Intraoperative Blood Management Strategies for Patients Undergoing Noncardiac Surgery: The Ottawa Intraoperative Transfusion Consensus.

IMPORTANCE: There is marked variability in red blood cell (RBC) transfusion during the intraoperative period. The development and implementation of existing clinical practice guidelines have been ineffective in reducing this variability. OBJECTIVE: To develop an internationally endorsed consensus statement about intraoperative transfusion in major noncardiac surgery. EVIDENCE REVIEW: A Delphi consensus survey technique with an anonymous 3-round iterative rating and feedback process was used. An expert panel of surgeons, anesthesiologists, and transfusion medicine specialists was recruited internationally. Statements were informed by extensive preparatory work, including a systematic reviews of intraoperative RBC guidelines and clinical trials, an interview study with patients to explore their perspectives about intraoperative transfusion, and interviews with physicians to understand the various behaviors that influence intraoperative transfusion decision-making. Thirty-eight statements were developed addressing (1) decision-making (interprofessional communication, clinical factors, procedural considerations, and audits), (2) restrictive transfusion strategies, (3) patient-centred considerations, and (4) research considerations (equipoise, outcomes, and protocol suspension). Panelists were asked to score statements on a 7-point Likert scale. Consensus was established with at least 75% agreement. FINDINGS: The 34-member expert panel (14 of 33 women [42%]) included 16 anesthesiologists, 11 surgeons, and 7 transfusion specialists; panelists had a median of 16 years' experience (range, 2-50 years), mainly in Canada (52% [17 of 33]), the US (27% [9 of 33]), and Europe (15% [5 of 33]). The panel recommended routine preoperative and intraoperative discussion between surgeons and anesthesiologists about intraoperative RBC transfusion as well as postoperative review of intraoperative transfusion events. Point-of-care hemoglobin testing devices were recommended for transfusion guidance, alongside an algorithmic transfusion protocol with a restrictive hemoglobin trigger; however, more research is needed to evaluate the use of restrictive triggers in the operating room. Expert consensus recommended a detailed preoperative consent discussion with patients of the risks and benefits of both anemia and RBC transfusion and routine disclosure of intraoperative transfusion. Postoperative morbidity and mortality were recommended as the most relevant outcomes associated with intraoperative RBC transfusion, and transfusion triggers of 70 and 90 g/L were considered acceptable hemoglobin triggers to evaluate restrictive and liberal transfusion strategies, respectively, in clinical trials. CONCLUSIONS AND RELEVANCE: This consensus statement offers internationally endorsed expert guidance across several key domains on intraoperative RBC transfusion practice for noncardiac surgical procedures for which patients are at medium or high risk of bleeding. Future work should emphasize knowledge translation strategies to integrate these recommendations into routine clinical practice and transfusion research activities.