning score calculation
- prompting and supporting appropriate care for each set of vital signs
- integrating early warning data into the hospital’s IDCR
- supporting clinical governance and safety auditing
The SEND system has been rolled out throughout all the adult wards in the four hospitals of Oxford University Hospitals NHS Foundation Trust, with more than 16m observations already acquired (January 2017). The system was carefully designed to avoid delays in data entry and processing. A pilot study at the John Radcliffe Hospital suggests that SEND reduces the average time to undertake a set of observations by approximately 60 seconds. Because of the large number of observations undertaken each day, over the 65 acute Trust areas, this equates to having an extra 3.5 nurses for each 24-hour period.
As well as improving individual patient care, the SEND system allows information about patients to be shared between the hospitals. This ensures quicker decision-making and allows cross-linking with other patient data. On many wards, patients are now prioritised during the ward round according to their latest risk score.