Red Blood Cell Transfusion Practices in the Intensive Care Unit Vary Across Centers Worldwide

Among an international sample of patients admitted to intensive care units (ICUs) between 2019 and 2022, red blood cell (RBC) transfusion was common, with high variability in transfusion practices across centers, according to research published in JAMA.

“Multiple randomized clinical trials (RCTs) in various critically ill populations have suggested that a more restrictive transfusion regimen (ie, lower hemoglobin [Hb] level of 7 to 8 g/dL as threshold for RBC transfusion) is safe, and the latest guidelines reflect a restraint in RBC transfusion,” the study authors wrote in their report. “However, there is considerable uncertainty regarding the best strategies for transfusion management among different patient populations. Further uncertainty exists about current transfusion practice, and the clinical reasons and physiologic triggers that inform the decision to transfuse.”

To address this knowledge gap, the researchers conducted an international, prospective, cohort study to evaluate ICU RBC transfusion practices worldwide. The study took place between March 2019 and October 2022 and included adult patients in 30 countries on 6 continents.

The primary outcome was the occurrence of RBC transfusion during ICU stay. The team also assessed the indications or clinical reasons and physiological triggers for RBC transfusion, the stated Hb threshold and actual measured Hb values before and after an RBC transfusion, and the number of units transfused.

A total of 3643 patients across 233 ICUs, with a median of 11 patients per ICU (interquartile range [IQR], 5-20), were included in the study. Patients had a mean age of 61 years. The cohort was 62% male. The median length of stay was 3 days (IQR, 2-6), and the median Sequential Organ Failure Assessment score was 3.2 (IQR, 1.5-6.0).

Overall, 25% of patients received 1 or more RBC transfusions during their ICU stay. The median total number of transfusions was 2 units per patient (IQR, 1-4). The fraction of patients who received a transfusion ranged from 0% to 100% across centers, 0% to 80% across countries, and 19% to 45% across continents.

A total of 1727 RBC transfusions were administered. The most common clinical indications were low Hb value (81.8%), active bleeding (27.7%), and hemodynamic instability (23.5%). The most frequently stated physiological triggers were hypotension (42.2%), tachycardia (27.4%), and increased lactate levels (17.8%).

Most ICUs (84%) administered transfusions to patients with median Hb level greater than 7 g/dL. The mean lowest Hb before transfusion was 7.4 g/dL. The median lowest Hb level on days with an RBC transfusion ranged from 5.2 g/dL to 13.1 g/dL across centers, 5.3 g/dL to 9.1 g/dL across countries, and 7.2 g/dL to 8.7 g/dL across continents.

“To our knowledge, this study is one of the largest prospective cohorts designed to study this topic to date and the first study to provide an extensive overview of clinical reasons and physiological triggers that were used in the decision to transfuse,” the study authors explained. “The current study observed a wide range of stated clinical reasons and physiological triggers for transfusion. The European Society of Intensive Medicine transfusion guidelines advise to use Hb or hematocrit over alternative triggers, such as venous oxygen saturation, in nonbleeding patients, whereas in bleeding patients, alternative triggers and reasons are not mentioned at all.”

Limitations of the study were inclusion of mostly middle- to high-income countries, collection of transfusion variables only for patients who received 1 or more transfusions, no collection of data on race or ethnicity, no collection of hospital characteristics, and potential impact of the COVID-19 pandemic.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, or device companies. Please see the original reference for a full list of authors’ disclosures. 

Reference

Raasveld SJ, de Bruin S, Reuland MC, et al. Red blood cell transfusion in the intensive care unit. JAMA. Published online October 12, 2023. doi:10.1001/jama.2023.20737