Since it has remained virtually constant between the different dimensions of blood loss, potential sources of distortion may have been incomplete measurements of blood loss, blood clotting before reaching the aspiration system or blood loss resulting from blood extractions (used for laboratory analyses), although an intrinsic imprecision of the formula cannot be excluded. In our meta-analysis, we were able to show that the estimation of colorimetric blood provides a strong correlation with the reference blood volume. In contrast, the gravimetric method or visual estimation shows only an average correlation. It turned out that the distortion of blood loss in the colorimetric system is significantly lower than for other methods. Torella F, Cowley RD, Thorniley MS, McCollum CN. Regional tissue oxygenation in case of bleeding: can near infrarot spectroscopy be used to monitor blood loss? Shock. 2002;18:440–4. doi.org/10.1097/00024382-200211000-00009. This study established that estimating hemoglobin mass loss was a more accurate method for estimating perioperative blood loss. This estimation method could be a robust research tool, although further studies are needed to determine its reliability. Bias is represented by a crossed gray line, 95% of match boundaries are displayed by dotted black lines, and the equality line is displayed by a dotted gray line. The hemoglobin (A) mass loss formula showed considerable consistency, as estimates tightened with increased blood loss.
In contrast, the López Picado formula (B) and the empirical volume formula (C) did not show consistency, as the propagation width remained unchanged as blood loss intensified. SD: standard deviation. Adkins AR, Lee D, Woody DJ, White WA. .