The National Institute for Clinical Excellence is examining intraoperative blood cell salvage in obstetrics and will publish guidance on its safety and efficacy to the NHS in England, Wales and Scotland. The Institute's Interventional Procedures Advisory Committee has considered the available evidence and the views of Specialist Advisors, who are consultants with knowledge of the procedure. The Advisory Committee has made provisional recommendations about intraoperative blood cell salvage in obstetrics.

This document summarises the procedure and sets out the provisional recommendations made by the Advisory Committee. It has been prepared for public consultation. The Advisory Committee particularly welcomes:

• comments on the preliminary recommendations
• the identification of factual inaccuracies
• additional relevant evidence.

Note that this document is not the Institute's formal guidance on this procedure. The recommendations are provisional and may change after consultation.

The process that the Institute will follow after the consultation period ends is as follows:

• The Advisory Committee will meet again to consider the original evidence and its provisional recommendations in the light of the comments received during consultation.
• The Advisory Committee will then prepare draft guidance which will be the basis for the Institute's guidance on the use of the procedure in the NHS in England, Wales and Scotland.

For further details, see the Interventional Procedures Programme manual, which is available from the Institute's website (www.nice.org.uk/ipprogrammemanual).

Closing date for comments: 22 March 2005

Target date for publication of guidance: June 2005

Note that this document is not the Institute's guidance on this procedure. The recommendations are provisional and may change after consultation.

Intraoperative blood cell salvage is a well-established and efficacious technique for blood replacement in other areas of medicine, but there are theoretical safety concerns when it is used in obstetric practice. Data collection is therefore important and clinicians should report all complications to the Serious Hazards of Transfusion Scheme (www.shotuk.org).

When possible, patients should be fully informed of the potential complications, and use of the Institute's Information for the public is recommended.

Intraoperative blood cell salvage is commonly used in cardiac, orthopaedic and vascular surgery. However, cell salvage has not been routinely adopted for women with postpartum haemorrhage following Caesarean section because of specific concerns about amniotic fluid embolism and about haemolytic disease in future pregnancies as a result of re-infusing fetal red blood cells or amniotic fluid.

Postpartum haemorrhage is defined as a blood loss of more than 500 ml after vaginal delivery or more than 1000 ml after Caesarean delivery. Uncontrolled haemorrhage after childbirth is a major cause of pregnancy-related death. Use of intraoperative cell salvage may reduce the incidence of transfusion reactions and transfusion-related infection, compared with the use of standard (allogeneic) transfusion.

The standard options for transfusion are:

• standard transfusion from a donor
• transfusion with blood that has been taken from the patient before childbirth (pre-donation)
• transfusion of blood removed from the patient at the time of the operation with volume replacement using intravenous fluids (acute normovolaemic haemodilution).

Intraoperative blood cell salvage is the process whereby blood shed during an operation is collected, filtered and washed to produce autologous red blood cells for transfusion to the patient.

In the blood cell salvage arm of a controlled trial, the median volume of re-infused blood was between 250 and 543 ml per woman (n = 139). There was no significant difference in length of hospital stay, time on ventilatory support, intravascular coagulation, or infection morbidity between women who received salvaged blood and women in the control group, who received standard transfusions.

The Specialist Advisors noted that the efficacy of the procedure may depend on the nature and volume of the blood loss.

In the blood cell salvage arm of a controlled trial, there were no instances of acute respiratory distress or amniotic fluid embolism in 139 women. In the blood cell salvage arm of a comparative study of 54 women who had a Caesarean section, there were no reported complications from re-infusing salvaged blood. For more details, refer to the sources of evidence (see Appendix).

The Specialist Advisors noted that the theoretical safety concerns include infusion of fetal cells potentially causing haemolytic disease in future pregnancies, and infusion of amniotic fluid causing amniotic fluid embolism.

The following document, which summarises the evidence, was considered by the Interventional Procedures Advisory Committee when making its provisional recommendations.

Interventional procedure overview of intraoperative blood cell salvage in obstetrics, December 2004

Available from: www.nice.org.uk/ip040overview