A Randomised Controlled Trial and Economic Evaluation of Intra-Operative Cell Salvage during Caesarean Section in Women at Risk of Haemorrhage: The SALVO Trial (cell SALVage in Obstetrics)

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Abstract

Background: Caesarean section is associated with blood loss and maternal morbidity. Excessive blood loss requires transfusion of donor (allogeneic) blood, a finite resource. Cell salvage returns blood lost during surgery to the mother. It may avoid the need for donor blood transfusion, but reliable evidence of its effects is lacking.
Objectives: To determine if routine use of cell salvage during caesarean section, in mothers at risk of haemorrhage, reduces the rates of blood transfusion and postpartum maternal morbidity, and is cost-effective, in comparison to standard practice without routine salvage use.
Design: Individually randomised controlled, multicentre trial with cost-effectiveness analysis. Treatment was not blinded.
Setting: 26 UK obstetric units.
Participants: Of 3054 women recruited between June 2013 and April 2016, we randomly assigned 3028 women at risk of haemorrhage to cell salvage or routine care. Randomisation was stratified, using random permuted blocks of variable sizes. Of these, 1672 had emergency and 1356 elective caesareans. We excluded women for whom cell salvage or donor blood transfusion was contraindicated.
Interventions: Cell salvage (intervention) versus routine care without salvage (control). In the intervention group, salvage was set up in 95.6% of the women and, of these, 50.8% had salvaged blood returned. In the control group, 3.9% had salvage deployed.
Main outcome measures: Primary: donor blood transfusion. Secondary: units of donor blood transfused; time to mobilisation; length of hospitalisation; mean fall in haemoglobin; fetomaternal haemorrhage measured by Kleihauer test; maternal fatigue. Analyses were adjusted for stratification factors and other factors believed to be prognostic a priori. Cost-effectiveness outcomes: costs of resources and service provision taking the UK National Health Service perspective.
Results: We analysed 1498 and 1492 participants in the intervention and control groups, respectively. Overall, the transfusion rate was 2.5% in the intervention group versus 3.5% in control (adjusted odds ratio [OR] 0.65, 95% confidence interval [CI] 0.42 to 1.01, p=0.056). In a planned subgroup analysis, the transfusion rate was 3.0% in intervention versus 4.6% in control among emergency caesareans (adjusted OR 0.58, 95% CI 0.34 to 0.99), whereas it was 1.8% versus 2.2% among elective caesareans (adjusted OR 0.83, 95% CI 0.38 to 1.83) (interaction p=0.46, suggesting that the difference in effect between subgroups was not statistically significant). Secondary outcomes did not differ between groups, except fetomaternal haemorrhage was higher under salvage in Rhesus D-negative women with D-positive babies (25.6% vs. 10.5% adjusted OR 5.63, 95% CI 1.43 to 22.14, p=0.013). No case of amniotic fluid embolism was observed. The additional cost of routine cell salvage during caesarean was estimated, on average, at £8,110 per donor blood transfusion avoided.
Limitations: We are unable to comment on long-term antibody sensitisation effects.
Conclusions: The modest evidence for an effect of routine use of cell salvage during caesarean section on rates of donor blood transfusion was associated with increased fetomaternal haemorrhage, which emphasises the need for adherence to guidance on anti-D prophylaxis. Based on the findings of this trial, cell salvage is unlikely to be considered cost-effective.
Future work: Research into risk of alloimmunisation among women exposed to cell salvage is needed.
Study Registration: ISRCTN66118656.
Funding Details: This project was funded by the NIHR Health Technology Assessment programme, project reference number 10/57/32.

Details

Original languageEnglish
JournalHealth Technology Assessment
Publication statusPublished - 3 Apr 2016

Keywords

  • Cell Salvage, Caesarean Section, Obstetrics