Expanding restrictive transfusion evidence in surgical practice: a multicentre, prospective cohort study

Predeposit Autologous Blood Donation in Rh(D)-Negative Pregnant Women: A Single-Center Study

Objective  The primary purpose of this study was to assess the practicability of predeposit autologous blood donation (PABD) in the practice of Rh(D)-negative pregnant women. Materials and Methods  A cohort of 405 Rh(D)-negative pregnant women who had a delivery in the comprehensive tertiary hospital in Nanjing was analyzed retrospectively, over 10 years. Results  After PABD, 203 women experienced a slight drop in mean hemoglobin of 5.32 ± 0.5 g/L (PABD-associated anemia was not featured in our study). Thirteen women who received allogeneic blood might benefit from PABD practically. Conclusion  PABD is applicable for Rh(D)-negative pregnant women, as it ensures the availability of the patient's blood in the event of perinatal hemorrhage, thus minimizing the need for transfusion from external sources. Despite the autologous blood reinfusion of low proportion, PABD could still serve as an alternative when allogeneic blood resources are scarce. However, one challenge in the future is to identify candidates who may benefit most from PABD. Also, more attention is needed to raise awareness of patient blood management. Recommended strategies include early screening and treatment of anemia, hemostasis promotion, and blood loss reduction. Replacement of allogeneic transfusion with autotransfusion could be referred to where feasible. We believe that PABD still has a promising potential for application in Rh(D)-negative pregnant women.

Generating real-world evidence compatible with evidence from randomized controlled trials: a novel observational study design applicable to surgical transfusion research

BACKGROUND

Numerous observational studies have revealed an increased risk of death and complications with transfusion, but this observation has not been confirmed in randomized controlled trials (RCTs). The "transfusion kills patients" paradox persists in real-world observational studies despite application of analytic methods such as propensity-score matching. We propose a new design to address this long-term existing issue, which if left unresolved, will be deleterious to the healthy generation of evidence that supports optimized transfusion practice.

METHODS

In the new design, we stress three aspects for reconciling observational studies and RCTs on transfusion safety: (1) re-definition of the study population according to a stable hemoglobin range (gray zone of transfusion decision; 7.5-9.5 g/dL in this study); (2) selection of comparison groups according to a trigger value (last hemoglobin measurement before transfusion; nadir during hospital stay for control); (3) dealing with patient heterogeneity according to standardized mean difference (SMD) values. We applied the new design to hospitalized older patients (aged ≥60 years) undergoing general surgery at four academic/teaching hospitals. Four datasets were analyzed: a base population before (Base Match-) and after (Base Match+) propensity-score matching to simulate previous observational studies; a study population before (Study Match-) and after (Study Match+) propensity-score matching to demonstrate effects of our design.

RESULTS

Of 6141 older patients, 662 (10.78%) were transfused and showed high heterogeneity compared with those not receiving transfusion, particularly regarding preoperative hemoglobin (mean: 11.0 vs. 13.5 g/dL) and intraoperative bleeding (≥500 mL: 37.9% vs. 2.1%). Patient heterogeneity was reduced with the new design; SMD of the two variables was reduced from approximately 100% (Base Match-) to 0% (Study Match+). Transfusion was related to a higher risk of death and complications in Base Match- (odds ratio [OR], 95% confidence interval [CI]: 2.68, 1.86-3.86) and Base Match+ (2.24, 1.43-3.49), but not in Study Match- (0.77, 0.32-1.86) or Study Match+ (0.66, 0.23-1.89).

CONCLUSIONS

We show how choice of study population and analysis could affect real-world study findings. Our results following the new design are in accordance with relevant RCTs, highlighting its value in accelerating the pace of transfusion evidence generation and generalization.