Randomised controlled trial comparing marksmanship following application of a tourniquet or haemostatic clamp in healthy volunteers

Background: In a care under fire situation, a first line response to haemorrhage is to apply a tourniquet and return fire. However, there is little understanding of how tourniquets and other haemorrhage control devices impact marksmanship.

Methods: We compared the impact of the iTClamp and the Combat Application Tourniquet (CAT) on marksmanship. Following randomisation (iTClamp or CAT), trained marksmen fired an AR15 at a scaled silhouette target in prone unsupported position (shooting task). Subjects then attempted to complete the shooting task at 5, 10, 15, 30 and 60 min post-haemorrhage control device application.

Results: All of the clamp groups (n=7) completed the 60 min shooting task. Five CAT groups (n=6) completed the 5 min shooting task and one completed the 5 and 10 min shooting task before withdrawing. Four CAT groups were stopped due to unsafe handling; two stopped due to pain. When examining hits on mass (HOM) for the entire shooting task, there was no significant difference between tourniquet and iTClamp HOM at 5 min (p=0.18). However, there was a significant difference at 10 min, p=0.003 with tourniquet having significantly fewer HOM (1.7±2.7 HOM) than the iTClamp (8.1±3.3 HOM) group. The total effective HOM for the entire 60 min shooting task showed that the iTClamp group achieved significantly (p=0.001) more HOM than the tourniquet group. Over the entire 60 min shooting exercise, the iTClamp group achieved a median 72% (52/72) of available HOM while the tourniquet group obtained 19% (14/72).

Conclusions: Application of a tourniquet to the dominant arm negates effective return of fire in a care under fire setting after a brief time window. Haemorrhage control devices that preserve function may have a role in care under fire situations, as preserving effectiveness in returning fire has obvious operational merits.