How do you estimate blood loss on scene?
Did you learn how to do this in coursework, training? Is it something you’ve learned with years of experience? How do you visually estimate it on a shirt or pair of jeans compared to a tile floor? Would your approximation be subjectively higher in a pale, diaphoretic, hypotensive patient? Accurate estimation of external blood loss in traumatic injury is imperative information for appropriate treatment of the trauma patient.
Studies assessing accuracy of external blood loss volume suggest that years of clinical exposure, differing training programs, skill sets, gender or age have very limited effect on precise estimation.4 Multiple observational studies simulated scenes of blood loss with synthetic blood on varying surfaces.1,4,5 Non-porous surfaces (vinyl floor, concrete) were compared to absorbent surfaces such as clothing or carpet. Results were generalized to support prior studies with overestimates on small volumes (less than 150ml) and underestimates on large. Specific trends highlighted overestimating on clothing and underestimating on carpet.3
Further research needs to be completed on this topic as there is no formal training to accurately estimate blood volume loss. There has been discussion of a visual instructional session with images and amounts as well as the MAR Method, both studied using only non-porous surfaces. The MAR Method, although still being researched, has shown significant improvements in accuracy and precision in estimating volume loss. “This method utilizes your clenched fist to estimate blood volumes. The volume of a blood pool depends on how many fists it would take to cover the pool. One fist equals 20mls of blood. So, if it takes 3 fists to cover a blood pool. Which equals 60mls of blood”.2 This is similar to the palmer method of burn estimation; using the patient’s palm and fingers to approximate one percent of total body surface area.
Due to inaccuracies and limited standardized teaching, there are suggestions to depreciate blood loss estimation and focus on hemodynamic stability alone. One argues that the team caring for pediatric or geriatric patients with limited compensatory mechanisms or those on medications with multiple comorbidities affecting vital signs will clinically value the estimation.
Try your hand at estimating via the display bulletin board at IU Health Methodist across from the EMS break room.
References
1Frank, M. Schmucker, U. Stengel, D., Fischer, L., Lange, J., Grossjohann, R., Ekkernkamp, A., & Matthes, G. (2010). Proper estimation of blood loss on scene of trauma: Tool or tale? The Journal of Trauma: Injury, Infection, and Critical Care, 69 (5), 1191-1195.
2 Merlin, M.A., Alter, S.M., Raffel, B., & Pryor, P.W. (2008). External blood loss estimation using the MAR Method. The American Journal of Emergency Medicine, 27, 1085-1090.
3 Strote, J., Mayo, M., & Townes, D. (2008). ED patient estimation of blood loss. The American Journal of Emergency Medicine, 27, 709-711.
4 Tall, G., Wise, D., Grove, P., Wilkinson, C. (2003). The accuracy of external blood loss estimation by ambulance and hospital personnel. Emergency Medicine, 15, 318-321.
5 William, B. & Boyle, M. (2007). Estimation of external blood loss by paramedics: Is there any point? Prehospital and Disaster Medicine, 22 (6), 502-506.
Image from http://zeds-stock.deviantart.com/art/Bloody-Hand-Prints-Brush-Pack-134526043#/art/Blood-Spatter-131001332?_sid=2071a527>