Quantification and influencing factors of perioperative hidden blood loss during intramedullary fixation for intertrochanteric fractures in the elderly.

<bold>Introduction: </bold>We aimed to quantify perioperative hidden blood loss (HBL) and investigate its influencing factors in elderly patients with intertrochanteric fractures (IFs) undergoing intramedullary fixation surgery.<bold>Materials and Methods: </bold>We prospectively collected the clinical data of 200 elderly patients with IFs treated with intramedullary fixation surgery in our hospital between December 1, 2014 and August 31, 2018. The intraoperative visible blood loss, blood transfusion rate, and pre- and postoperative hemoglobin (Hb) levels as well as the general characteristics of the enrolled patients were recorded. A multiple linear regression analysis model (stepwise) was used to identify independent factors affecting perioperative HBL.<bold>Results: </bold>The mean perioperative HBL was 614.72 ± 368.14 mL, which accounted for 84.05% of the mean total perioperative blood loss (731.37 ± 391.50 mL). The mean preoperative HBL was 368.33 ± 325.57 mL, which accounted for 50.36% of the mean total perioperative blood loss. Patients with fracture types AO/OTA 31-A2.2 to A3.3 had more severe preoperative HBL (median 580.10 mL), and most of them developed mild-to-moderate anemia before the operation, and 27.63% of them received preoperative blood transfusion. Compared with patients operated within 5 days after injury, patients operated over 5 days had lower Hb value at admission (101.56 ± 19.49 vs. 107.28 ± 16.53; P = 0.026) and higher preoperative transfusion rate (25.84% vs. 9.01%; P = 0.001). Multiple linear regression analysis revealed that fracture types AO/OTA 31-A2.2 to A3.3, male sex, right-sided injury, and operation time > 60 min were independently associated with increased perioperative HBL. Tranexamic acid treatment was negatively correlated with perioperative HBL.<bold>Conclusion: </bold>IFs in elderly patients undergoing intramedullary fixation surgery were associated with significant perioperative HBL and anemia. Persistent HBL occurred before the operation and on the first few postoperative days. Surgeons should pay more attention to preoperative HBL in patients with fracture types AO/OTA 31-A2.2 to A3.3 and regularly measure Hb levels preoperatively to avoid anemia. Shortening preoperative time may helps to reduce preoperative blood loss. [ABSTRACT FROM AUTHOR]