Accuracy of Blood Loss Measurement during Cesarean Delivery

Abstract

Objective This study aims to compare the accuracy of visual, quantitative gravimetric, and colorimetric methods used to determine blood loss during cesarean delivery procedures employing a hemoglobin extraction assay as the reference standard. Study Design In 50 patients having cesarean deliveries blood loss determined by assays of hemoglobin content on surgical sponges and in suction canisters was compared with obstetricians' visual estimates, a quantitative gravimetric method, and the blood loss determined by a novel colorimetric system. Agreement between the reference assay and other measures was evaluated by the Bland–Altman method. Results Compared with the blood loss measured by the reference assay (470 ± 296 mL), the colorimetric system (572 ± 334 mL) was more accurate than either visual estimation (928 ± 261 mL) or gravimetric measurement (822 ± 489 mL). The correlation between the assay method and the colorimetric system was more predictive (standardized coefficient = 0.951, adjusted R2 = 0.902) than either visual estimation (standardized coefficient = 0.700, adjusted R2 = 00.479) or the gravimetric determination (standardized coefficient = 0.564, adjusted R2 = 0.304). Conclusion During cesarean delivery, measuring blood loss using colorimetric image analysis is superior to visual estimation and a gravimetric method. Implementation of colorimetric analysis may enhance the ability of management protocols to improve clinical outcomes.

Effect of Implementing Quantitative Blood Loss Assessment at the Time of Delivery

“…This is similar to the findings by Doctorvaladan et al who compared a hemoglobin content assay with visual, gravimetric, and colorimetric blood loss during 50 CDs. 16 This study found that the visual EBL correlated better with the hemoglobin assay than the gravimetric measured blood loss. Our study supports the findings of these authors and further suggests EBL has a higher sensitivity and specificity for predicting postpartum blood product transfusion than qBL, raising concerns that implementation of qBL may increase the rate of PPH and unnecessary transfusions.…”

“…This unique aspect of the current study differentiates it from previously published studies on EBL and qBL. 16,17 Hamm et al compared EBL and qBL in all deliveries, regardless of mode of delivery or amount of blood loss, to predict a change in hemoglobin and also concluded that qBL does not predict a change in hemoglobin more accurately than EBL. Hamm et al examined a subgroup of women in this study with PPH (defined by ACOG revitalize, >1,000 mL regardless of mode of delivery).…”

Implementing Delayed Umbilical Cord Clamping in Cesarean Birth Using a Novel Method: A Pilot Study of Feasibility and Safety

“…31 Colorimetric image analysis is another option that is relatively new but in studies appears superior to both visual EBL and quantified blood loss in cesarean birth. 32,33…”

Accurate Assessment of Blood Loss during Cesarean Delivery Improves Estimation of Postoperative Hemoglobin

“…Lilley et al 22 concluded that in a mixed group of vaginal and cesarean deliveries, gravimetric assessment of blood loss during PPH was effective, while Johar and Smith 21 determined that in surgical procedures, the technique was frequently inaccurate due to issues such as recording bias, amniotic fluid/saline corruption, and human error. The presence of amniotic fluid in canisters and on soiled sponges was also shown to confound this method as described by Doctorvaladan et al 26 In practice, the quantitative gravimetric method has proven cumbersome and adoption has been poor. 21,22,34 The formula used to predict postoperative hemoglobin is logical and was consistently applied but does not account for the changes in blood volume as discussed earlier.…”

“…The performance of the device has been validated in bench-top and clinical settings. [23][24][25][26][27] Accurate blood loss measurements using the novel device are known to be a better predictor of postoperative hemoglobin levels than visually estimated blood loss in patients having burn and other wound excisions. 28 While recognizing the limits of the hemoglobin concentration to guide transfusion decisions, we hypothesized that accurate blood loss determinations could improve the prediction of postoperative hemoglobin levels in cesarean delivery patients potentially leading to improved transfusion practice and overall patient management.…”