Comparison of visual estimation of intra-operative blood loss with haemoglobin estimation in patients undergoing...

Obstetrical haemorrhage is a potentially preventable cause of maternal morbidity and mortality; and measurements of surgical blood loss (BL) are often inaccurate. Accurate BL estimation is paramount as it may substantially alter the timing of interventions to control haemorrhage. The study compares the assessment of intra-operative BL by visual estimation with BL calculated from haemoglobin estimation using the HemoCue®201+.

A total of 60 pregnant patients at term undergoing elective caesarean section under spinal anaesthesia were enrolled into the study. In the theatre, the patients' haemoglobin level was determined before and after the surgery using the HemoCue®201+; and a modified Gross formula was used to calculate the BL. BL was also visually estimated and documented by counting the blood-soaked abdominal mops and gauze pieces and multiplying them by the estimated volume of blood each would hold; fixed size mops and gauzes were used. Statistical analysis was performed to compare both methods using SPSS Version 17. To compare BL assessment, Pearson's correlation and the Bland and Altman's method of assessing agreement between two methods of clinical measurement were used.

The mean visually estimated BL (EBL) and HemoCue calculated BL (CBL) were 470 ± 221 ml and 563 ± 204 ml, respectively (P = 0.125). The bias (mean difference between both methods) was negligible (45.25 ml), and the limit of agreement between both methods was -222.20-275.43 ml. The discrepancy between the two methods increased when BL was ≥500 ml.

This study showed that visually EBL was closely related to HemoCue CBL when the quantity of BL was <500 ml.