Contemporary bloodletting in cardiac surgical care

Health care providers are seldom aware of the frequency and volume of phlebotomy for laboratory testing, bloodletting that often leads to hospital-acquired anemia. Our objectives were to examine the frequency of laboratory testing in patients undergoing cardiac surgery, calculate cumulative phlebotomy volume from time of initial surgical consultation to hospital discharge, and propose strategies to reduce phlebotomy volume.

From January 1, 2012 to June 30, 2012, 1,894 patients underwent cardiac surgery at Cleveland Clinic; 1,867 had 1 hospitalization and 27 had 2. Each laboratory test was associated with a test name and blood volume. Phlebotomy volume was estimated separately for the intensive care unit (ICU), hospital floors, and cumulatively.

A total of 221,498 laboratory tests were performed, averaging 115 tests per patient. The most frequently performed tests were 88,068 blood gas analyses, 39,535 coagulation tests, 30,421 complete blood counts, and 29,374 metabolic panels. Phlebotomy volume differed between ICU and hospital floors, with median volumes of 332 mL and 118 mL, respectively. Cumulative median volume for the entire hospital stay was 454 mL. More complex procedures were associated with higher overall phlebotomy volume than isolated procedures; eg, combined coronary artery bypass grafting (CABG) and valve procedure median volume was 653 mL (25th/75th percentiles, 428 of 1,065 mL) versus 448 mL (284 of 658 mL) for isolated CABG and 338 mL (237 of 619) for isolated valve procedures.

We were astonished by the extent of bloodletting, with total phlebotomy volumes approaching amounts equivalent to 1 to 2 red blood cell units. Implementation of process improvement initiatives can potentially reduce phlebotomy volumes and resource utilization.