Validation of the pre-hospital Qatar Early Warning Score (QEWS) to determine transport priority

Background: Ambulance Paramedics are dispatched to all calls while Critical Care Paramedic (CCP) units only attend potentially “life threatening” cases (Priority 1). Ambulance Paramedics (AP) triaged patients based on clinical judgment and experience creating a risk of Priority 1 under or over-triage. QEWS was designed to supplement priority decision-making process based on physiological values used as a trigger to identify patients with a potential risk of deterioration. The objective of this study was to undertake a comparison of the QEWS score calculated from retrospective vital signs data to that of the priority decision-making by ambulance crews.

Methods: In our retrospective study, data entered into the Ambulance Service clinical database over a nine-month period before QEWS implementation was analysed for comparison of the priority decision made by the crew for each patient versus the calculated QEWS value based on the first set of six relevant vital signs (Heart rate, Respiratory rate, Systolic blood pressure, Temperature, Oxygen saturation, AVPU). Only cases with patients over 18 years old were included.

Results: Of 34,908 retrieved cases, 27,915 (79.97%) had sufficient data to retrospectively determine QEWS. The mean age was 38.62 (þ15.84) years and 21,453 (76.85%) were male patients. Priority decision-making correlated in 25,850 cases (92.6%), with 286 (1.11%) Priority 1 and 25,564 (98.89%) Priority 2 patients. In 1,662 cases (5.95%), QEWS retrospectively triaged patients higher and in 1.44%, QEWS triaged patients lower.

Conclusions: Physiological variables are an established predictor of risk regarding a patient’s condition. Hospital-based early warning scores have been validated and implemented successfully. Only one published pre-hospital scoring system has been validated for triage. Under-triage appears to be a common problem in medical patients. QEWS potentially could address this under-triage issue and appears to be a valid scoring system to implement for prioritising patients to routine or urgent transport, or CCP intervention.