Visual estimation of blood loss by UK pre-hospital clinicians: an observational study

To assess the accuracy of visual estimation of external blood loss by UK pre-hospital clinicians and to comment on its value during handover.

A sample of 104 pre-hospital clinicians were shown eight staged scenarios showing varying amounts of blood loss and asked to estimate the amount of blood loss depicted. Participants included a range of pre-hospital clinicians from both NHS ambulance trusts and Helicopter Emergency Medical Services.

A wide distribution of estimates and therefore percentage error was observed in our study. Pre-hospital clinicians are inaccurate when estimating external blood loss at scene, regardless of training and skill level.

Visual estimation of blood loss is too inaccurate to be considered clinically worthwhile. Greater research focus is needed to investigate and validate better measures of blood loss that can be utilised in the pre-hospital and emergency medicine environment. Until evidence-based methods of estimation can be implemented, this information should not be included in hospital handovers.