To the Editor:—
Matot et al. reported a significant reduction in exposure to allogeneic blood transfusion by acute normovolemic hemodilution (ANH) in adult patients undergoing elective liver resection. 1They also concluded that ANH could be routinely considered for this surgical procedure. 1As discussed in this article and reviewed elsewhere, it is possible that biased experimental designs were, in part, responsible for the previously reported efficacy of ANH. 2ANH has also been argued to profit to a restricted subgroup of patients difficult to identify. 2In this respect, we believe that Matot et al. conclusions warrant some comments. Indeed, it has long been accepted that there is a considerable risk of massive bleeding during elective liver resection. 3However, improvements in surgical techniques, technology, and preoperative assessment, in conjunction with a better understanding of the functional anatomy of the liver, have dramatically reduced the risk of bleeding during elective liver resection. 4,5,6Moreover, situations likely to cause intraoperative bleeding can be anticipated, 4such as preexisting adhesions resulting from previous surgery, organ removal, cava or portal vein resection, or recanalization. 4The tolerance of lower intraoperative hemoglobin concentrations, together with the limitation of intraoperative fluid administration, has contributed to the decrease in intraoperative transfusion requirement in elective liver resection. 1,4,7Indeed, a 30% transfusion rate has been reported in series of nonselected patients undergoing elective liver resection. 4Selected patients, including ASA 1, Child A cirrhotic patients, underwent major liver resection without blood transfusion. 5Consequently, the 40% transfusion rate recorded by Matot et al. in the control group is higher than is currently routinely expected in specialized centers, thus suggesting that a selected population carrying an increased bleeding risk was operated on in this institution.
In conclusion, we believe that the findings of Matot et al. recorded in patients undergoing elective liver resection still substantiate previous concerns regarding ANH. 2ANH is strongly suggested to reduce transfusion requirement in elective liver resection. Nevertheless, the subgroup of patients likely to have a benefit from ANH remains a poser.