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752 External validation of a novel TRIP (Cast) score to identify patients at risk of venous thromboembolism after temporary immobilisation for lower limb injury
  1. Daniel Horner1,
  2. Stephanie Howard2,
  3. Michael Campbell2,
  4. James Collins2
  1. 1Salford Royal Hospital
  2. 2Salford Royal NHS Foundation Trust


Aims/Objectives/Background Temporary immobilisation after lower limb injury incurs a significant risk of venous thromboembolism (VTE). These events are potentially preventable through patient education and risk based pharmacological thromboprophylaxis. Recent evidence has identified a potentially optimal risk assessment model, the TRIP (cast) score. We sought to evaluate the potential impact of implementation within a UK Emergency Department (ED).

Methods/Design A retrospective cohort study, using prospectively collected routine data accessible through electronic health records. All ED patients with temporary lower limb immobilisation and documented VTE risk assessment during 2019 were included. TRIP (cast) scores were calculated retrospectively. Rapid case note review was undertaken to identify VTE, bleeding and mortality events up to 90 days post discharge. The project was formally approved as a service evaluation and had R&D oversight throughout (Ref: S21HIP25).

Abstract 752 Figure 1

Type of immobilisation applied (N=520)

Abstract 752 Figure 2

Diagnostic coding data (N=520)

Abstract 752 Figure 3

Frequency histogram of TRIP (Cast) scores (N=520)

Results/Conclusions We identified 670 relevant ED patients with lower limb injury. We excluded all subsequent hospital admissions and patients already established on anticoagulation. 520 patients were included in the final dataset, with a mean age of 40.7 (SD 17.1) and a median ED stay of 170 minutes. Discharge diagnoses and immobilisation method are shown in figures 1 and 2.

89 (17.0%) patients were offered pharmacological thromboprophylaxis. No VTE events were recorded in this group. However, in 435 (83%) patients who did not receive prophylaxis, 5 VTE events were recorded, including 3 proximal thrombi. We found no evidence of major or clinically relevant non-major bleeding.

A frequency histogram of derived TRIP (Cast) score values is shown in figure 3. A threshold of ³6 for prophylaxis would result in 111 (21.1%) patients being offered prophylaxis, with all 3 of the proximal VTE events potentially prevented.

In conclusion, use of the TRIP (Cast) score in our ED population appears to outperform current risk assessment practice, at a small overall increase in the population eligible for prophylaxis.

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