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A recent study suggests that using smaller-volume collection tubes for blood draws in intensive care units (ICUs) might help reduce the occurrence of anemia and the necessity for red blood cell (RBC) transfusions. The research indicates that this change doesn’t compromise the adequacy of biospecimens for laboratory analysis.
By employing these smaller tubes, hospitals might decrease blood transfusions during ICU admissions by approximately 10 units per 100 patients. This reduction could aid in maintaining an adequate supply of blood products amid ongoing global shortages. Lead author Deborah Siegal, MD, a hematologist at the Ottawa Hospital and associate professor at the University of Ottawa, emphasized the substantial volume of blood typically drawn for lab work in hospitals, often leading to anemia and lower RBC counts among patients.
The study, published in JAMA on October 12, focused on ICU patients experiencing critical illness, where over 90% develop some level of anemia within three days of admission. The common practice of RBC transfusions aims to address low blood counts, with about 40% of ICU patients receiving at least one transfusion. However, both anemia and RBC transfusion correlate with adverse outcomes like increased mortality and prolonged hospital stays.
The need for frequent blood sampling contributes significantly to the blood volume drawn during ICU stays. Despite this, only a small portion—around 10%—is used for lab testing, with the rest discarded as waste. The study introduced smaller-volume tubes (1.8 to 3.5 mL), designed to draw about 50% less blood than standard-volume tubes (4 to 6 mL). These smaller tubes are of similar size, cost, and collection technique as standard ones but produce less waste. They were introduced in a trial across 25 adult medical-surgical ICUs in Canada between February 2019 and January 2021.
The research team assessed various factors including RBC transfusion rates, hemoglobin decrease during ICU stays, ICU and hospital lengths of stay, mortality rates, and specimen tubes with insufficient volume for testing. The primary analysis of over 21,000 patients didn’t show a significant difference in RBC units per patient per ICU stay between the tube-volume groups. However, a secondary analysis of over 27,000 patients demonstrated a significant decrease in RBC units per patient per ICU stay after the shift to small-volume tubes.
The study estimated that the use of smaller tubes potentially saved around 1500 RBC units out of approximately 36,000 units given to ICU patients during the study period. Siegal highlighted the potential impact of this change in conserving blood products for patients in need, including those undergoing cancer treatment, surgery, trauma, or other medical conditions.
However, some experts, like Lisa Hicks, MD, a hematologist at St. Michael’s Hospital and associate professor at the University of Toronto, suggest that while collecting smaller blood volumes seems feasible, the direct impact on reducing transfusions might be less certain due to various factors influencing hemoglobin levels in ICU patients.
The study underscores the potential benefits of implementing smaller-volume blood collection tubes in ICUs but also highlights the need for further research in different patient populations and settings to ascertain its broader efficacy.
