New Method Allows EMTs to More Accurately Estimate Blood Loss at Trauma Scenes

Researchers at UMDNJ-Robert Wood Johnson Medical School have developed a method for quickly determining volume of blood loss that is more accurate than the visual estimates currently used by many emergency medical technicians.

According to a press release from UMDNJ-Robert Wood Johnson Medical School, Mark Merlin, MD, assistant professor of emergency medicine and pediatrics at the UMDNJ-Robert Wood Johnson Medical School and medical director of emergency medical services at Robert Wood Johnson University Hospital, and colleagues have developed the MAR Method, which can be used to estimate the blood volume by counting how many of the estimator’s closed fists it would take to cover the surface area of the blood lost by the victim.

Merlin and colleagues designed a clinical trial to test the MAR method that “compared the anterior (palm side) surface of the fist to the surface area of blood present and created a formula averaging blood per fist,” concluding that a fist “covers a surface area of blood that equals roughly 20 mL.”

The trial involved 78 participants who were asked to estimate two blood volumes (75 mL and 750 mL), first by making a visual assessment and then by using the MAR Method. Participants “got as close to the blood pool as possible and estimate the blood volume by counting how many fists it would take to cover the blood pool.”

According to results published in the American Journal of Emergency Medicine, “After less than one minute of instruction, participants were able to determine blood volumes with improved accuracy and precision.”

Additional Resources

Method of Grant and Reeve for Estimating Blood Loss in Severe Injury This system is “based on the number of the examiner's hands that can be used to cover each of the patient's wounds. While it was developed based on war wounds during World War II, it can be applied to severe civilian traumatic injury.”

Method of Maull for Estimating Blood Loss with Severe Trauma This page offers “presented several heuristics for estimating blood loss in a patient after severe trauma.”

Estimation of External Blood Loss by Paramedics: Is There Any Point?

Presents results from a study designed to “determine if undergraduate paramedic students could accurately estimate external blood loss on four surfaces commonly found in the prehospital environment.” The authors conclude that “External blood loss estimation by undergraduate paramedic students generally is too inaccurate to be of any clinical benefit. Particularly, absorbent and impermeable surfaces precipitated inaccuracies by undergraduate paramedic students.”