Anaemia is present in over 30 percent of patients who have major surgery. It is associated with worse outcomes, including poorer wound healing, slower mobilisation and an increased risk of death.
Anaemia is an independent risk factor associated with a 20 percent increase in post-operative complications. This not only has a personal cost to the patient, in terms of outcomes and experience, but also a financial cost to the trust or health board in terms of transfusion rates and length of stay.
The newly published Guideline for Management of Anaemia in the Perioperative Pathway by the Centre for Perioperative Care (CPOC) seeks to improve patient outcomes by collating existing speciality guidelines, expert opinion and examples of good practice into one whole-pathway guideline applicable to patients of all ages undergoing elective and emergency surgery.
As with other CPOC guidelines, the working group had cross-speciality representation, including UKCPA representation, ensuring the content is relevant to all healthcare professionals involved in the care of a surgical patient.
The guideline consists of recommendations (for healthcare professionals, patients, carers and commissioning bodies), explanations of underpinning concepts, and resources to facilitate implementation (such as patient information leaflets and template letters).
We’ve highlighted the key messages for pharmacists involved in the care of surgical patients.
Early screening, early diagnosis, early treatment
All patients referred for major surgery should have full blood count checked at the point of referral, or at first surgical consultation, to screen for anaemia (providing they fulfil the NICE preoperative testing criteria). Early detection of anaemia enables early investigations into the type of anaemia and maximises the time available for optimisation.
Commencing treatment early in the pathway increases the treatment options as otherwise there may be insufficient time to use oral iron. Early action also facilitates discussions with the patient about the risks and benefits of untreated anaemia. This results in timely shared decision making about whether to defer surgery to investigate and optimise anaemia, rather than last minute decisions which potentially compromise outcomes due to lack of optimisation or theatre utilisation due to short notice cancellations.
Think and act on 130
Haemoglobin less than 130g/L warrants further investigation, to determine the type of anaemia, and treatment, regardless of gender. Historically, anaemia was defined as haemoglobin less than 120g/L in women and less than 130g/L in men; however, there is growing opinion, supported by an international consensus statement, that 120g/L is suboptimal and contributes to worse outcomes.
Women have a smaller circulating blood volume than men and therefore lose proportionately more blood volume for the same actual blood loss. This increases the risk of transfusion and postoperative complications.
Ferritin, CRP and transferrin saturation, not MCV and MCH
Iron deficiency is the most common cause of anaemia but there is no single diagnostic test. Mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH) cannot be relied on to diagnose, or exclude, iron deficiency as they are normal in up to 40 percent of patients with iron deficiency anaemia. Instead, diagnosis should be based on clinical history and interpretation of a number of laboratory tests such as ferritin, C-reactive protein (CRP) and transferrin saturation.
Ferritin is an acute phase protein and is elevated in chronic inflammatory states. When interpreting ferritin levels it is important to consider the context; if CRP is elevated or renal function is impaired, normal or high ferritin levels may occur, even in iron deficiency. The CPOC guideline contains a helpful flow chart to aid with interpreting tests results to determine the type of anaemia and the correct treatment.
Reduce the hepcidin effect
Hepcidin is released in the presence of iron and reduces gastrointestinal absorption of iron. Traditional multiple daily dose oral iron supplements are poorly absorbed and poorly tolerated due to diarrhoea and constipation (likely because of the continuing presence of unabsorbed iron in the gastrointestinal tract).
Once daily or alternate day dosing of iron supplements allow hepcidin levels to fall, maximising absorption and improving tolerability. Whilst single daily dosing of 40-60mg elemental iron, or alternate day dosing of 80-100mg elemental iron, was recommended in the Munoz et al. international consensus statement, pragmatically CPOC recommends using any commercially available iron preparation at a dose of either one tablet once a day or one to two tablets on alternate days.
Oral or intravenous?
Intravenous iron is recommended when there is insufficient time for oral iron to be effective (ie less than four weeks until surgery), when oral iron is not tolerated, when there is no response to four weeks of oral iron, or in emergency settings.
Hepcidin levels are elevated in the presence of inflammation (such as the immediate post-operative period), making oral iron less effective. However, the guideline notes that the current evidence for intravenous iron following surgery is weak.
Hepcidin is also implicated in the pathophysiology of functional iron deficiency (previously known as anaemia of chronic disease), which is associated with chronic inflammatory comorbidities such as autoimmune disease, chronic kidney disease and malignancy. Therefore intravenous iron treatment may be necessary in this situation.
What now?
In summary, anaemia is common and associated with an increased risk of perioperative complications, and yet it is a modifiable risk factor. Small but important changes in the approach to anaemia by all members of the multidisciplinary team will cumulatively lead to improvements in patient care, outcomes and safety.
To help you implement these guidelines and improve patient care, download the
Guideline for Management of Anaemia in the Perioperative Pathway and don’t forget to check out the appendices which feature practical implementation tools which were shared by UKCPA members.
The opinions expressed in this article are those of the author. They do not purport to reflect the opinions or views of the UKCPA or its members. We encourage readers to follow links and references to primary research papers and guidance.
