115 blood tests per heart patient: In-hospital draws draining them dry

A study revealed that in one hospital, cardiac surgery-related phlebotomy was really draining its patients. Analyzing a possible link between blood draws and hospital-acquired anemia, researchers found that 74 percent of patients with normal values for hemoglobin on admission were anemic by discharge.

Researchers from the Cleveland Clinic reviewed rates and types of laboratory testing for cardiac surgery patients from January through June 2012. A total of 1,894 patients underwent surgery; most had one hospitalization, 27 had two. Colleen G. Koch, MD, MS, of the cardiothoracic anesthesia department, and colleagues assessed cumulative phlebotomy volumes that included seven to 10 mL of discarded blood from line clearing.

An average of 115 tests were performed per patient. Most frequent tests were blood gas analysis (88,068), coagulation tests (39,535), complete blood counts (30,421) and metabolic panels (29,374). On average, 332 mL of blood were taken during stays in the cardiovascular intensive care unit and 118 were taken on care floors. Average cumulative volume taken for the entire hospital stay was 454 mL, with the maximum volume taken around 16,021 mL over the course of one patient’s 2.5-month hospitalization.

More complex surgeries meant more blood taken: median phlebotomy volumes for combined CABG and valve procedures were 653 mL; isolated CABG or valve procedures were significantly lower, 448 and 338 mL, respectively. Longer stays also equated to more phlebotomy draws.

As a result, 49 percent of patients required red blood cell transfusions, 33 percent needed platelets, 25 percent required fresh frozen plasma and 15 percent needed cryoprecipitate.

Koch et al found several areas contributed to the overall volume of bloodletting, including lack of in-line blood conservation devices and communication between care staff about the frequency of daily testing. Based on these findings, the Cleveland Clinic began changing processes, including modifications which reduced discard volumes from 7 to 10 mL to 3 mL and providing cumulative tallies of phlebotomy volumes per patient to provide clinicians a better understanding of ongoing laboratory testing.

“Implementation of process improvement initiatives with careful monitoring should result in reduced phlebotomy volumes, better use of limited resources, and improved patient outcomes,” Koch et al wrote.

The study was published in the March issue of Annals of Thoracic Surgery.