Comparison of common perioperative blood loss estimation techniques: a systematic review and meta-analysis

Abstract

Estimating intraoperative blood loss is one of the daily challenges for clinicians. Despite the knowledge of the inaccuracy of visual estimation by anaesthetists and surgeons, this is still the mainstay to estimate surgical blood loss. This review aims at highlighting the strengths and weaknesses of currently used measurement methods. A systematic review of studies on estimation of blood loss was carried out. Studies were included investigating the accuracy of techniques for quantifying blood loss in vivo and in vitro. We excluded nonhuman trials and studies using only monitoring parameters to estimate blood loss. A meta-analysis was performed to evaluate systematic measurement errors of the different methods. Only studies that were compared with a validated reference e.g. Haemoglobin extraction assay were included. 90 studies met the inclusion criteria for systematic review and were analyzed. Six studies were included in the meta-analysis, as only these were conducted with a validated reference. The mixed effect meta-analysis showed the highest correlation to the reference for colorimetric methods (0.93 95% CI 0.91–0.96), followed by gravimetric (0.77 95% CI 0.61–0.93) and finally visual methods (0.61 95% CI 0.40–0.82). The bias for estimated blood loss (ml) was lowest for colorimetric methods (57.59 95% CI 23.88–91.3) compared to the reference, followed by gravimetric (326.36 95% CI 201.65–450.86) and visual methods (456.51 95% CI 395.19–517.83). Of the many studies included, only a few were compared with a validated reference. The majority of the studies chose known imprecise procedures as the method of comparison. Colorimetric methods offer the highest degree of accuracy in blood loss estimation. Systems that use colorimetric techniques have a significant advantage in the real-time assessment of blood loss.

The visually estimated blood volume in scaled canisters based on a simulation study

“…In a meta-analysis [2] on the techniques of intraoperative blood loss recording by our research group, Fig. 7 Scatter plots with corresponding regression lines for canisters Scatter plots for visually estimated blood loss (V-EBL) for canisters and corresponding univariate linear regression line as a function of reference blood loss (RBL) Fig.…”

“…For the experimental setup, expired or unusable whole blood donations (provided by the German Red Cross, Institute for Transfusion Medicine, Goethe University Frankfurt, Germany) were diluted with whole electrolyte solutions (Sterofundin ISO, B. Braun, Melsungen, Germany) to generate predetermined volumes (188 ml-1267 ml) with defined hemoglobin (Hb) values (9.5-12.1 g/ dl). The use of whole blood donations is a well-established method for the experimental determination of blood loss [2]. The prepared mixture was set as the reference blood loss (RBL).…”

“…This does not only include the estimation of blood volume in surgical drapes and suction canisters, but also the recording of external blood loss. However, it is known that this method is associated with systematic errors (underor overestimation of blood loss) depending on the person making the estimation [2,3]. In every operating room you will find scaled suction canisters that collect fluids from the surgical field.…”

Delivery method of the placenta in cesarean deliveries and the effect of uterine incision repair area on morbidity: A randomized controlled study

“…There are many approaches to establishing the quantity of blood loss during cesarean section ( 8 ) . The American College of Obstetricians and Gynecologists authorizes the meaningful recommendations and concerns.…”

Measurement of Intraoperative Blood Loss in Minimally Invasive Neurosurgery

“…This method involved the use of a meticulous measurement technique carried out within the best conditions for the measurement of blood loss. All blood loss formulae have similar structures and bases [21,[28][29][30]. A euvolemic state between the pre and postoperative times is assumed.…”