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.