OA2-AM24-MN-39 - Complication Rates in Patients with Sickle Cell Disease on Hydroxyurea Managed With or Without Pre-Anesthesia Transfusion

Patients with sickle cell disease (SCD) are at increased risk of complications including acute chest syndrome (ACS) and vaso-occlusive pain episodes (VOE) following general anesthesia (GA). The American Society of Hematology suggests preoperative transfusion for patients with SCD requiring GA lasting >1 hour though risk of surgery, baseline hemoglobin (Hb), and disease severity should also be considered. With the increased use of Hydroxyurea (HU) to raise Hb levels in patients with HbSS and HbSB⁰ thalassemia, we lack equipoise for when pre-GA transfusion is indicated. We investigated clinician practice of transfusing red blood cells (RBCs) pre-GA versus not, and post-GA complication rates in patients with SCD on HU at our institution.

Study

Design/Methods:

We performed a single institution IRB-approved retrospective chart review of 122 patients with HbSS and HbSB⁰ thalassemia aged 0 to 22 years who underwent procedures with GA between 2019 and 2023. We categorized patients into 3 groups (72 on HU, 42 on chronic transfusion therapy and 8 on neither). Surgical risk score was assigned for 130 procedures among the 122 patients per the Transfusion Alternatives Preoperatively in SCD (TAPS) study criteria (4 high, 62 medium, 64 low risk). For the HU group, we determined if patients were transfused pre-GA, and recorded complications (e.g. VOE, ACS) occurring within 30 days post-GA.

Results/Findings: Among 72 patients with HbSS or HbSB⁰ thalassemia on HU, who had 76 GA encounters, the mean baseline Hb was 8.6 g/dl. Fifty-one encounters were managed with pre-GA transfusion (67%, 49 simple, 2 red cell exchange (RCE)). The mean pre-transfusion Hb was 8.3 g/dl (range 4.8 - 11.2 g/dl) for patients who received a simple transfusion and 9 g/dl (range 8.3 - 9.7 g/dl) for RCE. Among 51 GA encounters managed with transfusion, complications occurred in 5 (9.8%): 2 ACS, 2 VOE and 1 with both ACS and VOE in 1 high, 3 medium, and 1 low risk procedures. Among 25 GA encounters without transfusion, the mean Hb was 9.1 g/dl (range 7.7 g/dl - 12.2 g/dl), n = 11 < 9 g/dl). Complications occurred in 4 (16%), one of whom had a Hb < 9 g/dl: 3 ACS and 1 with both ACS and VOE in 2 medium and 2 low risk procedures. For comparison, 4 of 46 encounters (8.7%) among patients on chronic transfusion were associated with complications during the study period (4 VOE: 2 medium, 2 low risk procedures).

Conclusions: Clinician practice varies for pre-GA transfusion management of patients with HbSS or HbSB⁰ thalassemia on HU. Transfusion was not prescribed in 44% of encounters in patients on HU with a Hb < 9 g/dl. The complication rate trended higher for patients on HU who did not receive pre-GA transfusion compared to those who were transfused. While HU may increase baseline Hb and decrease VOE/ACS frequency, patients with SCD may continue to benefit from pre-GA transfusion but a prospective, multi-institutional study is needed.