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CompletedNCT03981393Updated Apr 27, 2021

Cardinality Matching Study of Early v.s. Delayed VV ECMO in Severe Respiratory Failure

An observational study in Acute Respiratory Failure and ECMO, sponsored by University of Cambridge. Completed. Open to participants aged 16 Years and older. Per ClinicalTrials.gov, last updated 2021-04-27.

Sponsored by University of Cambridge · Observational

Study type
Observational
Model
Cohort
Time perspective
Retrospective
Enrollment
667
Ages
16 Years and older
Sex
All
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Study summary

Clinical reasoning and recent data suggest that early use of venovenous extracorporeal membrane oxygenation in refractory respiratory failure may confer a survival advantage.

This retrospective matched study will assess whether patients who received VV ECMO at less severe hypoxaemia had differing outcomes to those who received ECMO with very severe hypoxaemia.

Read the detailed description

VV ECMO is increasingly used in refractory respiratory failure. Despite advances in lung protective ventilation strategies, patients who have severe respiratory failure often develop complications from mechanical ventilation, including volutrauma and barotrauma. ECMO allows gas exchange to occur extracorporeally and may reduce the potential burden of iatrogenic lung injury by allowing a reduction of volume and pressure support - a 'lung rest' strategy. It is theorised that earlier intitiation of ECMO may allow for better outcomes, as there will have been less time for iatrogenic lung injury to occur.

The UK ECMO registry has been collected of patients treated under the NHS England commissioned respiratory ECMO service since 2011. This study has been previously registered and publication is intended shortly.

Patients will be extracted from this registry if they received VV ECMO. Propensity matching scores will be created and patients will be stratified into groups of 'early' vs 'delayed' ECMO, based on their probability of being in either group.

Patients will be divided into cohorts based on the median PaO2/FiO2 ratio at decision to cannulate ('less severe hypoxaemia') and ('very severe hypoxaemia'). Matched cohorts will be created correcting for key confounding factors (age, primary diagnosis, duration of pre-ECMO ventilation and PaCO2), using cardinality matching (a novel technique described by Zubizaretta et al. in 2014) and traditional propensity-score-based methods.

The technique with greater balance and statistical power (as defined by sample size) will be selected for the primary analysis.

Further analyses will assess the relationship between hypoxaemia at decision-to-cannulate and confounding factors as above.

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Conditions studied

  • Acute Respiratory Failure
  • ECMO
03

In context

Respiratory Insufficiency

1,650 studies on the registry are indexed under Respiratory Insufficiency; 296 are open to participants now.

This study's enrollment of 667 is above the median of 100 across 545 observational studies indexed under Respiratory Insufficiency.

Browse Respiratory Insufficiency studies →

Lead sponsor

University of Cambridge is the lead sponsor of 112 studies on the registry; 23 are open to participants now.

Counted across the registry records on this site, refreshed daily.

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Who can participate

Ages eligible
16 Years and older
Sexes eligible
All
Accepts healthy volunteers
No
Sampling method
Non-probability sample

Study population

This is a prespecified secondary analysis of the UK ECMO registry. Inclusion criteria are ultimately at the discretion of each recruiting centre, but includes adult patients with potentially reversible acute respiratory failure without absolute contraindications to ECMO therapy.

Inclusion criteria

  • Patients included in the UK ECMO registry (see previous registration; NCT number awaited; protocol ECMO-001)
  • Patients with VV ECMO

Exclusion criteria

Exclusion Criteria:

  • Patients with inadequate or missing data for creation of propensity score models.
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Study design

Observational model
Cohort
Time perspective
Retrospective
Enrollment
667 participants (actual)
Patient registry
No

Groups and cohorts

  • 'Less severe hypoxaemia'

    PaO2/FiO2 ratio \> 68 mmHg (9.1kPa) at decision-to-cannulate

  • 'Very severe hypoxaemia'

    PaO2/FiO2 ratio ≤ 68 mmHg (9.1kPa) at decision-to-cannulate

06

What researchers measure

Primary outcomes

  1. Survival to ECMO ICU discharge

    Percentage of patients alive at discharge from the ICU at the specialist ECMO centre

    Time frame: Up to 90 days.

Secondary outcomes

  1. Duration of ECMO treatment

    Duration spent supported by active ECMO treatment.

    Time frame: Up to 90 days.

07

Study locations

No study locations are listed for this record.

08

References and documents

Individual participant data

Plan to share: Undecided — Access to IPD is via the UK ECMO network steering group. Enquiries in the first instance can be made to Dr Alain Vuylsteke, at a.vuylsteke@nhs.net

No publications or documents are linked to this record.

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Apr 27, 2021, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
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Registry details

Key details

Study ID
NCT03981393
Lead sponsor
University of Cambridge
Responsible party
Alex Warren (Academic Foundation Doctor, University of Cambridge) — Principal investigator
First posted
Jun 10, 2019
Start date
Dec 1, 2011
Primary completion
Dec 31, 2017
Completion
Mar 31, 2018
Last update
Apr 27, 2021

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Apr 2021. You cannot join it, but the record below documents what was studied.

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