فهرست نشریات علمی دسترسی آزاد ایران

Background and Objectives: Accurate estimation of intraoperative blood loss is essential for safe perioperative management in spinal surgery. Although visual estimation remains widely practiced due to its simplicity, rapidity, and lack of need for special equipment, it is prone to considerable inaccuracy. These limitations can influence transfusion decisions and postoperative outcomes. Therefore, evaluating more objective yet feasible alternatives, such as gravimetric assessment, is clinically important. This study aimed to compare the accuracy of visual estimation and the gravimetric method in assessing intraoperative blood loss and to evaluate their correlation with the reduction in hemoglobin levels 24 hours after surgery.    Methods: In this diagnostic study, 75 adults scheduled for posterior spinal surgery were randomly assigned using a computer‑generated sequence. Visual estimation was performed by blinded surgical staff based on suction volumes and soaked materials, while gravimetric measurement was conducted by weighing blood‑soaked sponges and suction canisters before and after use. The actual blood loss reference was defined as the postoperative hemoglobin decline measured 24 hours after surgery. Accuracy of each method was evaluated by comparing estimated blood loss against this reference standard using appropriate statistical tests.   Results: Among patients with postoperative hemoglobin < 12 g/dL, the mean estimated blood loss was 721.5 ± 556.5 mL by visual estimation and 844.5 ± 704.3 mL by the gravimetric method. For those with hemoglobin ≥ 12 g/dL, respective values were 321.8 ± 282.1 mL and 337.9 ± 286.1 mL. The gravimetric approach estimated on average 72 mL higher blood loss than the visual method (mean difference = 72 mL; 95% CI: 21–123 mL; P < 0.001). Diagnostic indices confirmed the superior accuracy of the gravimetric technique (LR⁺ = 2.04, LR⁻ = 0.42, AUC = 0.81), showing improved discrimination of clinically significant intraoperative bleeding compared with visual estimation.    Conclusion: The gravimetric method provides a more accurate and reliable estimation of intraoperative blood loss compared to visual assessment. Its implementation in spinal surgery could improve patient monitoring and support more informed clinical decision‑making. However, further studies with larger, multicenter cohorts are warranted to validate and generalize these findings.