Is parenteral iron indicated?
Once iron deficiency is diagnosed, establish the cause. The decision on appropriate treatment should then consider the patient’s treatment goals. This includes assessing the options for correcting the iron deficiency and their potential adverse effects. Dietary intake, oral supplements or parenteral iron are suitable options.3
Parenteral iron is usually only indicated when oral iron therapy has failed.3 However, there are some patient cohorts who may benefit from intravenous iron without a trial of oral therapy. They include patients who have heart failure with a reduced ejection fraction,15 those undergoing haemodialysis,17 and pregnant women in their second or third trimester requiring rapid iron replenishment.18
Inform patients about skin staining
Although the incidence of iron staining appears to be relatively low, its potential irreversibility and the cosmetic impact it may have warrant discussion with patients. The Medical Board of Australia has reminded medical practitioners to advise patients about the risk so that they can give informed consent to treatment.19 Using a patient information brochure about iron staining may assist with this. The BloodSafe organisation has a useful leaflet available in English and other languages.20 When intravenous iron is indicated and patients choose to receive an infusion, it is advisable to document the content and outcome of the discussion about risks including discolouration or staining.
Correct injection site and infusion technique
The infusion sites used for intravenous therapy may influence the rate of extravasation due to the potential for vessel damage related to movement of the cannula.21,22 Administration of intravenous iron via cannulation at sites of flexion (e.g. antecubital fossa, wrist) or on the back of the hand should be avoided when possible. If these sites must be used, the smallest suitable cannula size may reduce the likelihood of vessel trauma.22 Try to minimise catheter movement by securing the cannula21-23 and using an extension set.24 When using smaller gauge devices, it may be necessary to slow the infusion to minimise the risk of dislodgement.25
The number of attempts at cannulation should be minimised as there is an increased risk of extravasation due to multiple venous punctures.21,22 For patients who are difficult to cannulate, seek the expertise of more experienced staff. Although postponing intravenous iron therapy may inconvenience the patient, it is unlikely to result in adverse clinical outcomes. Intravenous iron infusion is rarely urgent.
The patency of the cannula should be checked by giving 5–10 mL of sodium chloride 0.9% before the infusion.21
Monitor for extravasation
The review of cutaneous pigmentation reported to the French pharmacovigilance database suggested improvements in monitoring are necessary to detect extravasation.12 Patients who experience iron extravasation resulting in staining may describe pain, swelling, and feelings of pressure or pricking at the infusion site.13 Patients should therefore be told to notify staff of any of these symptoms (Box 3). This is an important consideration for patients who do not understand English. Administration of intravenous iron must be avoided if the patient’s ability to report these symptoms is reduced (e.g. anaesthetised patients). Early cessation of the infusion may limit the amount of solution that enters the tissues and could minimise the extent of staining.