**2.5 Patient blood management and preoperative blood conservation strategies**

Anemia is frequent among patients undergoing hip replacement, and its prevalence has been estimated to be up to 25% in patients undergoing hip surgery and markedly increased in the postoperative [25, 26]. The main causes of preoperative anemia are summarized in **Table 3**. Preoperative anemic patients are more likely to receive allogeneic blood transfusions than nonanemic patients. It has been suggested that preoperative anemia and increased blood transfusion rates were independently associated with an increased risk of perioperative adverse outcomes, such as increased postoperative infections, increased hospital length of stay, and increased mortality [27]. Large variability in clinical practice in patient blood management in major orthopedic surgery has been described despite orthopedic surgery is one of the field with the greatest tradition in these programs [26]. Moreover, among patients with anemia, the currently available evidence does not support the use of liberal red blood cell transfusion thresholds based on a 10 g/dL hemoglobin trigger in preference to more restrictive transfusion thresholds based on lower hemoglobin levels or symptoms of anemia in patients undergoing hip fracture surgery [28]. However, criticism on the randomized clinical studies on blood transfusion threshold has been raised regarding the study design and the fact that the decision to transfuse should not be based only on hemoglobin concentrations [29]. Moreover, recent studies using


#### **Table 3.**

*Main cause of anemia in patients undergoing hip surgery.*

sublingual microcirculation monitoring have shown that in critically ill patients with microcirculatory impairment, blood transfusion is able to improve the microcirculation regardless of hemoglobin levels [30, 31]. On the contrary, among patients with normal microcirculation, there are no changes regardless of hemoglobin concentration [30, 31]. Finally, the treatment of preoperative anemia with iron, with or without erythropoietin, and perioperative cell salvage has been reported to decrease the need for blood transfusion [27].

A patient blood management protocol should be adopted in each center and updated regularly. Where feasible, patients programmed for elective surgery should receive a blood count no more than 30 days before surgery, and anemic patients should be referred to the specialist to investigate and treat anemia. The reports of the blood chemistry tests and martial balance are the most common tests for the evaluation of preoperative anemia. The dosage of ferritin, transferrin saturation, and sideremia allow, together with the complete blood count, to make a differential diagnosis of anemia and to personalize the preoperative therapy. **Figure 1** shows a proposed protocol for patient blood management in the preoperative phase.

For the treatment of anemia, there are both intravenous (IV) and oral preparations. Iron sulfate, iron gluconate, and ferric carboxymaltose are the most common in use. Ferric carboxymaltose is usually preferred since it penetrates the bone marrow faster than the other preparation and more rapidly raises the level of serum hemoglobin. This preparation is for intravenous administration only (**Table 4**).

The erythropoiesis stimulating agents (erythropoietin) represents another therapeutic strategy in the patient blood management. The most important indication for the use of erythropoietin perioperatively is the optimization of autologous donation, when indicated or to reduce exposure to allogeneic blood transfusions in adult patients undergoing major elective orthopedic surgery who are at high risk of massive transfusion or for whom a predeposit autologous donation is not available and a blood loss of more than 1000 mL is expected. There are two possible schemes for the use of erythropoietin:


#### **Figure 1.**

*One of the possible protocols to adopt in the preoperative evaluation of patients undergoing hip surgery inside a patient blood management program.*


#### **Table 4.**

*The cumulative dose of ferric carboxymaltose to be administered on the basis of body weight and hemoglobin levels.*
