(P 512) PERIOPERATIVE BLOOD MANAGEMENT IN PEDIATRIC PATIENTS UNDERGOING PRIMARY OSTEOSARCOMA AND EWING SARCOMA RESECTION: A RETROSPECTIVE CASE NOTE REVIEW

Objective: Resection of osteosarcoma and Ewing sarcoma constitutes major surgery and can be associated with significant blood loss [1,2]. Along with the high incidence of preoperative anemia in cancer patients due to neoadjuvant therapy, this means allogeneic red blood cell (RBC) transfusion is often needed perioperatively. Blood transfusion can cause significant changes in the immune response of the recipient (transfusion related immunomodulation) [3], which is associated with infection and may increase recurrence in some cancers [4,5]. Intraoperative blood conservation strategies, such as cell salvage, may improve the quality of care for patients undergoing sarcoma resection by reducing or eliminating the need for allogeneic RBC transfusion.

We aimed to evaluate perioperative blood management and transfusion practice in children undergoing sarcoma resection in our tertiary pediatric centre and identify opportunities for quality improvement (QI).

Methods: We conducted a retrospective review of all primary osteosarcoma and Ewing sarcoma resection surgeries that occurred in children aged 0-18 years between January 2005 and September 2021 at British Columbia Children’s Hospital, Vancouver, Canada. There were no exclusion criteria. As a QI study, our institutional research ethics board waived the requirement for ethical review. Data collection via manual case note review focused on patient demographics, tumour and procedure details, volume and timing of transfusion, perioperative hemaglobin (Hb), and any complications related to transfusion during the perioperative period (up to 72 hours post-surgery). Anemia was defined as Hb < 120 g/L.

Primary outcomes included the proportion of patients who received an allogeneic RBC transfusion and the volume of RBCs administered (mL/kg). Secondary outcomes included proportion of patients with preoperative anemia, pre- and postoperative Hb level, and complication rates associated with RBC transfusion. Generalized linear models were used to evaluate factors associated with increased perioperative allogeneic RBC transfusion.

Results: A total of 72 patients of median [interquartile range (IQR)] age 14 [11; 15] were included. Demographic data were similar between patients that received an RBC transfusion vs. those that did not (Table 1).

Preoperatively, 59/70 (84%) patients were anemic, with a median [IQR] Hb of 108 g/L [99; 117]; all patients (59/59) were anemic postoperatively, with a day one median Hb of 90 g/L [80; 102].

An RBC transfusion was given to 45/72 (63%) patients intraoperatively, with a median [IQR] volume of 608 mL [424; 1096], and to 28/72 (39%) patients postoperatively, with a volume of 558 mL [303; 892] (Table 2).

An RBC transfusion was given in all seven cases with a pelvic tumour. Tumour in the pelvis was associated with an increased volume of RBC transfusion intraoperatively with a mean difference [MD] of 30.9 mL/kg (95%CI 20.7 to 41.2). Other factors associated with an increased volume of RBC transfusion perioperatively included presence of metastatic disease at time of surgery (MD 3.4 mL/kg, 95%CI 0.5 to 6.3) and tumour in the upper leg (MD 3.1 mL/kg, 95%CI 0 to 6.2) (Table 3).

In patients that received an RBC transfusion postoperatively, 3/26 (12%) experienced a transfusion-related complication: two experienced fever up to 39°C and one developed fever and subjective chills.

Conclusion: This retrospective review suggests that perioperative anemia is common in patients undergoing primary resection of osteosarcoma or Ewing sarcoma. Perioperative allogeneic RBC transfusion is often required, especially in patients with existing metastatic disease or with a pelvic tumour. This was associated with transfusion related complications. Avoiding allogeneic RBC transfusion may be beneficial in some cases. Further research into potential benefits and safety of blood conservation strategies, such as intraoperative cell salvage, may be warranted in this patient population.