Analysis of the estimation of bleeding using several proposed haematometric equations.

PURPOSE: Among various methods for estimating blood loss, the gravimetric method is the most accurate; however, its use in routine practice is complicated. Although several equations have been proposed for this purpose, there is no consensus on the most suitable. METHODS: A cross-sectional study was conducted in seven secondary and tertiary hospitals between March and July 2018 including all patients undergoing total hip arthroplasty or hip prosthesis replacement under general or regional anaesthesia. We compared blood loss estimates obtained using the gravimetric method (weighing gauzes and pads and measuring volumes of blood collected by suction during surgery) and using three different equations, two of which considered intravenous fluids (CRYS 3.5 and 1.5) and a third which did not (the traditional equation). Additionally, intraclass correlation coefficients (ICCs) and Bland-Altman plots were used. RESULTS: The mean blood loss estimated using the gravimetric method was 513.7 ± 421.7 mL, while estimates calculated using the CRYS 3.5, CRYS 1.5 and traditional equations were 737.2 ± 627.4, 420.8 ± 636.2 and 603.4 ± 386.3 mL, respectively. Comparing these results, we found low levels of agreement (based on ICCs), except when using the traditional equation (ICC: 0.517). The limits of agreement comparing external blood loss with the estimates from the equations ranged from - 1655.6 to 1459.2 in the case of the CRYS 1.5 equation to - 839.6 to 1008.4 in the case of the traditional equation. CONCLUSIONS: For use in clinical practice, haematological index-based equations, regardless of whether they consider fluids administered, do not show sufficiently strong correlations with gravimetric estimates of intraoperative blood loss.

Tranexamic Acid Compared with Placebo for Reducing Total Blood Loss in Hip Replacement Surgery: A Randomized Clinical Trial.

BACKGROUND: Tranexamic acid (TXA) reduces bleeding in patients undergoing hip replacement surgery, but optimal doses and timing have yet to be established. Our primary objective in this study was to assess total blood loss 48 hours after surgery with different regimens. METHODS: This was a multicenter, parallel-group, randomized, placebo-controlled clinical trial that included all ASA physical status I to III patients undergoing unilateral total hip replacement surgery who met the inclusion criteria. Patients were randomly allocated to 1 of 3 groups: a single-dose group (15 mg/kg TXA before the start of surgery and saline 3 hours later after the start of surgery), a 2-dose group (10 m/kg TXA before and 10 mg/kg of TXA 3 hours after the start of surgery), and a control group (saline before and 3 hours after the start of surgery). Total blood loss was calculated using a formula considering hematocrit values and blood transfusions received. RESULTS: We included 108 patients in the study. Total blood loss volumes up to day 2 were 1377 ± 689, 1308 ± 641, and 2215 ± 1136 mL in the single-dose, 2-dose and control groups, respectively (P < 0.001 between the placebo and the experimental groups). Blood transfusions were given to 22.9% of patients (n = 8) in the single-dose group, 11.1% (n = 4) in the 2-dose group, and 37.8% (n = 14) in the control group (P = 0.028). CONCLUSIONS: A single preoperative dose of TXA or 2 infusions of a lower dose, preoperatively and then after 3 hours after the start of surgery, resulted in lower blood loss during the first 2 days after surgery and less need for blood transfusion, with good levels of safety.