Approximately one million bags of blood are delivered annually to Canadian hospitals. About half of these are administered to surgical patients. We have examined patterns of blood utilization among patients undergoing liver operations. We have identified that about one third of all blood administered in this group was unnecessary. We have then focused on transfusions given in the operating room as a target for improvement, as this environment remains an unexplored “black box”. We have examined evidence from clinical trials, as well as practice guidelines to better understand the lay of the land. We have identified that clinicians rely heavily on rapid hemoglobin blood tests to make decisions about transfusion during surgery and have found that the literature does not support their use. More recently, we have obtained funding to carry out a large-scale examination of these devices in a real-world environment, to define their role in decision-making.

Blood transfusions in liver surgery remain common. Transfusions can be lifesaving, but inappropriate transfusions lead to no clinical benefit and potentially to harm. Patient blood management programs in surgery aim to minimize clinically indicated transfusions, and to eliminate inappropriate transfusions. This research program aimed to tackle these issues in liver surgery, and in all surgical disciplines more broadly.
We first defined the epidemiology of perioperative transfusion in liver surgery. A cohort liver operations (2011-2018) was audited. Published instruments were used to adjudicate transfusion appropriateness. A total of 489 patients underwent liver resection (transfusion incidence 18.6%, 241 units given). A total of 23-49% of intraoperative transfusions and 38-48% of postoperative transfusions were considered inappropriate.
Transfusion decision-making in the operating room was identified as a major knowledge gap. We thus conducted a systematic review of intraoperative transfusion guidelines. Ten guidelines were identified. They were noted to be highly variable in their recommendations and to lack a sufficient evidence base from the intraoperative setting. A second systematic review was conducted to identify clinical trials that tested intraoperative transfusion strategies. Fourteen trials were found, in which intraoperative restrictive transfusion strategies decreased perioperative transfusions without added postoperative morbidity and mortality in 12/14 trials. Two trials reported worse outcomes. Given trial design and generalizability limitations, uncertainty remains regarding the safety of broad application of restrictive transfusion triggers in the operating room.
We have identified hemoglobin measurement in the operating room as a major determinant of transfusion decision-making. Hemoglobin is most measured using convenient point-of-care testing devices. We have conducted a meta-analysis of 32 studies and concluded that such devices provide results that are frequently outside of the reference standard. We have then secured funding for a large prospective observational study to examine point-of-care testing devices for patients at high risk of transfusion. This work was recently completed and involved the prospective accrual of 1735 blood samples in surgery. Results are currently under analysis.
In summary, we have examined the epidemiology of blood transfusion in liver surgery. This work has identified intraoperative blood transfusions as a significant knowledge gap and area for improvement in surgery more broadly.

https://doi.org/10.1097/sla.0000000000004710
https://doi.org/10.1136/bmjopen-2019-029684
https://doi.org/10.1097/sla.0000000000004931
https://doi.org/10.1093/bjs/znac389
https://doi.org/10.1007/s12630-020-01857-4
https://doi.org/10.1111/trf.17242
https://doi.org/10.1002/bjs.11463
https://doi.org/10.1186/s13063-022-07008-y
And 5 more papers currently under review at various journals