Patients in the intensive care unit (ICU) often have multiple blood draws daily, which typically amount to approximately one unit of blood every eight days. Standard blood collection tubes use a calibrated vacuum to withdraw between 4 and 6 mL of blood, but most modern laboratory tests require a very small volume (usually <0.5 mL). Thus, researchers aimed to determine if small-volume blood collection tubes in the ICU would decrease RBC transfusions without disrupting laboratory tests. In a cluster randomized controlled trial in Canada, 25 ICUs transitioned to small-volume blood collection tubes in a step-wise fashion for the duration of the study for all adult ICU patients. Based on primary data from 27,411 patients (ICU stay >48 hours; 30% received at least one RBC transfusion), the least squares mean number of RBC units transfused per patient was 0.80 (95% C.I., 0.61 to 1.06) for standard sized collection tubes and 0.71 (95% C.I., 0.53-0.93) after transition to small-volume collection tubes (RR, 0.88 [95% C.I., 0.77 to 1.00]; p=0.04). Importantly, the number of samples flagged for insufficient quantity for analysis did not increase after transitioning to small-volume collection tubes. Small-volume blood collection tubes for patients in the ICU may reduce RBC transfusions without increasing cost or affecting laboratory analysis.Reference:
