A novel approach to preoperative blood orders.

1250 June 2013 W ORLD-WIDE, several hundred million operations are performed each year. A substantial fraction require blood transfusion, often with little forewarning. Because crossmatching and antibody screening takes time, it is conventional to either typeand-screen or crossmatch blood for patients likely to require transfusion. The clinical challenge is to predict who will require transfusion—and how many units. This is where the Maximum Surgical Blood Order Schedule can be helpful. Frank et al.,1 in this issue of the Journal, present a novel and largely objective method for determining operationand institution-specific maximum blood order guidelines; that is, recommendations for type-and-screen or the crossmatching of units for particular procedure classes. The authors used their institution’s electronic anesthesia records and blood bank database to compare type-and-screen and crossmatch orders with intraoperative transfusions. (Postoperative transfusions are of less concern because they are rarely emergent; crossmatching can thus, be done at the time blood is ordered.) The results, unsurprisingly, showed that far more patients get type-and-screens or units crossmatched than actually get transfused. The investigators used their data to develop a statistical algorithm for generating operationspecific maximum blood order guidelines. Friedman et al.2 created a Maximum Surgical Blood Order Schedule in 1976, which recommended how many units of blood should be crossmatched or type-and-screened preoperatively for common elective surgical operations. The goal of creating a maximum surgical blood order schedule is to reduce unnecessary laboratory work and to reduce the time that a unit is reserved (i.e., crossmatched) for a single patient. The creation of the maximum surgical blood order schedule at most facilities is primarily based on consensus.3,4 In other words, the blood bank director solicits a group of surgeons for their thoughts as to the expected blood loss for a particular procedure. How this solicitation takes place is institution-specific, as is how often the maximum surgical blood order schedule is revised. Although consensus-based guidelines are an improvement over individual judgment, they lack the rigor of quantitative recommendations based on objective institutional data. The authors evaluated intraoperative erythrocyte transfusion needs in 1,632 adult procedures that were grouped into 135 internally similar categories, based on surgical specialty and anatomic location. Patients undergoing ophthalmologic surgery were excluded. The general approach was to assign each surgical category to one of five recommendations for pretransfusion testing based on the fraction of patients requiring transfusion, median blood loss, transfusion index (ratio of transfused units to patients), a priori risk of major bleeding (as determined by consensus with surgeons), and whether the operation was major vascular or transplant. The algorithm is novel in being largely objective. In this regard, it differs from previous maximum blood order proposals which were primarily consensus based.5,6 A difficulty in comparing maximum blood orders among hospitals is that institutions differ not only in the types of operations they perform, but also in the skill and technique of the surgeons who perform them, the variation in application of blood conservation strategies, and tolerance for anemia. Consequently, maximum blood order guidelines for one institution may generalize poorly to others. Similarly, national guidelines—even if objective—would strive to represent typical rather than specific institutions. A second novel aspect of the algorithm proposed by the authors is that it can be applied to the transfusion data from other institutions. (The specific methods are presented in A Novel Approach to Preoperative Blood Orders