3.4 Effect of non-transfusion interventions to increase haemoglobin concentration

3.4.1 Effect of iron therapy

A total of 13 studies of cardiac and noncardiac populations investigated the effects of iron therapy – either oral (8 studies), intravenous (3 studies) or oral versus intravenous (2 studies) – on morbidity, mortality or the need for blood transfusion. Of these, 8 were Level II (of which 2 were of good quality) and 5 were Level III (all of fair quality).

Interpretation of the evidence base was difficult because of variable definitions of anaemia, lack of categorisation of the cause of anaemia, and differences in treatment doses and schedules.

Preoperative oral iron therapy given to noncardiac surgery patients who were anaemic preoperatively was associated with an increase in haemoglobin,95,96 and a reduction in transfusion requirements.95–97 There were no studies of preoperative iron therapy in an anaemic cardiac surgical population; however, it is reasonable to expect that the findings would be similar.

The effect of postoperative oral iron was investigated in patients found to be anaemic postcardiac98–100 and noncardiac surgery.101,102 The effect on haemoglobin concentration was minimal. This finding is not unexpected, because the acute inflammatory response after surgery is associated with reduced iron absorption.

The only study of postoperative intravenous (IV) iron administration in a noncardiac surgery population showed a significant reduction in the number of units of blood transfused postoperatively per patient.103

Patients who are at risk of significant blood loss or preoperative anaemia should have their haemoglobin and iron stores assessed. In patients with iron deficiency anaemia or suboptimal iron stores (defined by a ferritin level of <100 μg/L), preoperative iron therapy is suggested. Preoperative assessment should be performed as early as possible, to allow an adequate course of treatment. The choice of iron therapy will depend on individual clinical assessment, taking into account the haemoglobin level, the nature and urgency of surgery, and the patient’s ability to tolerate and comply with therapy. See the preoperative haemoglobin assessment and optimisation template (Appendix F) for guidance. The template was developed by consensus; use of an algorithm should always take into account the patient’s history and clinical assessment, and the nature of the proposed surgical procedure.