Impact of minimizing diagnostic blood loss in the critically ill

The use of a small-volume phlebotomy tube (SVPT) versus conventional-volume phlebotomy tube (CVPT) has led to a decrease in daily blood loss. Blood loss due to phlebotomy can lead ultimately to decreased rates of anemia and blood transfusions, which can be important in the critically ill patient.

We compared SVPT vs CVPT retrospectively in critically ill adult patients age ≥18 years admitted to a surgical intensive care unit for ≥48 hours. CVPT were evaluated from January 2011 to May 2011 and SVPT from June 2012 to October 2012.

Amount of blood drawn for laboratory tests and transfusions were evaluated in 248 patients (116 SVPT vs 132 CVPT). When compared with CVPT, total blood volume removed (mean ± SD) with SVPT was less overall, 174 ± 182 mL vs 299 ± 355 mL, P = .001. Daily blood draws also were less, 22.5 ± 17.3 mL vs 31.7 ± 15.5 mL, P < .001. The units of packed red blood cells given were not significant, 4.4 ± 3.6 units vs 6.0 ± 8.2 units, P = .16.

The use of SVPT blood sampling led to a decreased amount of blood drawn. Strategies that use SVPT in a larger cohort also may decrease the number of transfusions in selected patients. Every effort should be made to use SVPT.