A randomised controlled trial of verbal guidance versus verbal guidance supplemented by a photographic aid for bystander identification of intramuscular tranexamic acid injection sites in a simulated road injury scenario

Background: Non-compressible haemorrhage is a leading cause of preventable death following road injury. Tranexamic acid (TXA), when administered early, improves survival. Intramuscular (IM) administration offers a feasible route for early administration by lay bystanders. However, the ability of bystanders to correctly identify safe IM injection sites remains unclear. This study aimed to evaluate whether verbal guidance supplemented by a photographic aid improves the accuracy of site identification in a simulated road injury scenario. Methods: In this randomised controlled trial, 64 lay participants were recruited on a university campus and randomised to receive either (1) verbal guidance alone or (2) verbal guidance plus photographic aid to locate the deltoid injection site on a simulated injured person. Site identification was assessed via sticker placement, and three expert raters with diverse medical backgrounds independently reviewed standardised photographs to determine site safety using a majority agreement rule. The primary outcome was safe site identification. A binomial generalised linear model assessed the association between intervention group and correct site identification. Inter-rater reliability was measured using Fleiss’ Kappa. Results: Participants in the verbal guidance plus photographic aid group were significantly more likely to identify a safe injection site compared to those receiving verbal guidance alone (87.5% vs. 62.5%; OR 4.67, 95% CI 1.33, 19.92, p = 0.03). The presence of concerns regarding site safety was also significantly lower in the photo and verbal group (18.8% vs. 53.1%, p = 0.002). No significant associations were found between accuracy and participant age, gender, prior training, or confidence. Conclusions: Supplementing verbal guidance with a photographic aid significantly improves bystander accuracy in identifying safe IM TXA injection sites in a simulated setting. This finding supports the potential integration of visual aids into emergency dispatch protocols to enhance early haemorrhage control in trauma care. Further research is needed to assess real-world application and impact. Clinical trial number: ISRCTN Registry: ISRCTN41280918. Trial registration: ISRCTN Registry: ISRCTN41280918, 08/08/2025 Retrospectively registered.