The Center for Disaster Medicine and Traumatology

National Research Center for Traumatology assigned by the Swedish National Board of Health and Welfare

Perception of blood loss – what’s bad and what’s not

How laypeople perceive bleeding and bleeding severity may affect both the first aid provided, and how different first aid and bleeding control training programs are developed. Researchers at KMC and Old Dominion University investigated laypeople perception of bleeding in a controlled experimental study. The participants viewed a series of short videos of simulated bleeding and proceeded to make different estimations. They were asked to assess the severity of the bleeding, how long the person had left until death occurs, and which first aid measure to stop the bleed they opted for.  

“We have developed a useful methodology to study laypeople’s perception of bleedings, where single parameters can be adjusted in a controlled manner”, says Erik Prytz, senior lecturer at Linköping University and senior researcher at KMC.  

Erik Prytz, senior lecturer

The results show that laypeople hold misconceptions, for example on how long a bleeding can continue until it becomes life-threatening. The study also shows a difference between genders in which first aid measures were chosen, where participants recommended using a tourniquet at lower blood loss volumes for the male actor than the female one in the videos.  

“The results are valuable for further development of first-aid training programs. To be able to adjust training and education to the needs of laypeople and medical professionals, we need to be aware of different misconceptions laypeople may hold on e.g. severity of blood loss.” 

Future research will investigate more variables that can affect laypeople’s perception of blood loss, both to develop research methodology and bleeding control training programs.   

Prytz, E., Phillips, R., Lönnqvist, S., Friberg M., Jonson , C-O. 
Laypeople perception and interpretation of simulated life-threatening bleeding:
a controlled experimental study. 

BMC Emerg Med 21, 100 (2021).  


Read more on Stop the Bleed-research at KMC