Reducing blood transfusion in obstetrics

Fears regarding the safety of blood products, along with concerns about its rising costs (from approximately £40 in 1998 to nearly £140 in 2006) and limited supply, have prompted the Department of Health to initiate the Health Service Circulars ‘Better Blood Transfusion’, which outline the need for a number of blood conservation strategies. The subject of blood conservation is especially important in obstetrics (which account for 3% of all blood transfused in the UK), where haemorrhage can occur rapidly and clinical estimations of blood loss are notoriously inaccurate (Bose et al. 2006; Yoong et al. 2010).

While it can be undoubtedly life-saving, blood transfusion is not without hazard: there have been four deaths in the UK attributable to blood transfusion in 2006 alone and at least four cases of Creutzfelt–Jakob disease have been reported as of 2007 (Allam et al. 2008). In 2002, 92% of pregnant women in a questionnaire-based study from the West Midlands (Khadra et al. 2002) declared that they would accept blood transfusion, while in the multiethnic borough of Haringey, our recent survey of 130 expectant mothers revealed that 98.5% would do the same; moreover, non-English speakers were more likely to erroneously believe that allogeneic blood was ‘totally safe’ (57.1% vs 38.8%, p < 0.005) (Ridout and Yoong 2009).

The group of individuals for whom blood conservation strategies were initially developed, were the Jehovah's Witnesses (JWs), who base their refusal of blood on the literal interpretation of certain biblical verses. Bizarrely, increasing public demand in the USA, Canada and Europe for alternatives to blood has led to some patients falsely presenting themselves as JWs in order to avoid transfusion (Bragg 1997). Well-accepted strategies in women who decline blood transfusion include senior staff involvement, optimisation of haemoglobin, intraoperative cell salvage, surgical techniques such as compression sutures and balloon uterine tamponade as well as early recourse to hysterectomy in the event of massive obstetric haemorrhage (RCOG 2008).

In brief, perioperative red cell conservation techniques comprise:

1. Intraoperative cell salvage (ICS): Red blood cell salvage involves retrieval of the patient's blood shed during operative or vaginal delivery. The salvaged blood may be washed and/or filtered prior to re-infusion. In JW patients, the system is set-up as a continuous ‘loop’ which is pre-primed and run without disconnection until the end of the procedure. The main theoretical safety concerns are amniotic fluid embolism and fetomaternal isoimmunisation in future pregnancies. To minimise problems, a leucocyte depletion filter is recommended during reinfusion. And appropriate assessment to ensure the correct dose of anti-D immunoglobulin is administered postpartum to all RhD-negative women where intraoperative salvage is used. A review article (Allam et al. 2008), which included 400 obstetric cases compiled from case reports, a retrospective case series (n = 64), a historic cohort study (n = 139) as well as a prospective controlled trial (n = 34 in the cell salvage arm) suggested that there were no serious maternal complications that could be directly attributable to its use. Thus, several bodies, including the Confidential Enquiry into Maternal and Child Health, the American College of Obstetricians and Gynecologists, the Obstetric Anaesthetists' Association/Association of Anaesthetists of Great Britain and Ireland and the National Institute for Health and Clinical Excellence have endorsed the use of cell salvage in obstetric patients, even in women who are willing to accept allogeneic blood.

2. Acute normovolaemic haemodilution (ANH): This technique involves the removal of whole blood from the woman immediately preoperatively, while simultaneously infusing colloid and/or crystalloids. This maintains the circulatory volume but reduces the haematocrit, thus resulting in a smaller red cell mass loss during surgery. Unlike ICS, this product contains viable platelets and clotting factors. However, there is some concern over whether ANH in pregnancy would precipitate cardiac failure or cause placental insufficiency and this technique is probably not adequate in massive obstetric haemorrhage. A meta-analysis of 42 trials (Segal et al. 2004) showed that the quality of published literature was insufficient to recommend a firm conclusion on efficacy or safety of ANH, particularly in an obstetric setting.

3. Preoperative autologous donation: where the patient donates 1 or 2 units of blood, 1 or 2 months prior to delivery now has no role in emergency obstetric haemorrhage. Due to legal requirements the majority of hospitals no longer offer this service but it may have a limited use in women who are at a high risk of bleeding and in whom there are exceptional cross-matching difficulties.

4. Postoperative salvage: where the patient's blood that is normally collected into postoperative drains and then discarded, is collected into a sterile collection bag, filtered and reinfused. This type of salvage has been used as a conservation strategy to good effect in orthopaedic (replacement knee surgery) but has limited value in obstetrics.

The cost of disposables for ICS varies between manufacturers but generally the system is cost-effective for cases where over 1 litre of patient's blood is salvaged with 200–300 ml being returned to the patient, i.e. the disposables cost approximately the same as 1 unit of donor blood.

An important ethical issue is whether the pregnant woman who declines blood actually receives better obstetric care: her care is led by senior obstetricians; she has intensive antenatal improvement of haematinics; her delivery is as bloodless as possible, and she has access to technology such as cell salvage, which is safer than allogenic blood transfusion.

We argue that we should be providing this optimal level of care as standard (as is currently practised by some hospitals in the USA, who are offering formal bloodless surgery programmes), as this would not only prove cost-effective and safe but also help preserve our dwindling stocks of donor blood.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.