Grand Rounds
CMECNE

Results of the SALVO Trial: Cell Salvage During Cesarean Section

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Learning Objectives and CME/Disclosure Information

BACKGROUND AND PURPOSE:

  • Cell salvage collects, processes, and returns the woman’s own blood lost during surgery
  • Cell salvage during non-obstetric surgery can prevent blood transfusion
  • Limited data is available for the benefit of this technique during cesarean section
  • There is a concern for amniotic fluid embolism and red cell isoimmunization with cell salvage
  • Khan et al. (PLoS Med., 2017) sought to confirm if cell salvage can reduce the need for transfusion

METHODS:

  • Pragmatic randomized controlled trial
  • SALVO trial (cell SALVage in Obstetrics), including 26 UK obstetric units
  • Women undergoing cesarean section at risk of hemorrhage were randomized to either
    • Cell salvage
    • Current standard of care without salvage use
  • Multivariable models was used for an intention-to-treat analysis
  • Primary outcome
    • Rates of donor blood transfusion
  • Secondary outcome
    • Fetomaternal hemorrhage ≥2 ml in RhD-negative women with RhD-positive babies

RESULTS:

  • 3,028 women were randomized, with 2,990 women included in the analysis
    • 1498 in intervention group / 1492 in control group
  • Intervention group
    • Cell salvage deployed in 95.6%
    • 50.8% had salvaged blood returned (mean volume of returned blood was 259.9 ml)
    • 3.9% of the control group had cell salvage
  • Blood transfusion rate
    • 3.5% in the control group
    • 2.5% in the intervention group
    • Adjusted odds ratio [OR] 0.65 (95% CI, 0.42 to 1.01, p = 0.056)
    • Adjusted risk difference -1.03 (95% CI, -2.13 to 0.06)
  • Planned subgroup analysis: Comparing transfusion rates in emergency vs elective cesarean
    • Emergency cesarean: Transfusion rate was 4.6% in controls vs 3.0% in the intervention group among emergency cesareans (adjusted OR 0.58, 95% CI 0.34 to 0.99)
    • Elective cesarean: Transfusion rate was 2.2% in controls vs 1.8% (adjusted OR 0.83, 95% CI 0.38 to 1.83)
  • Fetomaternal hemorrhage
    • 25.6% in the intervention group vs 10.5% in the control group
      • Adjusted OR 5.63 (95% CI, 1.43 to 22.14; p = 0.013)
  • There were no cases of amniotic fluid embolism

CONCLUSION:

  • The use of cell salvage did not significantly reduce use of donor blood transfusion in all women undergoing cesarean section
    • Emergency cesarean sections have higher blood loss and transfusion is usually the mainstay of treatment to treat hemorrhage
    • The potential for benefit in this group merits confirmation through additional research
  • Cell salvage was associated with increased maternal exposure to fetal blood among RhD-negative mothers
    • Authors expressed caution in interpreting these results as there were large rates of missing data
    • Additional doses of anti-D following birth of an RhD-positive baby to an RhD-negative mother after cell salvage may be required

Learn More – Primary Sources:

Cell salvage and donor blood transfusion during cesarean section: A pragmatic, multicentre randomised controlled trial (SALVO). 

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