Estimating Blood Loss In Abdominal-based Breast Reconstruction: How Accurate Are We?
David W. Nash, MD, Nicolas Greige, BS, Katie Weichman, MD.
Montefiore/Einstein, New York, NY, USA.
PURPOSE: The relationship between estimated blood loss (EBL) and actual blood loss (ABL) has yet to be elucidated in abdominal-based autologous breast reconstruction. Our objective was to evaluate the effect of reconstruction timing and laterality on the accuracy of EBL.
METHODS: We reviewed all patients that underwent abdominal-based free flaps for breast reconstruction at our institution from 2009-2019. ABL was calculated using the formula ABL=(EBVxHcti-Hctf)/Hcti, where EBV denotes estimated blood volume (weight in kg x 65 mL/kg), and Hcti and Hctf denote preoperative and immediate postoperative hematocrit, respectively. Percent difference between ABL and EBL (PDAE) was calculated as (ABL-EBL)/ABL.
RESULTS: 286 patients were analyzed. EBL in unilateral operations was significantly less than bilateral operations (250 vs. 330mL, p<0.001), however there was no significant difference in the PDAE (71.5 vs. 68.8%, p=0.056). EBL was significantly greater (305 vs. 200 mL, p<0.001) and PDAE was significantly less (68.4 vs. 72.2%, p=0.02) in immediate compared to delayed operations. Patients requiring transfusion had significantly increased EBL (338 vs. 274mL, p<0.01) and required significantly more intraoperative fluids (57.7 vs. 46.6mL/kg, p<0.001). Logistic regression analysis, with postoperative transfusion as the outcome, demonstrated that operative time (OR=1.19, p=0.02) and intraoperative fluids (OR=1.03, p=0.01), but not EBL (OR=1.00, p=0.11), were significantly associated with transfusion events.
CONCLUSION: In abdominal-based breast reconstruction blood loss is underestimated by 57-79%. Error in EBL was greatest in delayed reconstructions. Operative time and intraoperative fluids requirements, but not EBL, significantly predicted need for transfusion in our regression model.
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