Mike Smyth

Paramedic

United Kingdom

Doctorate Title: Prehospital recognition of sepsis by ambulance clinicians.

Doctorate Description: Context: Prehospital recognition of adult patients with sepsis may inform scene management by ambulance clinicians, improve decisions concerning both appropriate hospital destination and urgency of transport, as well as facilitate early intervention before arriving at hospital.

Objective: To develop a prehospital sepsis screening tool, derived from prehospital data, for use by ambulance clinicians.

Design: The thesis comprises a systematic review of sepsis among adult patients in the prehospital environment, followed by the derivation and validation of a sepsis screening tool, utilising a retrospective data cohort comprising data from West Midlands Ambulance Service (WMAS) and the Emergency Department at University Hospital North Staffordshire (UHNS). This is followed by a comparison with alternate screening tools.

Patients: Consecutive patients transported by WMAS (n=38483) to UHNS between 01 July 2013 and 30 June 2014. Records were linked using LinkPlus® software. Successful linkage was achieved in 33289 cases (86%). Eligible patients included adult, non-trauma, non-mental health, non-cardiac arrest cases. Of 33289 linked cases, 22945 cases were eligible. The eligible cases were randomly divided into derivation (n=16063, 70%) and validation (n=6882, 30%) cohorts.

Outcome Measure: High risk of sepsis, as defined by the 2016 National Institute for Health and Care Excellence (NICE) Sepsis guideline (NG51).

Results: High risk of sepsis was present in 3.7% of both derivation (n=593) and validation (n=254) cohorts. The Screening to Enhance PrehoSpital Identification of Sepsis (SEPSIS) tool is composed of the following variables: age, respiratory rate, peripheral oxygen saturations, heart rate, systolic blood pressure, temperature and level of consciousness (p<0.001 for all variables). Area under the receiver operating characteristic curve was 0.87 (95%CI 0.85-0.88) for the derivation cohort, and 0.86 (95%CI 0.84-0.88) for the validation cohort. Applying a cut-off of 3 or higher, sensitivity for the SEPSIS screening tool was 0.80 (95%CI 0.74-0.84), specificity was 0.78 (95%CI 0.77-0.79), positive predictive value was 0.12 (95%CI 0.10-0.14), negative predictive value was 0.99 (95%CI 0.99-0.99), positive likelihood ratio was 3.56 (95%CI 3.30-3.85), negative likelihood ratio was 0.26 (95%CI 0.21-0.34) and the diagnostic odds ratio was 13.5 (95%CI 9.9-18.4).

Conclusion: The SEPSIS screening tool was significantly associated with high risk of sepsis status on arrival at the Emergency Department. It performs marginally better than both the UK Sepsis Trust “Red Flag” algorithm and National Early Warning Score (NEWS≥5) in an undifferentiated, adult, medical population. The SEPSIS screening tool requires external validation, in clinical practice by ambulance clinicians, in an independent population.