Delay in detection and treatment of perioperative anemia in hip fracture surgery and its impact on postoperative outcomes

•Question: For how long are patients with hip fracture anemic in the perioperative period, and what is the impact of time spent in the anemic state on outcomes?•Findings: Patients may spend hours with undetected/uncorrected anemia in the perioperative period; time spent in the anemic state was associated with delirium.•Meaning: Continuous monitoring could potentially lead to earlier discovery and correction of anemia and improve outcomes. Elderly patients with hip fractures are at high risk for perioperative anemia as a result of fracture- and surgery-related blood loss. The detection of anemia is dependent on intermittent blood samples and therefore might be delayed, potentially leading to a significant delay in transfusion. This study aimed to investigate the possible delay in perioperative anemia detection, accumulated perioperative anemia-associated burden, peripheral perfusion, and their association with patient outcomes in elderly patients with hip fracture. Elderly patients with acute hip fracture scheduled for surgery were enrolled in this prospective study from August 2016 to December 2016. All patients were monitored continuously for hemoglobin concentration (SpHb) and perfusion index (PI) with the Radical-7® Pulse CO-Oximeter® and Rainbow® R1 Adhesive Multi-parameter Sensors (Masimo Corp., Irvine, CA, US) from 12 h presurgery to 24 h postsurgery. Fifty-one patients were enrolled, and 41 were included in the final analyses. Mean delay in the detection of low Hb (