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The clinical utility of an index of global oxygenation for guiding red blood cell transfusion in cardiac surgery
Author(s) -
Orlov David,
O'Farrell Rachel,
McCluskey Stuart A.,
Carroll Jo,
Poonawala Humara,
Hozhabri Siroos,
Karkouti Keyvan
Publication year - 2009
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/j.1537-2995.2008.02022.x
Subject(s) - medicine , cardiopulmonary bypass , cardiac surgery , oxygenation , blood transfusion , hemoglobin , anesthesia , cardiology , surgery
BACKGROUND: This observational study explored the potential utility of oxygen extraction ratio (O 2 ER) as an adjunct to the hemoglobin (Hb) concentration for guiding red blood cell (RBC) transfusion decisions after cardiac surgery with cardiopulmonary bypass (CPB). STUDY DESIGN AND METHODS: Hb and O 2 ER measures were obtained before as well as 15 and 120 minutes after RBC transfusion episodes (defined as 1‐2 RBC units given in succession after CPB, within 24 hr of surgery). Changes related to RBC transfusions among patients with normal (≤30%) and elevated (>30%) pretransfusion O 2 ERs were analyzed. RESULTS: Of the 176 patients enrolled, 74 received RBC transfusions. Of these, 50 had data available for 62 transfusion episodes. Pretransfusion episode O 2 ER values were elevated in 27 cases and normal in 35 (56%) cases. Among those who received transfusion for low Hb concentration, 43 percent (27/62) had normal pretransfusion O 2 ER values. While the posttransfusion O 2 ER values did not change in patients with normal pretransfusion O 2 ER values, they did decrease in patients with elevated pretransfusion O 2 ER values (% change [±SD] at 15 and 120 min after transfusion was −5.2 ± 7.8 and −3.8 ± 8.0%, respectively; p < 0.05). CONCLUSION: If a normal O 2 ER in anemic patients with no evidence of organ dysfunction indicates adequate tissue oxygen delivery, then our findings suggest that incorporating O 2 ER into the transfusion decision will substantially reduce postcardiac surgery RBC transfusions by allowing us to safely avoid transfusing this group of patients. Future studies are needed to assess the validity of this conclusion.