Outliers
Current National Institute for Health and Care Excellence (NICE) guidelines recommend using a restrictive RBC transfusion threshold of 70g/litre (80g/litre if concomitant cardiovascular disease) and a Hb concentration target of 70-90g/litre after transfusion. Furthermore, single-unit transfusions for adults who are not actively bleeding have been shown to be more clinically beneficial and cost-effective when compared to liberal RBC transfusion targets.20 A subgroup analysis revealed a total of 57 instances out of 187 transfusion orders that were requested above the threshold advised by NICE. Of these, 20 were outliers after excluding those that were actively bleeding or symptomatic with borderline Hb levels. These can be divided into 14 outliers who were transfused due to flap formation, 5 that were transfused due to senior clinician request and 1 case having units ordered but not given.
Ensuring HNC patients only receive allogeneic blood transfusions if necessary is important, as there is growing evidence that their use is associated with worse patient outcomes. Szakmany et al. found a statistically significant increase in mortality for patients undergoing primary surgery for oral and oropharyngeal cancer with free flaps when they received three units or greater.21 Danan et al. replicated these results in a retrospective study in patients undergoing free flap reconstruction for head and neck cancer, showing not only a reduction in overall survival but also an increase in wound infection.22 It has also been shown that liberal transfusion practice does not improve tissue oxygenation for free flap reconstruction.23 The individualised practices of surgeons adds colour to the results in this patient group.
HNC surgeons propose several reasons for post-operative transfusion. These include: improving the Hb concentration to optimise tissue healing, in preparation for adjuvant oncological treatment and avoid potential cardiac complications in high-risk patients. This practice is idiosyncratic and assertions to such outcomes are yet to be substantiated by robust research and appear anecdotal.24