The Effect of Preoperative Anemia on Blood Transfusion Outcomes in Major Head and Neck Cancer Surgery.

: Major head and neck oncologic surgeries requiring microvascular reconstruction frequently result in complications such as perioperative blood transfusion (PBT). Not only are blood products overutilized and associated with risks, but preoperative anemia is both a modifiable and predisposing factor for PBT. Our objective was to assess risk factors for PBT and determine a high-risk preoperative hemoglobin to inform transfusion stewardship practices. : Patients that underwent head and neck cancer free flap reconstruction ( = 363) between 2012 and 2019 were included. Univariable and multivariable analyses evaluated predictors of PBT. : Overall, 11% of patients were anemic and 19% were transfused. Mean preoperative hemoglobin was significantly lower in the PBT group (128 g/L vs. 145 g/L, < 0.0001). In our multivariable model, lower preoperative hemoglobin (odds ratio [OR] = 0.94), higher T stage (OR = 2.65), and lower body mass index (BMI) (OR = 0.89) increased the odds of PBT. Adjusting for staging and BMI, the OR of PBT was increased below 120 g/L hemoglobin. Higher mean units of PBT were administered for hemoglobin below 150 g/L with a large inflection below 120 g/L ( < 0.0001). : Low preoperative hemoglobin is the strongest predictor of PBT in major head and neck cancer surgery. Recognizing and managing anemia is essential in surgical planning.