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2109 Prehospital early warning scores for adults with suspected sepsis: retrospective diagnostic cohort study
  1. Steve Goodacre1,
  2. Laura Sutton1,
  3. Olivia Hawksworth1,
  4. Khurram Iftikhar2,
  5. Susan Croft2,
  6. Gordon Fuller1,
  7. Mark Millins3,
  8. Simon Waterhouse1
  1. 1University of Sheffield
  2. 2Sheffield Teaching Hospitals NHS Trust
  3. 3Yorkshire Ambulance Service


Aims and Objectives Ambulance services need to identify and prioritise patients with sepsis for early hospital assessment. We aimed to determine the accuracy of early warning scores alongside paramedic diagnostic impression to identify sepsis requiring urgent treatment.

Method and Design We undertook a retrospective diagnostic cohort study involving adult medical cases transported to hospital by emergency ambulance in 2019. We used routine ambulance service data to calculate 21 early warning scores and categorise paramedic diagnostic impressions as sepsis, infection, nonspecific presentation, or other presentation. We linked cases to hospital records and identified those meeting the sepsis-3 definition who received urgent treatment for sepsis (reference standard). Analysis determined the accuracy of strategies that combined early warning scores at varying thresholds for positivity with paramedic diagnostic impression.

Results and Conclusion We linked 12870/24955 (51.6%) cases and identified 348/12870 (2.7%) with a positive reference standard. None of the strategies provided high sensitivity (>0.80) with acceptable positive predictive value (>0.15). The National Early Warning Score, version 2 (NEWS2) provided combinations of sensitivity and specificity that were similar or superior to all other early warning scores. The area under the receiver operating characteristic curve for NEWS2 applied to patients with a diagnostic impression of sepsis or infection was 0.756 (95% confidence interval [CI] 0.729 to 0.783). NEWS2 thresholds of >4, >6 and >8 applied to patients with a diagnostic impression of sepsis or infection respectively provided sensitivities and positive predictive values (95% CI) of 0.522 (0.469 to 0.574) and 0.216 (0.189 to 0.245), 0.447 (0.395 to 0.499) and 0.274 (0.239 to 0.313), and 0.314 (0.268 to 0.365) and 0.333 (CI 0.284 to 0.386).

No strategy is ideal but using NEWS2 alongside paramedic diagnostic impression of infection or sepsis could identify one third to half of sepsis cases without prioritising unmanageable numbers. No other score provided clearly superior accuracy to NEWS2.

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