>Pumping Iron! – IV Iron for Iron deficiency anemia in the ED

Pumping Iron! – IV Iron for Iron deficiency anemia in the ED

Resident Clinical Pearl – May 2016

Benoit Phelan, PGY3 iFMEM, Dalhousie University, Saint John, New Brunswick

Reviewed by Dr David Lewis

 

Clinical Question

Anemia is a common finding in patients presenting to the ED. How are we currently managing anemia in our ED? When do we transfuse with packed Red Blood Cells (pRBC)? If their hemoglobin is below 70 they need to be transfused, right? Not always….

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Packed RBC transfusion can and should be avoided in patients with Iron deficiency anemia but without significant on-going blood loss, and who are hemodynamically stable, asymptomatic at rest and tolerate normal activity (absence of CP, SOB, pre-syncope, hypotension and tachycardia). Reduced exercise tolerance is not an indication to transfuse with pRBC. Packed RBC transfusions are not benign. Acute life threatening (TACO, TRALI, AHTR) and irreversible long-term consequences due to allo-immunisation may arise.

See this article for more details on the complications of blood transfusion

 

An alternative and preferable option for this population is IV Iron infusion followed by a course of PO Iron. Parenteral Iron is indicated in the setting of poor oral tolerance, poor iron absorption, rate of blood loss exceeding the rate of absorption, severe anemia (Hb<90), and time constraints (preoperative).

 

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Most patients will require 1000mg of elemental iron to replete iron stores. Relying on GI absorption alone may not be favourable in certain populations. PPI use, gastric bypass, celiac disease, and high hepcidin levels may affect iron absorption in the GI tract. The GI tract’s maximum absorption is 66mg of elemental Iron daily. Higher doses such as TID regiments will not accelerate iron store repletion and may cause poorer adherence due to GI side-effects. Alone, a single dose of IV iron will not replete iron stores completely therefore it must be followed by subsequent parenteral doses or a PO regiment. In order to optimize GI absorption patient should be advised to take Iron supplements at bedtime on an empty stomach (2h after food) with Vit C, and avoiding Calcium and magnesium as these may impair absorption. Combination therapy may increase hemoglobin by 20-50g/L over 2 to 4 weeks beginning 3 to 7days after initiation.

 

IV Iron is safe but not without risk. Serious adverse events occur in <1 in 1 million infusions (1 in 200 000 in some reports). Historically, rates were much higher due to early high molecular weight iron dextran preparations. Hypotension occurs in 1-2% of infusion. Joint ache, muscle cramp, nausea, vomiting and diarrhea may occur in <1% of infusions and normally resolves in 12 to 24 hours. IV iron should not be used or be used cautiously in the setting of acute infection/sepsis (as it may promote bacterial growth), pregnancy, atop and systemic inflammatory disease.

 

The time required for infusion can be significantly shorter than that required for pRBC transfusion. Infusion rates vary with preparation types from 15 minutes (Feraheme) to 2 hours (Venofer). Slower infusion rates are required in the presence of hypotension, age >65, severe cardiac or respiratory disease, and multiple antihypertensive agents.

Bottom Line

Pumping IV Iron is a safe alternative to pRBC for Iron deficiency anemia. Should we be using it in our ED?

 

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References

  1. Schrier S.L., Auerbach M. (2016). Treatment of iron deficiency anemia in adults. In T. W. Post (Ed.), UpToDate. Retrieved from http://www.uptodate.com/contents/treatment-of-iron-deficiency-anemia-in-adults
  2. Helman, A. (2015). IV Iron for Anemia in Emergency Medicine. In Emergency Medicine Cases. Retrieved from http://emergencymedicinecases.com/iv-iron-for-anemia-in-emergency-medicine/
  3. Wright J.M. (2016). Intravenous (IV) iron for severe iron deficiency. In Therapeutic Letter, Therapeutic Initiative, UBCm Retrieved from http://www.ti.ubc.ca/2016/02/24/97-intravenous-iv-iron-for-severe-iron-deficiency/
  4. Rampton D, Folkersen J, Fishbane S, et al. Hypersensitivity reactions to intravenous iron : guidance for risk minimization and management. 2014;99(11):1671-1676. doi:10.3324/haematol.2014.111492.
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