ABT In Clinical Practice

Blood transfusion (also referred to as banked, allogenic or homologous transfusion) is a powerful accessory to the practice of modern medicine. At one time it was an unquestioned part of patient care however its use is now being re-evaluated because of growing concerns for safety and shortages and costs.¹ Since the AIDS epidemic in the 1980's, followed by Hepatitis C, interest in alternative sources to allogenic blood is growing.

Cell salvage, also known as autologous blood transfusion is designed to reduce the need for banked blood. It involves the collection of the patient's own blood from the surgical sites which can then be transfused back into the same person after surgery as required. It is an endorsed blood conservation strategy which is now being practised in many elective surgical procedures.

The most recent stimulus for looking at alternatives to allogenic blood is the evidence that allogenic transfusions are associated with increased risk of myocardial infarction, heart failure, stroke, multiorgan failure and death.

Another important reason would be the growing demand of blood with a declining population of qualifying willing donors. The most recent concern is that vCJD could be transmitted by blood transfusion.² This has resulted in a more stringent procedure of donor selection and removal from the donor pool of those who may have been exposed to vCJD. The possibility of prion screening for vCJD in the future would result in the elimination of a sizable population of donors from the volunteer donor pool, which would result in blood becoming even scarcer.

The blood supplies in the UK are considered one of the safest in the world however efficient screening of blood has resulted in mounting costs with a unit of blood now costing around £150. In the future the costs are expected to escalate even more:

The benefits of autologous blood are numerous and well documented. The patients are getting their own blood back, it minimizes their concerns for safety, and reduces the chances of any bedside errors. Blood can be grouped and saved instead of being routinely cross matched unless there is a specific indication for some to be immediately available. There is also some preliminary evidence that it leads to a decreased length of hospital stay, has beneficial immunomodulatory effect and may reduce postoperative infections.⁴

CellTrans™ System Components

Orthopaedic surgery accounts for 11% of all the allogenic blood transfusions. Autologous blood transfusion is well established in Total Knee Arthroplasty (TKA) and is recommended by the British Orthopaedic association. The recently published Cochrane systematic also showed that cell salvage reduces the need for transfusions of donated blood. The authors concluded that “there appears to be sufficient evidence to support the use of cell salvage in orthopaedic surgery. Cell salvage does not appear to cause any adverse clinical outcomes.”⁵

There is however room for growth in the use of ABT systems in primary hip replacements. The National Comparative audit report of 2006/2007 states that out of the patients undergoing primary elective total hip replacement, 25% needed transfusions. Two thirds of these patients received two units of blood while 27% received three or more units.⁶

CellTrans™ System in operation at the bedside

Autologous blood transfusion drainage systems may be used in elective and/or emergency Orthopaedic procedures but unwashed re-infusion systems are best used when the expected blood loss is between 500 and 1000ml. The requirements are however different for knee arthroplasty and hip arthroplasty. In TKA the intra operative loss of blood is small because of the application of a tourniquet. Drains are put in as usual after the surgery and connected to a collection device. This operates under a low vacuum of less than 100 mm Hg. After the release of tourniquet there is a more immediate loss of blood, this blood is collected and re infused.

In hip arthroplasty there can be a late increase in blood loss as the effect of local anaesthesia wanes and the patient starts to move more freely in bed. If a single bag system is employed, the benefits of collecting and reinfusing the late loss may be missed.⁷ A system that collects over a period of 12 hours postoperatively would appear to be a reasonable choice suitable for both knees and hips. Once the blood has been collected and reinfused, the system should be able to collect as a traditional wound drain.

The CellTrans™ system (by Summit Medical Ltd) has been shown to be valuable in both knee and hip replacements. It differs from other devices in having two dedicated ports and bags for blood collection. This enables a closed circuit to be maintained for blood collection, thereby minimizing the risk of infection. A total of 1200ml can be collected in two 600 ml bags.

The first transfusion is started within 6 hours of collection and the second bag can be used to collect blood for a further 6 hours, as indicated in the AABB guidelines.⁸

The other added benefit of the CellTrans™ is the Pall LipiguardR filter which reduces the fat globules, microaggregates, activated leucocytes as well as complement before reinfusion. The Pall LipiguardR filter is supplied as part of the CellTrans™ device.

In an audit from North Middlesex hospital, approximately 30 units of red cells were saved over the 22 patients who received the CellTran™ system allowing the use of this precious and scarce resource on other patients. This identified a significant saving of £2400 based on the cost of one unit of blood being £120.

Another audit done at Nuffield hospital, St Mary's Bristol compared CellTrans™ versus conventional low vacuum drains in patients undergoing primary hip arthroplasty. The use of CellTran™ allowed the rate of donor transfusion to reduce from 40% to 6%.⁷ Other data has shown that length of stay in the hospital was significantly reduced compared with the suction drain group.⁹

If postoperative ABT is routinely used in clinical practice for knee arthroplasty as recommended by the British Orthopaedic Association, it would generate a multi million pound saving to the NHS. If this use is extended to patients undergoing primary hip arthroplasty, and the use of allogenic transfusion brought down from its present 40% to about 10%, this would achieve an additional saving of an equivalent amount.⁷ In addition to cost saving it would meet the objective of using allogenic blood more appropriately and saving this resource for patients in whom ABT cannot be used.

The BBT guidelines stress the need for providing training and information to the clinicians undertaking transfusion. The guidelines also stress the importance of the provision of timely written information about blood transfusion and its alternatives to patients at risk of needing a blood transfusion.¹

References

1. Better Blood Transfusion Safe and Appropriate use of Blood (HSC 2007/001)
2. Llewelyn et al. Possible transmission of variant Creutzfeldt-Jakob disease by blood transfusion. The Lancet 2004;363:417-421.
3. The Serious Hazards of Transfusion (SHOT) Annual Report 2006. www.shotuk.org
4. Gharehbaghian et al. Effect of autologous salvaged blood on postoperative natural killer cells precursor frequency. The Lancet. 2004;363:1025-1030.
5. Carless PA, Henry DA, Moxey AJ, O'Connell DL, Brown T, Fergusson DA. Cell salvage for minimising perioperative allogeneic blood transfusion. Cochrane Database of Systematic Reviews 2006, Issue 4. Art. No.: CD001888. DOI: 10.1002/14651858.CD001888.pub2.
6. National Comparative Audit of Blood Transfusion. NHS Blood and Transplant Annual Report 2006/07
7. Coates D. From Presentation at “Procuring for Healthcare 2006: Investing in innovation. Belfry, West Midlands.UK
8. AABB guidelines and standards for blood banks and transfusion services. Guidelines for blood recovery and reinfusion in surgery and trauma ISBN 978-3-8055-8510-1
9. NHS Economic Evaluation Database. Jones at al. Postoperative autologous blood salvage drains: are they useful in primary uncemented hip and knee arthroplasty? A prospective study of 186 cases. Acta Orthopaedica Belgica. 2004:70(5);466-473.

For more information contact:
Summit Medical Ltd
Tel: +44 (0)1541 821311
Email: info@summit-medical.co.uk
Web: www.summit-medical.co.uk

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