Emergency Patients with Iron Deficiency More Likely to Require Blood Transfusion

A new study has revealed a blood marker for patients with functional iron deficiencies, which are at higher risk for developing severe anemia and subsequently requiring a blood transfusion in the intensive care unit (ICU).

Researchers at Hospital Sant Joan de Deu (Manresa, Spain) and Hospital de Sabadell (Spain), conducted a prospective cohort study of 62 patients, after excluding those patients transfused on or before ICU admission. The researchers recorded age, diagnosis, reticulocyte hemoglobin content (CHr), severity score, presence of sepsis, ICU complications, ICU treatments, ICU and hospital outcomes, and transfusion-free interval. The threshold for low CHr was determined at 29 picograms.

The results showed that 23 out of the 65 patients (37%) presented with low CHr on ICU admission, and tended to be sicker and more likely to have sepsis than those with normal CHr. They were also more prone to complications, particularly acute renal failure, and ICU-acquired infection. The overall transfusion rate was 22.6%, being higher in low-CHr patients (39.1%) than in normal-CHr patients (12.8%). After adjusting for severity of illness, age, trauma, and hemoglobin level, low CHr remained significantly associated with transfusion, with a hazard ratio of 3.6; median ICU stay was also longer in patients with low CHr. The study was published in the May 2010 issue of Anesthesiology.

"The fact that iron deficiency was associated with a higher need for a transfusion and higher likelihood of mortality in this group should reinforce the impact iron levels can have on surgical outcomes,” said lead author Rafael Fernandez, M.D., Ph.D., of the ICU at Hospital Sant Joan de Deu. "Whenever possible, iron levels should be well-managed prior to admission.”

Because reticulocytes are the earliest erythrocytes released into blood, circulating for only one to two days, CHr provides a ready measure of iron available to red cells recently produced by the bone marrow. Low CHr figures indicate a possible lack of vitamin B12, folic acid, or iron in the diet, or an illness affecting the bone marrow. CHr has also been shown to be an early indicator of iron-restricted erythropoiesis in patients receiving erythropoietin therapy, and is a strong predictor of iron deficiency in children.

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Hospital Sant Joan de Deu
Hospital de Sabadell