Information, tools, links and resources have been provided to implement the National Blood Authority perioperative patient blood management guidelines.
These resources can be adapted to suit your specific surgical service program and specific surgical target groups; for example, major joint surgery.
Anaemia should be viewed as a serious and treatable medical condition, rather than simply an abnormal laboratory value. Implementation of anaemia management and preoperative optimisation of Hb in the elective surgery setting will improve outcomes.
Preoperative anaemia assessment and red cell optimisation
Information, tools, links and resources are available to support the assessment of anaemia and the optimisation of red cell mass preoperatively. Tools designed by Blood Matters (available in the Downloads section) include:
- A quick audit tool designed to provide a snapshot of current anaemia assessment practice
- A checklist designed to assist the implementation of anaemia assessment in the elective surgical setting
- A business case template to assist the implementation of an anaemia clinic/process
Other tools include St Vincent’s Heath flow diagram of the process from referral to surgery, templates and Austin Health’s flow chart.
St Vincent’s Health process from referral to surgery
Template letter - Preoperative clinic review/Anaesthetic clinic preoperative blood testing
National Blood Authority preoperative haemoglobin assessment and optimisation template
Austin Health - Preoperative haemoglobin optimisation in Anaesthesia Preadmission Clinic (APAC) flow chart
Patients undergoing elective surgery with a preoperative haemoglobin (Hb) less than or equal to 120 g/L are at increased risk of blood transfusion. Anaemia, as defined by the World Health Organization, is an Hb level below 120 g/L in females and 130 g/L in males.
Previously undiagnosed anaemia is common in the setting of elective orthopaedic surgical patients and is associated with increased perioperative morbidity and mortality. It increases the likelihood of blood transfusion, which is independently associated with increased morbidity, mortality and hospital length of stay.
Currently 15-39 per cent of joint replacement patients are anaemic when assessed at pre-admission clinics. The prevalence varies, depending on age and associated comorbidities such as diabetes, congestive heart failure and other inflammatory conditions. Admission Hb levels have been shown to impact on post-operative functional recovery in the elderly population with hip fractures and on the quality of life after total hip arthroplasty.
Anaemia may be the result of serious underlying pathology
The aetiology of anaemia should be identified and, if necessary, patients referred for further investigation and treatment before referral for surgery.
If referred for further investigation, a thorough history and examination should be performed, along with assessment of red cell indices/blood film comments/reticulocyte count, and in comparison with any previous full blood count results.
Common causes of anaemia in older patients include iron deficiency (for example, due to chronic blood loss), Vitamin B12 or folate deficiency, anaemia of chronic disease/inflammation and chronic kidney disease.
Iron deficiency with or without anaemia is important
Iron deficiency anaemia may be effectively diagnosed in most cases by full blood count and ferritin.
Serum iron should NOT be used to diagnose iron deficiency. It is markedly labile, has diurnal variation and is also low in the presence of inflammation.
In the elderly or among patients with inflammation, iron deficiency may still be present with ferritin levels up to 60-100 ug/L.
Measurement of CRP may help identify co-existing inflammation. If uncertain, consult a haematologist. Clinicians need to be aware that numerous factors, often present in surgical patients, can inhibit or block iron absorption or iron availability for erythropoiesis.
Suboptimal iron stores
Non-anaemic patients undergoing surgery with significant blood loss may not have sufficient iron stores to recover their Hb post-operatively.
If a surgical procedure results in an Hb fall of 30-40 g/L, the predicted drop in ferritin would be 60-80 µg/L. If the patient’s preoperative ferritin is <100µg, iron stores would be insufficient to reconstitute their Hb loss and maintain normal iron stores.
Therefore, preoperative iron therapy may be indicated in the non-anaemic patients with a preoperative ferritin <100 µg/l and an anticipated post-operative Hb fall of >30 g/L (this is an average blood loss for major joint replacement).
Oral iron supplements
Oral iron preparations are available in both ferrous and ferric states. Ferrous salts are preferred as they are absorbed more readily.
Therapeutic doses of iron should increase haemoglobin levels by 0.7-1.0 g/dl per week.
Oral iron supplements must dissolve rapidly in the stomach so that the iron can be absorbed in the small intestine. Taking iron supplements with food can decrease iron absorption by as much as 60 per cent.
Vitamin C (ascorbic acid) is an enhancer of iron absorption and can reverse the effects of tea and calcium that can inhibit iron absorption.
South Australia’s Health’s BloodSafe tool outlines oral iron preparations for iron deficiency in Australia.
Failure of oral iron therapy
The primary reason for failure of oral iron therapy is poor compliance, often related to the gastrointestinal side effects such as nausea, vomiting, constipation, diarrhoea, dark-coloured stools and/or abdominal distress.
Minimise oral iron adverse effects
The following are strategies for minimising the adverse effects of oral iron:
- starting with half the recommended dose and gradually increasing to full dose
- taking the supplement in divided doses
- changing to a different iron preparation
- concomitantly using a stool softener to help alleviate constipation.
Good practice points - preoperative anaemia
Whenever clinically feasible, patients undergoing elective surgery with a high risk of severe post-operative anaemia should have their haemoglobin concentration and iron status tested, preferably at least 30 days before the scheduled surgical procedure.
Investigation and treatment of anaemia may decrease the risk of transfusion.
Unexplained anaemia should always be considered as secondary to some other process. If possible, elective surgery (especially for non-malignant disease) should be deferred until the anaemia is adequately evaluated and treated.
Blood conservation strategies
Strategies for conserving blood include the prevention of hypothermia, intra-operative cell salvage and the use of intravenous tranexamic acid.
Prevention of hypothermia
PBM guidelines Module 2: recommendation 12 prevention of hypothermia: In patients undergoing surgery, measures to prevent hypothermia should be used (Grade A). Currently there are no state or national Australian guidelines to inform practice. Best practice guidelines are available through the National Institute for Health and Clinical Excellence (United Kingdom).
Intraoperative cell salvage
PBM guidelines Module 2: recommendation 15 intraoperative cell salvage: In adult patients undergoing surgery in which substantial blood loss (blood loss of a volume great enough to induce anaemia that would require therapy) is anticipated, intraoperative cell salvage is recommended (Grade C).
PBM guidelines Module 2: recommendation 18 using medications (tranexamic acid): In adult patients undergoing non-cardiac surgery, if substantial (blood loss of a volume great enough to induce anaemia that would require therapy) is anticipated, the use of intravenous tranexamic acid is recommended (Grade B).
Tranexamic acid projects
Western Health is currently undertaking a project with the use of intravenous intra-operative tranexamic acid and major joint surgery.
Contact Susan McGregor
Transfusion Clinical Nurse Consultant
Fremantle Hospital can report on oral tranexamic acid with major joint surgery.
Contact Julie Tovey
Transfusion Clinical Nurse Consultant
Information and tools have been provided by the following organisations through the Blood Matters Perioperative Working Group: Austin Health, Ballarat Health Services, Djerriwarrah Health Service, Melbourne Health, Southern Health, St John of God Geelong, St Vincent’s Health, Western Health and Fremantle Hospital and Health Service.