Impact of intraoperative hypovolemic phlebotomy on blood loss and perioperative transfusion in patients undergoing hepatectomy for cancer

Abstract

Background: Intraoperative blood loss (IOBL) and allogeneic blood transfusion are important determinants of outcome in patients undergoing elective hepatectomy for cancer. We assessed whether intraoperative hypovolemic phlebotomy (HP) used to perform hepatectomy under low central venous pressure (CVP) was associated with lower IOBL and perioperative transfusion rates, and whether these factors were linked to patient oncological outcomes. Methods: Restrospective analysis of a prospectively maintained database of consenting patients who underwent hepatectomy for primary and secondary liver malignancies between 01/2011 and 06/2017 in one academic center. Perioperative blood transfusion was defined as red blood cell unit transfused during hepatectomy until hospital discharge, and data were extracted from the hospital transfusion medicine database. We used the Fisher’s exact test to compare proportions, the Mann-Whitney or the Kruskal-Wallis tests to compare means, the Spearman r test for correlations, and Log Rank test and Cox regression for associations of variables with survival outcomes. Results: Intraoperative HP was used in 520 (76.0%) of the 684 patients included in this study. The median phlebotomy volume was 400 ml (range 50 to 900 ml), and median volume per patient weight was 5.3 ml/kg (range 0.5 to 30.1 ml/kg). Patients with large HP (>5.3 ml/kg) had lower IOBL than those with smaller HP (507 ml vs. 640.2 ml, p = 0.008). HP volume/weight was negatively correlated with IOBL (Spearman r = -0.11, p = 0.019). The perioperative transfusion rate was 14.6% in patients when HP was used, compared to 22.2% (p = 0.022) when HP was not used. The transfusion rate was lower in HP patients compared to non-HP patients even though more major hepatectomies (≥4 segments) (36.0% vs. 27.1%, p = 0.02) and less laparoscopic surgery (4.9% vs. 11.1%) were done in the HP group. Intraoperative HP reduced the perioperative transfusion risk by 8.9% (relative risk 0.91, 95% CI 0.82 to 0.99), and the number needed to treat to avoid one transfusion was 13 patients. The preoperative three-point transfusion risk score (hemoglobin 12.5 g/dl or less, primary liver malignancy, and resection of ≥ 4 liver segments) stratified patients by low vs. high transfusion requirements (13.3% if score 0 or 1 vs. 31% if score 2 or 3, p < 0.0001), irrespective of the use of HP. We did not find a significant association between IOBL or perioperative transfusions and recurrence-free or disease-specific survival. Conclusion: Intraoperative HP in patients undergoing hepatectomy was associated with lower IOBL and a perioperative transfusion rate of 14.6%, which was lower than non-HP patients and the 22% to 32% rate reported in contemporaneous series. Prospective studies with optimized preoperative hemoglobin level, standardized intraoperative hemostatic and fluid management methods, and defined perioperative transfusion criteria are needed to determine whether HP is superior to other anesthesiological techniques of low CVP for reducing IOBL and transfusion requirements.