Anales de la RANM

71 A N A L E S R A N M R E V I S T A F U N D A D A E N 1 8 7 9 POSTOPERATIVE BLOOD SALVAGE AFTER KNEE ARTHROPLASTY Valbuena I, et al. An RANM. 2022;139(01): 67 - 77 Dispite the existence of a Protocol for Preoperative Optimisation of Anaemia, this was not applied in all cases, resulting in 23.9% of patients who presented preoperative anaemia with hemoglobin levels (Hb) < 13 g/dL at the time of surgery. Only 2.4% had an Hb level < 11 g/dl being the lower Hb level 9.5 g/dl. Preoperative anaemia was significantly more prevalent in ASA (American Society of Anesthesio- logists Classification) II and III patients (p=0,02). ABT prescription was guided by a Restrictive Transfusion Protocol (no patient receive packed red blood cells transfusion for Hb greater than 8 g/dL, or 10 mg/dL in cardiovascular risk patients, and that all of them were administered in one unit increments followed by re-evaluation of blood parameters). Patients who received ABT accounted for 26.5% of total cases, mainly in the late postope- rative period (> 24 hours). 69.6% received 2 units of red blood cells and 11.6% received more than 2 units, equivalent to an average volume of 518.12+232.153 mL. In the group without BS, 33.1% (43) patients received blood transfusion, versus 20% (26) in the group with BS exposed (OR: 95%CI 1.65 (CI 1.085-2.52); p=0.024). PACU time was 19.8 + 15.8 hours and the length of hospital stay (LOS) was 9.8 + 3.9 days (figure 2). Patients in the BS exposed group had higher mean hemoglobin (Hb) (p= 0.029) and hematocrit (HTC) (p=0.009) at 24 and 48 hours than the non-BS group (figure 3). Furthermore, with a stratified analysis, patients treated with anti-platelet therapy (APT) without BS exposure received more ABT (58.3%) versus those without APT (25%), p=0.039. The use of BS had no influence on PACU time and overall hospita- lization time. M ale gender, atrial fibrillation, preope- rative anti-platelet therapy and cementless primary TKA were identified as risk factors for postoperative bleeding (table 3). As expected, atrial fibrillation was associated with a significant increase in oral anticoa- gulation in 58.3% of patients and low weight molecular heparin (LWMH) therapy in 41.7% (p<0.001). The ASA classification status > II (figure 4), preope- rative Hb values < 13 g/dl, knee revision, APT, longer surgery time and total time were identified as risk factors for ABT (table 3). Moreover, a higher preope- rative Hb level was associated with a lower risk of transfusion (RR=1.959 [1.455-2.639]). Anesthesia or postoperative analgesia technics did not influence the rate of ABT. Patients receiving ABT presented lower hemoglobin and hematocrit values (p<0.001), and a longer PACU time (+7 hours in PACU, p<0.001) and medium LOS (+2.5 days in LOS p=0.026). Figure 1. Consort diagram.