General Critical Care

The Restrictive Red Blood Cell Transfusion Strategy for Critically Injured Patients (RESTRIC) trial: a cluster-randomized, crossover, non-inferiority multicenter trial of restrictive transfusion in trauma

This study, known as the Restrictive Transfusion Strategy for Critically Injured Patients (RESTRIC) trial, was designed to investigate the efficacy of red blood cell (RBC) transfusion in patients with severe trauma. Given the uncertainties surrounding optimal hemoglobin target levels during the acute post-injury phase, the trial set out to determine whether a restrictive transfusion strategy would prove clinically non-inferior to a liberal one.

The study involved a cluster-randomized, crossover, non-inferiority design across 22 tertiary emergency medical institutions in Japan. Participants included adult patients at risk of major bleeding from severe trauma. The institutions implemented either a restrictive (hemoglobin targets of 7–9 g/dL) or liberal (hemoglobin targets of 10–12 g/dL) transfusion strategy, immediately upon the patients' arrival in the emergency department.

The primary outcome observed was the 28-day survival post-arrival at the emergency department, while secondary outcomes included transfusion volume, complication rates, and event-free days.

The results revealed similar 28-day survival rates between the restrictive (92.1%) and liberal (91.3%) strategy groups. The adjusted odds ratio for 28-day survival in the restrictive vs. liberal strategy group was 1.02. However, significant non-inferiority was not observed. Interestingly, the restrictive strategy resulted in lower transfusion volumes and hemoglobin levels.

Ultimately, the study concluded that while the restrictive transfusion strategy didn't demonstrate statistically significant non-inferiority for 28-day survival, it yielded similar mortality and complication rates with the added benefit of reduced transfusion volumes.

Perspective

This study offers important insights into the ongoing debate on optimal RBC transfusion strategies in the context of severe trauma. The results suggest that a restrictive transfusion strategy is comparable to a liberal one in terms of 28-day survival rates, complication rates, and event-free days. Moreover, the restrictive strategy brings the added benefit of reduced transfusion volumes, which could potentially lower risks associated with blood product overuse.

However, we must exercise caution in interpreting these findings. Despite the apparent benefits, the restrictive strategy did not demonstrate statistical non-inferiority, hinting at the possibility of Type II error due to the underpowered nature of the trial. Additionally, the absence of blinding and potential bias might have influenced the outcomes. Further research is needed to substantiate these findings, and to help define the ideal hemoglobin threshold levels for initiating transfusion in trauma patients.

In conclusion, while the study does not provide definitive evidence favoring a restrictive transfusion strategy, it certainly encourages us to reconsider our practices in severe trauma management, prompting us to ask the right questions and further our pursuit of evidence-based practices.

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The Restrictive Red Blood Cell Transfusion Strategy for Critically Injured Patients (RESTRIC) trial: a cluster-randomized, crossover, non-inferiority multicenter trial of restrictive transfusion in trauma | Journal of Intensive Care | Full Text (biomedcentral.com)