Effects of Positive End-Expiratory Pressure (PEEP) and Prone Positioning in Healthy Volunteers on Venous Hemodynamics Including the Venous Excess Ultrasound (VExUS) Score
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: application of PEEP: starting PEEP = 15 mbar, application of PEEP: starting PEEP = 0 mbar.
- Who it may be relevant to
- Registry conditions: Venous Hemodynamics. Basic parameters: from 18 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Switzerland
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Overview
The hemodynamic effects of proning and PEEP may vary depending on pre- existing cardiac function, lung mechanics, and volume status, and the available evidence remains conflicting. The impact on the VExUS score of these manoeuvres is unclear. This study aims to assess the effects of PEEP in supine and prone position on the VExUS score as well as echocardiographic parameters in a cohort of healthy volunteers.
Detailed description
Venous congestion: characterized by elevated venous pressure and impaired flow through the organs towards the right heart, contributes to organ dysfunction and is associated with adverse outcomes in critically ill patients. Historically, hemodynamic assessment has focused on the arterial side of circulation, giving less attention to venous hemodynamics. However, there is growing evidence that venous congestion is a mediator of adverse outcomes and contributes to end-organ damage. With increasing venous congestion, subsequent venous distension in the splanchnic circulation occurs and the pressure waveform of the right atrium is retrogradely transmitted into the distal venous circulation. The more venous congestion is present, the more pulsatility is transmitted into the periphery. This represents the backbone of the venous excess ultrasound (VExUS) score assessment. The VExUS score assessment therefore represents a multi-organ Doppler approach evaluating venous congestion by measuring the inferior vena cava (IVC) diameter, flow pattern of hepatic veins, portal vein and intra-renal veins by ultrasound.
Heart lung interactions and implications on VExUS: the VExUS score as well as femoral and jugular vein flows are expected to be affected by positive pressure ventilation. The VExUS score correlates with the Mean systemic filling pressure (MSFP) as a surrogate for stressed volume, in other words the proportion of blood which contributes to creating pressure and blood flow. As right atrial pressure is influenced by Positive End-Expiratory Pressure (PEEP), one would expect elevated VExUS Scores with higher PEEP levels.
Influence of position on hemodynamics: conflicting effects on the circulatory system mediated by prone positioning have been described; no data about VExUS Score assessment in prone position is available.
Interventions
- Diagnostic test application of PEEP: starting PEEP = 15 mbar
The application of PEEP will be delivered by a intensive care respirator with dedicated NIV- mode (Hamilton C1, Hamilton Medical AG, Bonaduz Switzerland) via mask (VariFit, Sleepnet Corporation, New Hampshire, USA) available in four sizes (S, M, L, XL). Pressure support will be set at 5 mbar, and trigger will be adjusted according to participants' comfort. Fraction of inspired oxygen will be 0.21. If starting PEEP = 15 mbar: 5 min stepwise increase of PEEP Measurements with decremental PEEP (15 - Diagnostic test application of PEEP: starting PEEP = 0 mbar
The application of PEEP will be delivered by a intensive care respirator with dedicated NIV- mode (Hamilton C1, Hamilton Medical AG, Bonaduz Switzerland) via mask (VariFit, Sleepnet Corporation, New Hampshire, USA) available in four sizes (S, M, L, XL). Pressure support will be set at 5 mbar, and trigger will be adjusted according to participants' comfort. Fraction of inspired oxygen will be 0.21. If starting PEEP = 0 mbar: Measurement with increasing PEEP (0, 5, 10, 15 mbar)
Primary outcome measures
- Change in VExUS score at 0, 5,10 and 15 mbar during non-invasive ventilation (NIV) in the supine position. [Time frame: up to 15 min]
Secondary outcome measures (1)
- Change in VExUS score at 0, 5,10,15 mbar during non-invasive ventilation in the prone position compared to the supine position. [Time frame: up to 15 min]
Eligibility criteria
Inclusion criteria
- Voluntary participants ≥ 18 years in good overall health with no relevant organ dysfunction in their medical history and signed informed consent form.
Exclusion criteria
- Non-French or non-German speakers
- Unable to provide informed consent
- Body mass index > 40kg/m
- Self-reported pregnancy
- History of pneumothorax
- Previously participated in the study
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Allocation
- Randomized
- Model
- Sequential
- Masking
- Open label
- Primary purpose
- Diagnostic
Study locations
Switzerland · 1 center
- University Hospital Basel, Intensive Care Unit — Basel
Identifiers
NCT: NCT07273617 · am25Loosen2; 2025-01745