SA1 - Acute Normovolemic Hemodilution in Head and Neck Reconstructive Surgery

Abstract: Acute normovolemic hemodilution (ANH) is a well-established blood conservation strategy most discussed in cardiothoracic and orthopedic surgery literature. Simply, the technique involves drawing a predetermined volume of blood from a patient at the beginning of surgery and transfusing the same autologous blood to the patient when most of the anticipated blood loss is complete. The immediate goal of ANH is to reduce the need for allogeneic blood transfusions in patients undergoing surgery with high anticipated blood loss. Additionally, the use of less allogeneic blood products reduces rates of allograft transfusion reactions and saves critical hospital resources [1]. Cancer patients who receive allogeneic blood during surgery and hospitalization have been shown to have reduced recurrence and all-cause mortality [2].

Our study is a single-center, retrospective study of 110 consecutive patients at High Desert Oral and Facial Surgery and University Medical Center of El Paso. The first 55 patients (control group) underwent free tissue transfer for head and neck reconstruction without ANH. The following 55 patients (study group) underwent free tissue transfer for head and neck reconstruction with ANH. Patients were excluded if they had preoperative anemia, history of kidney failure requiring hemodilution, history of liver failure, or American Society of Anesthesiologist (ASA) Class IV or greater. The ANH protocol involved a 500cc blood draw after induction and prior to the start of the operative portion of the case. This blood was administered after the completion of the ablative portion and flap harvest when most anticipated blood loss was complete. Transfusion criteria were hemoglobin less than 7 g/dL or hemodynamic instability requiring the sustained use of vasopressors. Data was collected on age, total blood loss, hemoglobin and hematocrit both pre- and post-operatively, and use of allogeneic blood transfusion.

The study group received less allogenic blood both intraoperatively (p < 0.05) and in the postoperative period (p < 0.05). There was no statistical difference between the groups in the average age, percentage of each sex, intraoperative blood loss, percentage of patients undergoing reconstruction for oncologic versus benign disease. Major and minor flap complications were lower in the ANH group but not statistically different.

Acute normovolemic hemodilution is an established strategy for blood conservation in other surgical disciplines. It is effective in reducing allogeneic blood transfusion in head and neck reconstructive patients.

References
1. Monk T. G. (2005). Acute normovolemic hemodilution. Anesthesiology clinics of North America, 23(2), 271–vi. https://doi.org/10.1016/j.atc.2005.03.002

2. Petrelli, F., Ghidini, M., Ghidini, A., Sgroi, G., Vavassori, I., Petrò, D., Cabiddu, M., Aiolfi, A., Bonitta, G., Zaniboni, A., & Rausa, E. (2021). Red blood cell transfusions and the survival in patients with cancer undergoing curative surgery: a systematic review and meta-analysis. Surgery today, 51(10), 1535–1557. https://doi.org/10.1007/s00595-020-02192-3