Effects of Rapid Administration of Iron Polymaltose in Patients with Anaemia, Under General Anaesthesia for Routine Surgery. “The RAPID Trial”

Aim We aim to show that giving intravenous iron polymaltose over 10 minutes to patients who are under general anaesthesia is convenient, safe and not associated with a significant incidence of low blood pressure or other adverse effects. Background - Anaemia and iron deficiency are very common in surgical patients. A recent audit at KEMH, the tertiary womens hospital in WA, showed that 18% of women were anaemic prior to their gynaecological surgery. In patients undergoing surgery anaemia has been linked with an increased risk of needing a blood transfusion, slower recovery from surgery and an increase in postoperative complications. Patients often suffer from decreased energy, fatigue and poor ability to concentrate, all of which will affect their quality of life. - Iron polymaltose is an intravenous iron medication commonly used to correct anaemia and iron deficiency. It has been used in Australia for over 40 years, has a very good safety record and about 4-500 women a year receive iron polymaltose at KEMH currently. It is usually administered as a slow infusion over 2 - 3 hours in a general ward setting. Common adverse effects can include headache, nausea, flushing, low blood pressure and muscle cramps all of which are not as relevant to patients whilst they are under general anaesthesia. Serious adverse events such as anaphylaxis are extremely rare and are not related to the speed at which iron polymaltose is given. - Oral iron tablets are not effective in many patients for a number of reasons. It would labour intensive, expensive and inconvenient to bring all these patients back to a ward for a 1-2 hour infusion of iron polymaltose after surgery. Other intravenous iron preparations, with similar pharmacological properties, have been shown to be safe when given over similar short periods of time and we believe this will be the case with iron polymaltose too. Some anaesthetists (in Australia and NZ) have already administered iron polymaltose in this manner with no anecdotal reports of any problems, however we believe it warrants formal evaluation. Study Design and Methods We aim to recruit 100 patients with iron deficiency anaemia or iron deficiency who are scheduled to undergo general anaesthesia for an elective surgical procedure. Routine care will be unaffected and they will receive general anaesthesia as they would if they were not involved in this trial. Following commencement of surgery and during a period of haemodynamic stability (as assessed by the responsible anaesthetist), they will receive an iron polymaltose infusion over a 10 min period and we will collect data on any adverse effects and change in blood pressure over this time. In order to assess the haemodynamic impact of the infusion, any changes in blood pressure will be compared to the decrease in blood pressure seen at the start of the anaesthetic. Outcomes Primary outcome will be the incidence of significant low blood pressure following the administration of iron polymaltose (definition = systolic BP less than 80mmHg or blood pressure treatment required). Secondary outcomes, will be the incidence of all adverse effects as ascertained by questionnaire 2 hours after surgery and changes in blood markers of iron deficiency. Potential Benefits / Ethical Issues The current drug manufacturers product information sheet, recommends a slow infusion of iron polymaltose over approximately 4.5 hours, however most WA hospitals already administer iron polymaltose over a shorter periods of time, with no serious problems. We believe that if we demonstrate this technique of administration is safe it may lead to more effective & widespread treatment of iron deficiency and anaemia in surgical patients