Lower Versus Higher Hemoglobin Threshold for Transfusion in Septic Shock

Study Questions:

What are the effects on mortality of leuko-reduced blood transfusion at a lower versus a higher hemoglobin threshold among patients with septic shock who are in the intensive care unit (ICU)?

Methods:

In this multicenter, parallel-group trial, the investigators randomly assigned patients in the intensive care unit (ICU) who had septic shock and a hemoglobin concentration of ≤9 g/dl to receive 1 unit of leuko-reduced red cells when the hemoglobin level was ≤7 g/dl (lower threshold) or when the level was ≤9 g/dl (higher threshold) during the ICU stay. The primary outcome measure was death by 90 days after randomization.

Results:

The investigators analyzed data from 998 of 1,005 patients (99.3%) who underwent randomization. The two intervention groups had similar baseline characteristics. In the ICU, the lower-threshold group received a median of 1 unit of blood (interquartile range, 0-3) and the higher-threshold group received a median of 4 units (interquartile range, 2-7). At 90 days after randomization, 216 of 502 patients (43.0%) assigned to the lower-threshold group, as compared with 223 of 496 (45.0%) assigned to the higher-threshold group, had died (relative risk, 0.94; 95% confidence interval, 0.78-1.09; p = 0.44). The results were similar in analyses adjusted for risk factors at baseline and in analyses of the per-protocol populations. The numbers of patients who had ischemic events, who had severe adverse reactions, and who required life support were similar in the two intervention groups.

Conclusions:

The authors concluded that among patients with septic shock, mortality at 90 days and rates of ischemic events and use of life support were similar among those assigned to blood transfusion at a higher hemoglobin threshold and those assigned to blood transfusion at a lower threshold.

Perspective:

This study reports no significant differences in mortality at 90 days, in the numbers of patients with ischemic events or with severe adverse reactions, in the use of life support, or in the numbers of days alive and out of the hospital between the group of patients who underwent transfusion at a lower hemoglobin threshold and the group of those who underwent transfusion at a higher hemoglobin threshold. Although no harm was noted with an excess transfusion of a median of 3 units of blood, no benefits were seen either, and routine transfusion at higher hemoglobin threshold cannot be recommended.

Clinical Topics: Diabetes and Cardiometabolic Disease

Keywords: Blood Transfusion, Shock, Septic, Outcome Assessment (Health Care), Intensive Care Units, Hemoglobins, Erythrocytes, Risk Factors


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