JMIR Publications

ABSTRACT

Background:

Early Warning Scores (EWS) are routinely used in hospitals to assess a patient’s risk of deterioration. EWS are traditionally recorded on paper observation charts but are increasingly recorded digitally. In either case, evidence for the clinical effectiveness of such scores is mixed, and previous studies have not considered whether EWS lead to changes in how deteriorating patients are managed.

Objective:

We examine whether the introduction of a digital Early Warning Score (EWS) system was associated with more frequent observation of patients with abnormal vital signs, a precursor to earlier clinical intervention.

Methods:

We conducted a two-armed stepped-wedge study from February 2015-December 2016, over four hospitals in one UK hospital trust. In the control arm, vital signs were recorded using paper observation charts. In the intervention arm, a digital EWS system was used. The primary outcome measure was Time To Next Observation (TTNO), defined as the time between a patient’s first elevated EWS (EWS ≥ 3) and subsequent observations set. Secondary outcomes were time to death in hospital, length of stay, and time to unplanned ICU admission. Differences between the two arms were analysed using a mixed effects Cox model. Usability of the system was assessed using the System Usability Score survey.

Results:

We in¬¬¬¬cluded 12,802 admissions, 1,084 In the paper (control) arm and 11,718 on the digital EWS (intervention) arm. The System Usability Score was 77.6, indicating good usability. The median TTNO in the control and intervention arms were 128 minutes (IQR: 73-218) and 131 minutes (IQR: 73-223), respectively. The corresponding hazard ratio for TTNO was 0.99 (95% CI: 0.91 - 1.07, P = .73).

Conclusions:

We demonstrated strong clinical engagement with the system. We found no difference in any of the pre-defined patient outcomes, suggesting introduction of a highly usable electronic system can be achieved without impacting clinical care. Our findings contrast with previous claims that digital EWS systems are associated with improvement in clinical outcomes. Future research should investigate how digital EWS systems can be integrated with new clinical pathways adjusting staff behaviours to improve patient outcomes.