Effective haemorrhage control is crucial in cases of limb trauma involving arterial injury, such as shark attacks, to prevent potentially fatal outcomes. International first aid consensus recommends the use of arterial tourniquets (proprietary or makeshift) as a primary treatment for life-threatening external bleeding. Manual pressure applied directly over a major artery proximal to the injury, such as inguinal fist compression (IFC), is more accessible in a first-aid situation, but is currently not recommended due to limited evidence. The purpose of this study is to determine whether the application of IFC is superior to commercial windlass tourniquets (CWTs) in reducing blood flow in the femoral artery when performed by untrained bystanders.

Stopping Haemorrhage by Application of Randomised Compression or Tourniquet (SHARC-2) is a superiority, assessor-blinded, cross-over, randomised controlled trial conducted with healthy untrained adult volunteers in non-clinical settings. Participants will be rotated as providers and recipients of both IFC and CWT, with providers randomised to the order that they perform the techniques. Providers will be exposed to an educational infographic before applying that technique to a recipient behind a drop sheet. A sonographer, blinded to the technique, will measure the peak systolic velocity of blood flow in the superficial femoral artery using Doppler ultrasound at baseline and then during application of each technique for 5 min. The mean percentage reduction in peak systolic velocity will be compared between IFC and CWT groups.

Ethics approval for this study was granted by the Bond University Human Research Ethics Committee (BUHREC JF01036) on 23 January 2023. All participants will be provided with written informed consent prior to enrolment and the trial will involve healthy adult volunteers. To minimise risk, preintervention screening, sonographic assessment and postintervention follow-up will be implemented with adverse events monitored and reported in accordance with HREC guidelines. Results will be disseminated through peer-reviewed journals, academic conferences, local resuscitation forums and public health education initiatives. A lay summary will also be shared with relevant community groups and via social media platforms to enhance public accessibility.

ACTRN12624001054505.