Data extraction
Each patient had their electronic patient records reviewed and the following parameters analysed: Indication for RBC transfusion; number of units transfused; type of operation (if performed) in preceding 30 days; elective or emergency admission; haemoglobin (Hb) before transfusion. A regression analysis was conducted for continuous variables between RBC use in HNC surgery with reconstruction and RBC use in HNC surgery without reconstruction. Statistical analyses were performed using IBM Statistical Package for the Social Sciences (SPSS) 25 software by SPSS Inc. Furthermore, A cost-analysis of RBC units was performed for each year based on the NICE costing statement.11