The contribution that blood transfusion has made to modern medicine can not be overstated. The procedure has saved many lives since the early nineteenth century, when the enabling discovery of distinct blood types was first made. However, blood and blood products are not only expensive, but they are also associated with significant patient risk. Avoidance of blood transfusion of donor blood is now recommended, whenever possible, therefore. Worthing Hospital’s, consultant anaesthetist and chair of its transfusion committee with a longstanding interest in the field of blood management, Dr Howard Wakeling, pointed out that donor blood is also scarce. He explained that the national blood transfusion website shows that for the more popular varieties of blood only three days worth of supplies are held nationally. “It would not take much of a drop in the donor pool for this to fall considerably, putting our blood stocks in a very precarious situation. Many hospitals now have an O-/O+ policy based on gender and age and O+ blood is often given to males, or women well above child-bearing age, instead of O- because the stocks as so poor,” he commented, adding: “Recently, with the threat of a flu epidemic, we have had to take a close look at the way we manage blood at the Trust and have been developing an action plan.” He explained that the Trust’s strategy to minimise donor blood transfusion has also been driven by a commitment to reduce the risk of potential complications. “A transfusion reaction can occur due to an error anywhere in the chain – from the taking of the blood, through to the laboratory, to actually administering the blood. There is also a risk of transmitting infection, including vCJD, and we know that immune modulation occurs when patients receive donor blood,” Dr Wakeling continued. He added that donor blood transfusion also increases the risk of SSIs in patients having surgery. Furthermore, it is known that cancer survival is adversely affected, while patients who receive donor blood also experience longer hospital stays. There are a variety of approaches, that can be taken pre-operatively, which can help minimise the need for blood donor transfusion, including:
• Iron therapy, Erythropoietin.
• Pre-donation.
• Stop anticoagulants.
• Stop anti-platelet drugs.
• Stop non-selective COX-2 NSAIDs.
However, Dr Wakeling highlighted the fact that, for iron therapy, anaemic patients need to be identified early on for this to prove a viable strategy. In addition, there are logistical issues associated with getting patients in several weeks before surgery, to provide a supply of their own blood for pre-donation. Intra-operatively, some of the ways that donor blood transfusion can be avoided include:
• Maintaining normothermia.
• Haemodilution.
• Hypotension.
• Antifibrinolytics.
• Blood/cell salvage.
“Post-operatively, we can also use a wound drain re-transfusion system, while the use of sensible transfusion triggers is obviously very important,” Dr Wakeling continued. He explained that the hospital had been using blood salvage as a key part of its overall blood management strategy to reduce the need for donor transfusion.
The Worthing experience
Worthing Hospital had previously been using Dideco Electa cell salvage across both of its sites. The system had provided excellent service for revision hips, vascular cases, major cancer surgery and difficult cases of lower segment Caesarean section, but, in May 2009, the hospital decided to review its approach and ensure a culture change in the way blood was managed. “We found the original system rather cumbersome and it requires someone who knows exactly what they are doing. However, it is ideal for the really big blood losses or situations where the blood needs to be washed,” commented Dr Wakeling. “Nevertheless, it did not provide us with the whole solution, so we decided to look at the Sangvia system. “This is a disposable, relatively inexpensive system and is capable of re-transfusing up to 1,500 mL of whole blood at a cost of less than £100 per patient. “It is very simple and quick to set up – you just connect the components and secure the device at table height, then run in the citrate. Once you have collected a reasonable quantity and you want to drain it, you simply flick a switch at the top, allowing the fluid to drain into the blood bag,” he explained. At the moment the manufacturer, Astra Tech, recommends 1,500 mL as the safe re-transfusion limit. However, it is expected that with time this limit will gradually rise as larger volumes are shown to be safe. Dr Wakeling pointed out that, with this system, there is a need for a clean collection area, as the blood is not washed, and users need to avoid taking up too much saline irrigation as this will dilute the blood collected. “Some surgeons have suggested that the suction is weaker,” he continued, “but the two surgeons who are the main users of this device in Worthing argue that that having slightly less suction is far less of a problem than the patients receiving donor blood.”
Case study
Illustrating the use of the system at the hospital, Dr Wakeling cited the case of a 64-year-old patient undergoing revision surgery, who was normotensive, on no medications, with a pre-op haemoglobin of 15. Outlining the procedure, he commented: “The patient’s second operation was a relatively lengthy one lasting 150 minutes. His heart rate remained stable throughout; his blood pressure was pretty good and stroke volumes and cardiac indexes were very good throughout the operation. Initially, I optimised his stroke volume using 1,000 mL of Voluven. As the operation progressed, we collected the first 1,500 mL of lost blood using the Sangvia system which was returned to the patient in 400 mL aliquots. “He went on to lose a further 1,500 mL and this was discarded, as we would have exceeded the current recommended limit. Fluid was then replaced with Voluven, guided by oesophageal Doppler ultrasound. “In recovery, the patient’s haemacue was 9.2 g/dl and, post-operatively, he required just one 500 mL bolus of Gelofusine for slightly low blood pressure. Other than this, he was completely stable and the following morning his haemoglobin was 9.4. He had no ileus; he mobilised well and went home on day five. “In his previous operation, he had started off with a haemoglobin of 15.5, but, during the operation, he showed a haemacue reading of 9.5 g/dl and, as there was a long time still to go, he required a two-unit transfusion at this point. His post-op haemoglobin was 10.3. Despite the fact that there were similar blood losses, for both operations, the second (and arguably bigger) operation did not require donor blood transfusion.” This blood management approach is now integrated into the culture at Worthing and the aim is now to provide training to support roll out in other areas. Dr Wakeling explained that he saw the potential for the system to be used on more trauma patients, while consideration could also be given for increased use during post-op blood salvage. In conclusion, he commented: “The ability to use these systems for salvage, in cases where there is a need for less than 1,500 mL of blood, has enabled us to free up our larger cell salvage machines for patients who have the bigger losses or blood that needs washing.”
The Dorset experience
Dr Duncan Farquhar-Thomson, consultant anaesthetist at Dorset County Hospital Foundation Trust, has been part of an enduring campaign to stop the unnecessary use of donor blood and has focused his efforts in the area of hip surgery. Studies have shown there is widespread variation in the use of red blood cells for total hip replacement surgery. Moreover, despite the availability of national guidelines, several audits have shown that a significant amount (10% to 15%) of all red cell transfusions could have been avoided in the perioperative period. “The results of a national comparative hip audit, published in 2007, showed that 25% of patients undergoing primary hip arthroplasty receive donor blood transfusion. Ten per cent of all donor blood is used for orthopedic surgery which is an enormous amount,” he explained. “Anaemic patients also continue to present for surgery and 15% are still operated on. Patients are also being over transfused,” he warned. Dr Farquhar-Thomson highlighted the results of a local audit, involving 40 patients, which showed similar results to the national audit: • 25% of patients were transfused. • The mean transfusion volume was 2.4 units. • 75% of anaemic patients with Hb <12 were transfused. • 71% of patients that were transfused had post tx Hb >10. A study was conducted to establish whether transfusion rates, length of hospital stay and complication rates could be reduced by using the Sangvia system. “Our conclusion was that the strongest predictor for the need for transfusion in primary hip arthroplasty was preoperative anaemia and this is a real problem for us, in Dorchester, because our patients are coming in for pre- operative screening about five days before surgery. It is only at that point that we discover the anaemia,” he commented. “No patients that used Sangvia intra- and post-operatively required donor blood transfusion and the average volume of blood re-infused in those patients was 550 mL – a significant quantity. Overall, we managed to reduce our transfusion rates and, possibly reduced hospital stay, but there have been significant cost savings too,” he added, concluding: “Our aim now is to reduce our transfusion rate down to zero in primary hip surgery, as well as to correct all pre-op anaemias.”
• The Astra Tech satellite symposium, “Current thinking in blood management”, was held at the Association of Anaesthetists of Great Britain and Ireland’s annual WSM conference, Westminster, London.