Transfusion Practices in the Intensive Care Unit

During the past 2 decades, transfusion practices in the intensive care unit (ICU) have evolved. Based on the results of randomized trials, guidelines recommend deferring transfusion of red blood cells (RBC) until hemoglobin is <7 g/dL in most ICU patients (NEJM JW Gen Med Nov 15 2023 and JAMA 2023 Oct 12; [e-pub]). In two studies, researchers examined practices related to this guidance.

In one study, investigators tracked the RBC transfusion practices for nearly 4000 ICU patients at 233 medical centers in 30 countries (mostly high or middle income). One third of patients were admitted electively, most often for postoperative monitoring; median length of stay was 3 days. About 85% of patients were anemic during their ICU stay, and one quarter of patients received RBC transfusions (most commonly postoperatively). The likelihood of transfusion varied widely across countries. The most common reasons for transfusion were low hemoglobin level or hypotension. Median hemoglobin was <7g/dL at the time of transfusion in only 16% of ICUs.

A study in Canadian ICUs focused on use of small-volume blood collection tubes to lower need for transfusion. Twenty-five ICUs transitioned from using standard tubes (4–6 mL) to small-volume tubes (1.8–3.5 mL). Among the 18 ICUs that entered the study prior to the COVID-19 pandemic, a reduction in RBC transfusions after transition to small tubes (7 fewer units/100 patients per ICU stay) did not reach statistical significance. However, in the full 25-ICU analysis (which included 7 ICUs that entered the study during the pandemic), the reduction in transfusions after transitioning to small tubes was significant (10 fewer units/100 patients per ICU stay; P=0.04). Only very rarely did a small-volume tube contain insufficient blood for the studies ordered.