(http://emergencymedicinecases.com/wp-content/uploads/2015/05/IV-iron-transfusion-300.jpg)For years we’ve been transfusing red cells in the ED to patients who don’t actually need them. A study looking at trends in transfusion practice in the ED found that about 1/3 of transfusions given were deemed totally inappropriate. As we explained in previous EM Cases episodes, there have been a whole slew of articles in the literature over the years that have shown that morbidity and mortality outcomes with lower hemoglobin thresholds, like 70g/L for transfusing ICU patients (TRICC trial), patients in septic shock (TRISS trial), and patients with GI bleeds are similar to outcomes with traditional higher hemoglobin thresholds of 90 or 100g/L. We’re simply transfusing blood way too much! The American Association of Blood Banks in conjunction with the American Board of Internal Medicine’s Choosing Wisely campaign, as one of its 5 statements on overuse of procedures, stated, “don’t transfuse iron deficiency without hemodynamic instability”.

So, in this episode with the help of Transfusion specialist, researcher and co-author of the American Association of Blood Banks transfusion guidelines Dr. Jeannie Callum, Transfusion specialist and researcher Dr. Yulia Lin, and 'the walking encyclopedia of EM'  Dr. Walter Himmel, we give you an understanding of why it’s important to avoid red cell transfusions in certain situations, why IV iron is sometimes a better option in a significant subset of anemic patients in the ED, and the practicalities of exactly how to administer IV iron.

Written Summary and blog post prepared and written by Dr. Michael Kilian, edited by Dr. Anton Helman
Menorrhagia and IV Iron for Anemia in Emergency Medicine
Case 1

ID: 49 year old woman sent in by her family physician with a note indicating “severe menorrhagia for several months and hemoglobin 57 g/L; please transfuse”.

PMH: Nil

HPI: Decreased exercise tolerance with increasingly heavy periods for several months. She denies dizziness or syncope.

O/E: Vitals and exam all within normal limits

How would you manage this patient’s anemia?

 
Is severe anemia unsafe in healthy people?
In a study of healthy subjects from JAMA in 1998 entitled ‘Human Cardiovascular and Metabolic Response to Acute Severe Isovolemic Anemia’, in which aliquots of blood (450-900 mL) were removed to reduce blood hemoglobin concentration from 131g/L to 50 g/L and isovolemia was maintained with 5% human albumin and/or autologous plasma, they found that acute isovolemic reduction of blood hemoglobin concentration to 50 g/L did not produce evidence of inadequate systemic “critical” oxygen delivery, as assessed by lack of change of O2 and plasma lactate concentration. Analysis of Holter readings suggested that at this hemoglobin concentration in this resting healthy population, myocardial ischemia would occur infrequently.

Compensation in chronic vs acute anemia
Patients with chronic anemia can adjust physiologically to anemia even more readily than patients with acute anemia because of the shift in the oxygen dissociation curve. This is facilitated by a change in the 2,3-DPG level allowing the RBCs to be 'less selfish' so they can more easily offload oxygen to the tissues. As such, a hemoglobin of 50g/L can be considered as physiologically higher than it appears in patients with chronic anemia.

 
The WOMB Trial showed that young women can safely tolerate a hemoglobin as low as 50g/L
The WOMB trial was a multi-centered Dutch trial that enrolled 521 women with severe postpartum anemia (hemoglobin 48 to 79 g/L) who were randomized to transfusion or transfusion only if they developed severe symptoms. It found no differences in any important outcomes (recovery of hemoglobin, 6 week hemoglobin). There was, however, a non-clinically significant difference in fatigue scores at 7 days that was not persistent at later time point.