SynthesisCritical care (London, England)2023
Sample size estimation in clinical trials using ventilator-free days as the primary outcome: a systematic review.
Synthesis in Critical care (London, England), 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT06288724 (Potentially MOdifiable Factors To ImproVe Outcomes of Mechanically Ventilated Patients in ICUs in a Low-income Country), which is not on this map. Cited by 13 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Potentially MOdifiable Factors To ImproVe Outcomes of Mechanically Ventilated Patients in ICUs in a Low-income Country: Rationale and Protocol for a Registry-embedded Prospective Observational Study
Who cites it
13 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Composite outcome measures in high-impact critical care randomised controlled trials: a systematic review.Critical care (London, England) · 2024Pooled it
- Alpha2 agonists for sedation to produce better outcomes for adults with critical illness: a synopsis of the A2B RCT with cost-effectiveness and process evaluation.Health technology assessment (Winchester, England) · 2026Trial
- Effect of Ventilator Mode on Ventilator-Free Days in Critically Ill Adults: A Randomized Clinical Trial.Chest · 2025Trial
- What is the optimal approach to analyse ventilator-free days? A simulation study.Critical care (London, England) · 2025Trial
- Factors associated with women authorship over 25 years in high-impact critical care randomized controlled trials: the pipeline is still leaking.Critical care (London, England) · 2025Article
- Beyond the ventilator-free days: review of several estimands.Critical care (London, England) · 2025Review
- Retrospective Analysis of Fungal Isolations in Patients on Veno-Venous Extracorporeal Membrane Oxygenation: The Multicenter RANGER STUDY 2.0.Journal of fungi (Basel, Switzerland) · 2025Article
- Potentially MOdifiable factors To ImproVe outcomes of mechanically Ventilated patients in a low-income country Intensive Care Units (MOTIVATE-ICU): rationale and protocol for a registry-embedded prospective observational study.Critical care science · 2025Article
- A Retrospective, Single-Center Assessment of Changes in Pain, Agitation, and Delirium Management Before and During the COVID-19 Pandemic.Critical care explorations · 2025Article
- Postoperative atrial arrhythmias after bilateral lung transplantation with intraoperative V-A extracorporeal membrane oxygenation: a single-center experience.Frontiers in transplantation · 2025Article
- Retrospective ANalysis of multi-drug resistant Gram-nEgative bacteRia on veno-venous extracorporeal membrane oxygenation. The multicenter RANGER STUDY.Critical care (London, England) · 2024Article
- Challenges and limitations of using ventilator-free days as an outcome in critical care trials.Critical care science · 2024Article
- Effectiveness of analgosedation protocol on duration of mechanical ventilation in adults with trauma: a pragmatic, cluster and randomized study.International journal of clinical trialsArticle
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
7 authors.
Funding
Abstract
backgroundVentilator-free days (VFDs) are a composite endpoint increasingly used as the primary outcome in critical care trials. However, because of the skewed distribution and competitive risk between components, sample size estimation remains challenging. This systematic review was conducted to systematically assess whether the sample size was congruent, as calculated to evaluate VFDs in trials, with VFDs' distribution and the impact of alternative methods on sample size estimation.
methodsA systematic literature search was conducted within the PubMed and Embase databases for randomized clinical trials in adults with VFDs as the primary outcome until December 2021. We focused on peer-reviewed journals with 2021 impact factors greater than five. After reviewing definitions of VFDs, we extracted the sample size and methods used for its estimation. The data were collected by two independent investigators and recorded in a standardized, pilot-tested forms tool. Sample sizes were calculated using alternative statistical approaches, and risks of bias were assessed with the Cochrane risk-of-bias tool.
resultsOf the 26 clinical trials included, 19 (73%) raised "some concerns" when assessing risks of bias. Twenty-four (92%) trials were two-arm superiority trials, and 23 (89%) were conducted at multiple sites. Almost all the trials (96%) were unable to consider the unique distribution of VFDs and death as a competitive risk. Moreover, significant heterogeneity was found in the definitions of VFDs, especially regarding varying start time and type of respiratory support. Methods for sample size estimation were also heterogeneous, and simple models, such as the Mann-Whitney-Wilcoxon rank-sum test, were used in 14 (54%) trials. Finally, the sample sizes calculated varied by a factor of 1.6 to 17.4.
conclusionsA standardized definition and methodology for VFDs, including the use of a core outcome set, seems to be required. Indeed, this could facilitate the interpretation of findings in clinical trials, as well as their construction, especially the sample size estimation which is a trade-off between cost, ethics, and statistical power. Systematic review registration PROSPERO ID: CRD42021282304. Registered 15 December 2021 ( https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021282304 ).
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.