Consolidating blood draws may help reduce blood loss in critically ill children
Research Activities, November 2012, No. 387
Critically ill children treated in the pediatric intensive care unit (PICU) are often subjected to frequent and routine blood draws. These can lead to blood loss and anemia. A new study has identified a number of ways this blood loss can be minimized, such as use of small-volume phlebotomy tubes and consolidating tests whenever possible. The study looked at 63 children who were admitted to a PICU at one institution. All stayed in the ICU for more than 2 days.
The researchers reviewed patients' charts to determine the type and number of lab tests performed per each blood draw. They also calculated the minimum amounts of blood needed for a particular test. The tests included blood gas, complete blood count, blood chemistry, and coagulation studies. The number of blood draws for each child averaged 2.7 per day. Such draws accounted for an average blood volume loss of 2.5 mL per each draw and totaled 34.0 mL for each PICU stay. The blood volume drawn in excess of lab requirements was 1.4 mL per draw. This resulted in an excess of 3.6 ml per day and 23 mL for the entire stay of the child in the PICU. These excesses represented 210 percent of the volume needed by the lab—a two fold increase—and a 110 percent overdraw. Blood draws were more likely to be overdrawn from a central venous catheter compared to arterial and peripheral intravenous catheters. Overdraws also occurred the most for one test compared to consolidated draws for 2, 3, and 4 tests. Blood drawn for a chemistry profile had the greatest chance of being overdrawn.
Recommendations for minimizing blood loss in these children include using small-volume tubes and closed system, consolidating tests, and taking advantage of adjunct monitoring to measure end-tidal CO2 and cerebral-mixed venous saturation. The study was supported in part by the Agency for Healthcare Research and Quality (T32 HS00063).
See "Identifying factors to minimize phlebotomy-induced blood loss in the pediatric intensive care unit," by Stacey L. Valentine, M.D., and Scot T. Bateman, M.D., in Pediatric Critical Care Medicine 13(1), pp. 22-27, 2012.