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Total plasma heme concentration increases after red blood cell transfusion and predicts mortality in critically ill medical patients
Author(s) -
Pietropaoli Anthony P.,
Henrichs Kelly F.,
Cholette Jill M.,
Spinelli Sherry L.,
Phipps Richard P.,
Refaai Majed A.,
Blumberg Neil
Publication year - 2019
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/trf.15218
Subject(s) - interquartile range , heme , medicine , hemoglobin , blood transfusion , red blood cell , intensive care unit , odds ratio , critically ill , gastroenterology , chemistry , biochemistry , enzyme
BACKGROUND Relationships between red blood cell (RBC) transfusion, circulating cell‐free heme, and clinical outcomes in critically ill transfusion recipients are incompletely understood. The goal of this study was to determine whether total plasma heme increases after RBC transfusion and predicts mortality in critically ill patients. STUDY DESIGN AND METHODS This was a prospective cohort study of 111 consecutive medical intensive care patients requiring RBC transfusion. Cell‐free heme was measured in RBC units before transfusion and in the patients' plasma before and after transfusion. RESULTS Total plasma heme levels increased in response to transfusion, from a median (interquartile range [IQR]) of 35 (26–76) μmol/L to 47 (35–73) μmol/L (p < 0.001). Posttransfusion total plasma heme was higher in nonsurvivors (54 [35–136] μmol/L) versus survivors (44 [31–65] μmol/L, p = 0.03). Posttransfusion total plasma heme predicted hospital mortality (odds ratio [95% confidence interval] per quartile increase in posttransfusion plasma heme, 1.76 [1.17–2.66]; p = 0.007). Posttransfusion total plasma heme was not correlated with RBC unit storage duration and weakly correlated with RBC unit cell‐free heme concentration. CONCLUSIONS Total plasma heme concentration increases in critically ill patients after RBC transfusion and is independently associated with mortality. This transfusion‐associated increase in total plasma heme is not fully explained by RBC unit storage age or cell‐free heme content. Additional studies are warranted to define mechanisms of transfusion‐related plasma heme accumulation and test prevention strategies.