Blood loss estimation by out-of-hospital emergency care providers

To evaluate emergency medical technicians' (EMTs') ability to estimate spilled blood volume and to determine whether limited training improves estimate accuracy and whether there is a difference in improvement comparing two different training methods.

The study design was a single-blinded, clinical model, utilizing EMTs (basic, intermediate, and advanced) from a local commercial ambulance service. Participants estimated the volume of randomly selected volumes of packed red blood cells reconstituted to a normal hematocrit and poured onto three absorbent (carpet) and three nonabsorbent (vinyl) surfaces. Participants were then randomly assigned to one of two teaching groups. The SITEGRP (n = 17) returned to the six testing sites and were told the actual blood volumes. The SLIDE-GRP (n = 16) were taught with slides of six similar blood spill sites. Both groups were provided with suggestions for making volume estimates. The same participants were then retested one month later using the same type of sites and six new blood volumes.

Thirty-three participants with an average of 7.5 years of prehospital care experience completed testing on both dates. Mean percent error {[(estimated volume - actual volume)/actual volume] x 100} for all participants decreased from 65%+/-33% initially to 52%+/-20% after retesting (p < 0.05). Mean percent error was 74%+/-41% and 59%+/-20% for the SITEGRP (p < 0.15) initially and after retesting, respectively. Mean percent error was 56%+/-17% and 45%+/-17% for the SLIDEGRP (p < 0.05) initially and after retesting, respectively.

Prehospital care providers are not accurate at estimating spilled blood volumes. This ability can be improved with limited education. Slides appear to be as effective as viewing actual spill sites.