PRBC Transfusion Threshold for Patients with Cardiac Disease

• As previously discussed, the PRBC transfusion threshold for the general population of critically ill patients is a Hgb < 7 gm/dL.
• Traditional teaching has been to maintain a Hgb > 10 gm/dL in patients with a history of CAD.
• This threshold stems from a 1950s cohort of Jehovah's Witness patients, and several observational studies, that demonstrated increased perioperative mortality in patients whose Hgb was < 10 gm/dL.
• Recent studies, however, have found that patients with a history of CAD tolerate lower Hgb levels without increases in morbidity or mortality.  In fact, current cardiovascular surgery guidelines favor a conservative Hgb threshold (7 gm/dL) for patients with CAD.
• Importantly, the Hgb threshold of < 7 gm/dL for PRBC transfusion applies to patients with simply a history of CAD and not to patients with evidence of an acute coronary syndrome (STEMI, NSTEMI, unstable angina).  Guidelines continue to recommend a Hgb > 10 gm/dL for patients with ACS.

References

Netzer G, Hess JR, Shanholtz C. Use of blood products in the intensive care unit: Concepts and controversies. Contemporary Critical Care June 2010;8(1):1-12.