Date Published: 
Wednesday, 27 August, 2014

Risk of transfusion and postoperative morbidity in fast-track total hip and knee arthroplasty

Professor Manuel Muñoz

Patients scheduled for major elective orthopaedic procedures frequently present with preoperative iron deficiency and anaemia1,2. Iron deficiency anaemia is the most common form of anaemia and preoperative anaemia has been linked to higher postoperative infection rate, poorer physical functioning and recovery, decreased quality of life, and increased length of hospital stay (LOS) and mortality1–5. In addition, preoperative anaemia, and suboptimal haemoglobin concentration (<13 g/dL), is a major independent predictive factor for perioperative allogeneic blood transfusion (ABT) in patients undergoing major orthopaedic procedures6–8. This, in turn, is associated with increased mortality, morbidity, and resource use, highlighting that caution is necessary in ABT patients who are mildly hypovolaemic, anaemic or iron deficient9.

Recently, Jans and colleagues analysed a prospective observational database with data obtained from six high-volume Danish surgical centres. Prevalence of preoperative anaemia, and its association with risk of perioperative ABT, prolonged LOS, and postoperative readmission, was assessed in over 5,000 elective fast-track total hip (THA) and total knee arthroplasty (TKA) procedures10. The authors stated that “the main finding of this study was that preoperative anaemia is prevalent before elective fast-track THA and TKA and is associated with increased risk of receiving ABT during admission and risk of prolonged LOS and readmission”. The study highlights the impact of preoperative anaemia on patient outcome in surgical practice and the importance of anaemia correction prior to surgery.

Anaemia was present in 12.8% of procedures. Overall, 11% received ≥1 transfusion during primary admission, but anaemic patients were at a 4-fold higher risk for transfusion compared with non-anaemic patients (32 vs 8.1%; p>0.001). If women with haemoglobin >12 g/dL and <13 g/dL6,7 are included, the overall prevalence of suboptimal preoperative haemoglobin is approximately 20%. Women have lower circulating blood volume but similar perioperative blood loss and transfusion triggers; thus those presenting with haemoglobin >12 g/dL and <13 g/dL are likely to significantly contribute to transfusion rates in non-anaemic patients. If the data were re-analysed for patients presenting with optimal versus suboptimal preoperative haemoglobin concentrations, the differences in transfusion rates would be even greater (approximately 5 vs 40%, respectively)11.

This study also showed that preoperative anaemia increased median LOS by 1 day (2 vs 3; p<0.001) and the risk for LOS >5 days by 3-fold10. LOS is frequently overlooked despite several studies clearly identifying an association between ABT and increased LOS11,12. Reduction in LOS is difficult to evaluate because there are often no rigid criteria for hospital discharge. However, this is not the case for patients undergoing THA or TKA in a standardised, short-stay, multimodal, fast-track regimen13. The authors also found that preoperative anaemia increased 90 day readmission rates10. Although strongly influenced by ABT, extended LOS and increased rates of hospital readmission are indicators of postoperative morbidity in anaemic patients, and have implications for both the patients’ well-being and costs to the healthcare system.

The above-mentioned factors should be considered when implementing a patient blood management programme. Preoperative stimulation of erythropoiesis is a fundamental pillar for such programmes. As the most common sources of anaemia among orthopaedic surgical populations are related to iron deficiency and chronic diseases, the majority of anaemic patients may benefit from intravenous iron administration, with or without recombinant human erythropoietin14,15. Importantly, preoperative stimulation of erythropoiesis should not be denied to non-anaemic women with suboptimal haemoglobin level, as it may reduce exposure to ABT and its associated risks.