Blood transfusion

Why the committee made the recommendations

Although the committee recognised that the evidence did not cover all surgical specialties, they agreed it showed that using tranexamic acid during surgery to prevent bleeding is safe at the typical doses stated in the recommendations, and is generally clinically effective and cost effective. As such, they made recommendations for surgery in general rather than making specific recommendations for different types of surgery.

Evidence showed that tranexamic acid can reduce length of hospital stay, as well as the need for blood transfusion, for people having surgery where minor blood loss is anticipated. The committee agreed that the benefit of reducing length of stay may be less for some types of surgery not covered by the evidence, for example, day case surgery.

Separate evidence showed that tranexamic acid was safe for most people, reducing all-cause mortality and further operations. There was an increased risk of thromboembolic events in less than 0.1% of people.

Based on their clinical experience, the committee identified the following additional potential clinical benefits of tranexamic acid:

While length of stay was found not to have an impact on quality of life in the economic model, it did reduce hospital costs and meant tranexamic acid was found to be cost effective. When length of stay was excluded from the economic model, tranexamic acid was only cost effective for types of surgery where the probability of a blood transfusion was 2% or more. The committee was confident that tranexamic acid was cost effective for most types of surgery in operating theatres because of other potential benefits not examined by the model. These included:

The committee agreed that tranexamic acid should be offered to adults undergoing surgery that breaches the skin or mucous membranes when there is any risk of bleeding provided it takes place in an operating theatre. This was to exclude quick, low-risk procedures in the community where tranexamic acid does not offer sufficient benefits. By only selecting surgery taking place in an operating theatre, the committee was reassured that staff who were trained to give medicines intravenously would be available, if needed. The requirement for the surgery to breach the skin or mucous membranes was stated since bleeding always occurs here, which is not the case for cornea surgery and some invasive diagnostic procedures such as hysteroscopy. Other types of surgery that cause bleeding were excluded because the amount of bleeding would be expected to be much lower. The committee agreed that the benefits of tranexamic acid will outweigh the risks for most people having surgery. However, they recognised this will not always be the case, for example, if the person has known active thromboembolic disease or ongoing intravascular clotting.

A separate recommendation was made for adults undergoing surgery outside of operating theatres. This retains part of the 2015 recommendation to offer tranexamic acid to adults undergoing surgery who are expected to have blood loss greater than 500 ml.

There were only a small number of studies on the effectiveness of tranexamic acid for children having surgery where minor blood loss was anticipated, and only 1 study on its safety for this population. The results of this evidence were inconclusive. The committee acknowledged that blood loss can be more significant in children than adults because children have a smaller total blood volume. They also discussed that the margin of error regarding dosing decisions for children may be more critical. Given all this, the committee agreed that weighing up the benefits of tranexamic acid against the risks is especially important for children. They also agreed that tranexamic acid could be an option for some children undergoing surgery in an operating theatre that breaches the skin or mucous membranes.

In line with the 2015 guideline, the committee agreed that tranexamic acid should be considered for children having surgery where more than 10% of blood loss is expected. Evidence for adults showed clearer benefits of giving tranexamic acid when blood loss was higher and the committee agreed that this could be applied to children. Because children having a lower total blood volume than adults, a value of 10% is used instead of an absolute volume.

There were no studies that only looked at young people. Three studies had a small number of young people. These only reported total blood loss and adverse events, rather than length of hospital stay and the need for blood transfusion. Because of the lack of evidence on young people and in line with the 2015 guideline, the committee decided not to make recommendations for young people and agreed that the recommendations for adults would generally apply to them with healthcare professionals expected to use their clinical judgement about this.

The committee made recommendations about doses of tranexamic acid using information from the trials, the summary of product characteristics and recommendations made by other groups.

They recognised that while an additional dose of tranexamic acid would sometimes be needed, a single dose is usually sufficient because of the length of most operations and level of blood loss. The committee agreed that the decision to give an additional dose should be based on the balance of benefits and harms of doing so. In particular, they discussed that people with renal impairment may not be suitable for an additional dose or may require a reduced additional dose.

Tranexamic acid can be fatal if administered by the wrong route. The committee agreed that it was important to flag the need for safety measures to prevent this from happening.

To inform future recommendations, the committee agreed a recommendation for research on the effectiveness of tranexamic acid in children and young people, acknowledging the current study into its safety for under 18s.

There was no direct evidence on the clinical effectiveness of tranexamic acid for vascular surgery with minimal risk of bleeding but the committee agreed that the results from other evidence looking at cost effectiveness could be applied to this population. Although vascular surgery was covered by 1 study that looked at the safety of tranexamic acid, the results were not reported by surgical specialty and so could not be analysed separately. Uptake of the previous recommendation on using tranexamic acid for surgery where blood loss is greater than 500 ml was lower for vascular surgery. The committee agreed that further research was required to inform future recommendations on vascular surgery and so made a recommendation for research on the effectiveness of tranexamic acid for specific vascular surgery procedures.

How the recommendations might affect practice

In 2015 NICE recommended offering tranexamic acid to adults having surgery where expected blood loss was more than 500 ml. The new recommendations extend use of tranexamic acid to any level of expected blood loss but only for adults having surgery in operating theatres. This is likely to increase the use of tranexamic acid but should not have an impact on staffing requirements since operating theatres should already have staff available to administer the medicine.

For children, the recommendations also extend the use of tranexamic acid from only where expected blood loss is more than 10% to cover any level of expected blood loss in operating theatres. Again, although this is likely to increase the use of tranexamic acid, it should not have staffing implications.

Overall, it is expected that the recommendations will reduce costs because fewer people will have blood transfusions and the average length of stay in hospital after surgery will be reduced.

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