Background: Particularly for protracted bleeding situations, the realization of a relevant blood loss is necessary for early initiation of therapy to avoid hemodynamic instability and shock. The frequently used visual assessment of blood loss is known to be incorrect. An innovative option to address this problem is a mobile application using colorimetric image correction and analysis.
Methods: The objective of this study was to evaluate the clinical applicability and accuracy of a novel mobile device application using colorimetric image correction and analysis for blood loss estimation. Scenarios of blood-filled surgical sponges were created to evaluate the accuracy of colorimetric-based blood loss estimation and visual and gravimetric blood loss estimation.
Results: Fifty-three anesthesiologists ran through the scenarios. The estimated blood loss correlated the least with the reference blood loss in the visual technique (Rho: 0.52; P < 3.7×10-16), followed by the gravimetric technique (Rho: 0.73; P = 2.8×10-05). The best correlation was found in the colorimetric blood loss measurement (Rho: 0.77; P = 3.53×10-06). A median overestimation per scenario of 133.0 mL (interquartile range [IQR] 33.0 mL-283.0 mL) was observed when using the visual method, whereas 32.5 mL (IQR 10.8 mL-44.0 mL) was overestimated with the gravimetric method and 31 mL (IQR 17.0 mL-42.8 mL) with the colorimetric method. Especially in the case of blood loss underestimation, the application has the least deviation from the reference.
Conclusion: The blood loss measured in the sponges correlated strong with the reference blood loss, showing the smallest median overestimation and the smallest deviation in underestimation. The visual estimation shows serious errors, where the gravimetric method is prone to errors, especially in dilution. The colorimetric method offers an easily implementable possibility to monitor blood loss in real time and to initiate early diagnostic and therapeutic measures in case of persistent blood loss. The influence of real-time estimation of colorimetric blood loss on transfusion decisions should be the subject of future studies.
Trial registration: ClinicalTrials.gov NCT04245995.
Copyright © 2020 by the Shock Society.