The Role Of Post-operative Autologous Blood Transfusion In Protecting Future Blood Stocks

Donor blood is in short supply. Despite awareness drives from the National Blood Service aimed at encouraging more people to donate, the risk of a shortage continues to loom. Under normal circumstances, where supply meets demand, enough blood is available to satisfy requirements and it is fair to say that normal circumstances, for the most part, tend to prevail. However, the question that raises concerns is what happens when the normal becomes abnormal and, most importantly, how will allocation of blood be prioritised in the event of a shortage?

The Integrated Blood Shortage Plan was implemented in 2005 by the Chief Medical Officer's Blood Transfusion Committee with a view to answering this question by developing a national framework for the management of both acute and chronic blood shortages. This has strong links to a previous publication circulated by the Department of Heath in 2002 called Better Blood Transfusion 2 (BBT2). The purpose of BBT2 was to ensure that there were sufficient mechanisms in hospital trusts to guarantee the most appropriate use of blood and to ensure that patients were provided with better information about blood transfusion. Key elements of both documents aim to reduce the unnecessary use of banked blood with the objective of avoiding a shortage, and also to provide a clear plan of action, including effective prioritisation of blood, should a shortage occur.

The implications, for current transfusion requirements, of an acute or chronic shortage could be quite different and resulting challenges may need to be managed differently. For instance, an acute shortage of blood caused by a flu epidemic, or similar situation, which temporarily prevents donors from attending donor sessions may be enough to require action. However, couple this with a greater demand for blood due to an unforeseen incident requiring immediate allocation and a more critical acute shortage may occur. Management of such an event could include immediate awareness campaigns encouraging people to donate and may also be donor driven with donors themselves volunteering additional blood in order to provide assistance. Situations such as this have occurred when the need for blood is a particularly public event, such as in the aftermath of 9/11 and the London bombings in July 2005.

Legislative Measures

Additionally, there is a risk of surgical cancellations being employed in order to help manage shortages. Indeed, in June 2005, hospitals in Ireland were called upon to cancel all elective surgery over a period of 4 days due to a shortage of blood. Legislative reasons were cited as one of the driving forces behind these cancellations and it is such reasons that could lead to the acute shortages of today becoming the chronic shortages of tomorrow. More recently (June 2007), it was identified that only 3 days stock of some blood groups were available in Scotland.

UK legislation set in 2004 prevents anyone who has received a blood transfusion since 1st Jan 1980 from donating blood due to the risk of transmission of vCJD. In Ireland, the legislation extended to anyone who had lived in the UK for a year or more between 1980 and 1996. In the UK, the legislation resulted in a reduction in the donor pool of around 55,000 donors. This has undoubtedly had a significant impact on the current and future availability of blood. On top of this, the much discussed implementation of a vCJD screening test has led to fears of more donors refusing to continue making donations due to concerns surrounding the potential socioeconomic effects of an individual knowing, and in some cases having to declare (for example for the purposes of life assurance) that they are a carrier. With these issues plus the fact that fewer younger people are donating, increasing the average age of donors, there are, unsurprisingly, continued concerns about the potential for chronic supply problems.

The key to success surely lies with avoidance of the necessity to manage such a shortage by focussing on preventative measures. In the face of such potential adversity, it becomes even more important to ensure compliance with BBT2 to ensure that banked blood is only being used when it is really needed and to implement methods that may help to reduce transfusion requirements in order to avoid surgical cancellations and, in the worst case, the need to prioritise blood allocation in emergencies. With Better Blood Transfusion 3 due for publication imminently, there is likely to be renewed interest and action in the blood transfusion arena and a continued drive towards further improvements.

Avoiding the unnecessary use of blood through post-operative ABT

So, how can the unnecessary use of blood be avoided? In the first instance, elective surgery can be targeted because the ability to be able to plan carefully can lead to an understanding of the likely volume of blood loss and allow for the use of methods to reduce banked blood use. Around 6% of blood transfusions in the UK are administered to patients undergoing elective hip and knee replacement surgery 1. With around 2 million units of red cells being issued per year in the UK 2 the total requirement for hip and knee replacements is around 120,000 units. With donors eligible to donate approximately every 16 weeks, this represents an annual donor capacity of around 40,000 donors and could, therefore, provide a valuable resource for transfusion in areas where alternative measures are not indicated.

One increasingly important method of reducing the need for transfusion is post-operative autologous blood transfusion (ABT). This is a simple method requiring the placement of a wound drain at the surgical site which is in turn connected to a collection device that provides a vacuum for suction of blood from the wound. The blood is then returned to the patient post-operatively through filtration. The filtration capability of the device is ultimately important as blood collected from orthopaedic surgery can contain undesirable materials such as bone and bone cement fragments, activated white cells, complement proteins and fat particles, the re-infusion of which could lead to clinical complications. Such devices have been in use in the UK for around 20 years and have an excellent track record for reducing the need for homologous transfusion.

Historically, the use of these devices has been focussed on total knee replacement (TKR) surgery – the use of a tourniquet rendering the vast majority of the blood loss post-operative. There have been many instances where a reduction in the transfusion requirements has been demonstrated 3,4,5 and, on top of avoiding additional risks 6,7, has contributed to other benefits such as reduced patient length of hospital stay 3, reduction in infective episodes 3 and a reduction in the risk of transfusion transmitted infections such as HIV, Hepatitis and vCJD 7. Indeed, a number of studies recommend the routine use of ABT when performing TKR 4,8,9.

With the pressure always on to further reduce transfusion requirement, the use of post-operative ABT systems has also extended to total hip arthroplasty (THA) with total hip replacement (THR) being the most common surgical indication for transfusion accounting for 4.6% of all blood used 1.

Although perhaps not used as widely as with TKR, post-operative ABT has mainly been used on revision hips as the expected blood loss post-operatively warrants caution and transfusion rates can be quite high. However, progress is also being made with the use of these devices in primary hips and significant reductions in the requirement for banked blood have been shown 10.

In order to ensure that the most appropriate transfusion alternatives are available, and particularly if using post-operative ABT, it is advisable to reduce the intra-operative blood loss as far as possible. There are various methods for the reduction of intra-operative blood loss that are currently employed in THA and successful implementation of these can result in an increase in the proportion of total blood loss that occurs post-operatively. This means that any transfusion requirement is likely to be more closely related to post-operative blood loss than blood lost intra-operatively making post-operative ABT the most appropriate autologous solution.

The following case studies demonstrate how appropriate patient management can help to reduce blood transfusion requirements in primary THA.

Case 1: Queen's Medical Centre (QMC), Nottingham
Malcolm Chambers (Transfusion Practitioner / Autotransfusion course co-ordinator, QMC) presented the findings of a transfusion audit at the AfPP Congress in 2006. The audit was aimed at determining the best process of care for patients undergoing THR in order to minimise post-operative transfusion requirement. QMC adopted a 3 stage approach considering blood conservation activities in the pre-operative, intra-operative and post-operative settings. These included pre-assessment of patients in outpatient clinics in order to maximise haemoglobin levels prior to surgery. Patients not meeting the minimum criteria were referred back to their GP in order to receive the necessary treatment for anaemia. Intra-operatively, cell salvage was employed along with, if indicated, the use of antifibrinolytic drugs. This was followed by the use of post-operative ABT. The process of patient care was designed such that it met the requirements of the individual patient based on pre-assessed clinical indicators.

The move to this approach came about as a result of the transfusion audit which showed that 43.5% of Primary Total Hip Replacements (PTHR) patients were being transfused with 35.3% receiving two or more units. 10.5% of patients were transfused intra-operatively with 100% transfused post-operatively. Of those transfused post-operatively, 36.1% had lost 400-600ml of blood after completion of surgery. Since full implementation, the blood ordering schedule has changed from a 4 unit cross match in PTHR (6 unit cross match for revisions) to group and save only in PTHR and a 2 unit cross match for revisions due to confidence in the ability of post-operative ABT to reduce homologous transfusion requirements.

Case 2: St Mary's Nuffield, Bristol
Dr David Coates (Consultant Anaesthetist, St Mary's Nuffield) presented information regarding the use of post-operative ABT use in THA at the AfPP Congress in 2005. The findings of an audit showed transfusion rates of 40% with routine cross-matching for every patient. The use of hypotensive anaesthesia in order to reduce intra-operative blood loss has meant that post-operative ABT has become an important part of the transfusion reduction programme and enabled St Mary's to come away from the more complex intra-operative machines 11. Since implementing a protocol including post-operative ABT for use in THA, transfusion rates have dropped to 5% and routine cross-matching no longer takes place. Cross-matching adds expense to the transfusion process and will now only take place if the patient arrives for surgery with a clinically low Hb level, or if the routine group and save identifies unusual antibody presence.

More recently, Dr Coates has noted that, although transfusion requirement has dropped at St Mary's Nuffield in Bristol, there are still many locations throughout the UK where potentially avoidable transfusions are still taking place and where, therefore, significant improvements in transfusion practice could be achieved with the right protocols in place.

Future considerations affecting the UK blood supply

The advantage of focussing on elective orthopaedic procedures is twofold. Firstly, 6% of all blood used is accounted for by hip and knee replacements and the nature of elective surgery means that careful planning can help reduce the requirement for banked blood. There have been many other reasons to consider the need to plan including donor shortages and inherent risks associated with the use of donor blood and, as time goes on, further implications continue to arise.

The inclusion of prion filtration in the routine processing of donated blood, aimed at reducing the risk of transmission of vCJD, is imminent, with fears of additional cost burden on hospitals performing transfusions. The vCJD screening test which is largely anticipated, but as yet with no clear timetable for implementation, has led to fears that the donor pool could reduce by up to 50% due to paranoia over potential social implications for known carriers. Indeed, current donors struck from the register due to increased risk may have previous transfusions traced back through the transfusion history in order to identify recipients who may, therefore, also be at risk. This method of managing risk and attempting to cut vCJD off at the source could have the knock on effect of removal of further potential donors from the donor pool.

With these changes in the logistics of blood donation and the consideration of potentially adverse clinical implications, a counter change is required in transfusion practice to ensure that the availability of blood for patients who have a genuine and unavoidable requirement for blood is unchanged. If the blood required cannot be made available through donation, then it must be made available through appropriate use programmes and alternative methods.

Better Blood Transfusion 2 has provided a platform for significant improvements in blood transfusion practice and, undoubtedly, there has been a reduction in the inappropriate use of blood. Indeed, in 2005-6, there was a 4.4% reduction in red cells issued over the previous year 2 providing a good indicator that appropriate use programmes are working. Better Blood Transfusion 3 is due for publication this year and will undoubtedly maintain emphasis on the need to reduce inappropriate blood use and should build on the momentum gained through previous publications. It is, however, ultimately down to actions in the clinical arena to ensure successful implementation of protocols in line with requirements. So, by understanding current usage and through the use of resources empowered to focus on blood transfusion practice, further improvements are possible. And let's not forget that success stories do exist and significant improvements have been made so sharing of knowledge and experience could result in rapid action. A symptomatic blood shortage looms closer and the quicker we act, the more likely we are to avoid what is often billed as “the inevitable”.


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