Cell Salvage and Donor Blood Transfusion during Cesarean Section: A Pragmatic, multicentre Randomised Controlled Trial (SALVO)

Khan KS, Moore PAS, Wilson MJ et al. on behalf of the SALVO study group.

PLoS Medicine, December 2017. Doi.org/10.1371/journal.pmed.1002471

Introduction

  • Increased prevalence of C-sections worldwide
  • Major haemorrhage during C-sections
    • Maternal death
    • Emergency hysterectomy
    • ITU admissions
  • Management of MOH
    • Blood transfusions – low reserves, associated risk
    • Supportive
    • Tranexamic acid
    • Intraoperative cell salvage

Aim of Study

  • Large, pragmatic, multicentre RCT
  • Will routine use of cell salvage during C-section in women at risk of haemorrhage safely reduce need for donor blood transfusion
  • Compare to current standard of care – no routine use of cell salvage

Methodology

  • Study design
    • Multi-centre randomised control trial
    • UK National Research Ethics Committee approval
    • 26 UK obstetric units
  • Participants
    • Women admitted to labour ward for delivery by emergency or elective C section
    • Women with an increased risk haemorrhage (essentially all except maternal request C sections)
    • Age>16y, English speaking
    • Exclusion: CI to cell salvage/blood transfusion e.g. malignancy, sickle cell, social beliefs, rare Abs
    • Informed consent
  • Randomisation
    • Online system – intervention or control
    • Concealment of allocation
    • No blinding of treatment
    • Need for donor blood transfusion determined according to local policies only
  • Procedures
    • Cell salvage set up pre-op vs. routine care
  • Primary outcome: rate of women receiving blood transfusion during or post C-section
  • Secondary outcomes: units of blood, time to mobilisation, length of hospital stay, Hb

Results

  • 3054 participants (June 2013-April 2016)
  • Exclusions for eligibility/consent
  • 3028 participants randomly allocated
  • Equal numbers in both groups
  • Cell salvage group: 50% had blood returned (260ml)
    • (Donor) Transfusion rate 2.5%
  • Control group: cell salvage used in emergency
    • Transfusion rate 3.5%
  • 95% CI, p = 0.056
  • Subgroup analysis
    • 6% transfused in control (emergency C section)
    • 3% transfused in intervention group (emergency)
    • 2% transfused in control (elective C section)
    • 8% transfused in intervention group (elective)
  • Secondary outcomes
    • Small differences in time to mobilisation and length of hospital stay (in favour of cell salvage group)
    • Greater rate of foeto-maternal haemorrhage in cell salvage group for RhD –ve mothers/RhD +ve babies (48% vs. 13%)
  • Adverse reactions
    • Tachycardia/SOB after re-transfusing salvaged blood
    • Hypotension after 600ml salvaged blood
    • No amniotic fluid emboli

Conclusions/Discussions

  • No significant reduction in blood transfusions with use of cell salvage in women at risk of haemorrhage during C-section
  • Cell salvage – increased exposure to foetal blood among RhD –ve mothers
  • Uncertain cost effectiveness
  • Largest trial looking at RCT in area of cell salvage in obstetrics
  • Very low rate of data loss
  • Comparable baselines
  • Diverse sample – age, ethnicity, geographical location
  • 2 adverse reactions associated with leukocyte depletion filters

Stated Limitations from the Study

  • Use of cell salvage in control group in emergencies – may have avoided use of blood transfusion
  • Concern over foeto-maternal haemorrhage based on only 10 events
    • Need adequate prophylaxis (RhD)
  • Cost-effectiveness uncertain
  • Unlikely to apply to all indications for C sections
  • Needs further research re: cost efficacy, benefit clinically, training for doctors and ODPs
  • ?Only for high risk subgroups in specialist centres?

Summary by Dr A Allana. Journal Club 31 May 2018.

 

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