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Physiological Effects of Different Preoxygenation Strategies (PREOXY II)

6. maj 2026 opdateret af: Simon Rauch, Institute of Mountain Emergency Medicine

Physiological Effects of Different Preoxygenation Strategies in Adults and Children: A Comparative Study of NRM and BVM With and Without PEEP

The goal of this clinical trial is to evaluate the performance and physiological effects of different preoxygenation devices in healthy adult and pediatric volunteers (children aged 5-12 years). The study aims to determine how these devices influence oxygen delivery, airway pressure, and cardiopulmonary physiology during preoxygenation.

The main questions it aims to answer are:

  • What fraction of inspired oxygen (FiO₂) is delivered by non-rebreather masks (NRM) compared to bag-valve masks (BVM) with and without positive end-expiratory pressure (PEEP)?
  • How do these devices differ in terms of generated PEEP, inspiratory effort, and their effects on lung ventilation and cardiac function?

Researchers will compare NRM, BVM without PEEP, and BVM with PEEP (each with or without supplemental oxygen via nasal cannula) to evaluate differences in oxygenation and physiological effects.

Participants will:

  • Complete multiple 3-minute preoxygenation sessions using each device in randomized order
  • Breathe spontaneously through each device, with or without additional oxygen via nasal cannula
  • Undergo non-invasive monitoring of oxygen concentration (FiO₂), respiratory parameters, airway pressures, and ultrasound assessment of the lungs, diaphragm, and heart
  • Perform a brief breath-holding maneuver to assess airway pressure generation

Studieoversigt

Status

Rekruttering

Betingelser

Intervention / Behandling

Detaljeret beskrivelse

Hypoxemia is a frequent and potentially life-threatening complication during advanced airway management, associated with adverse outcomes such as hypoxic brain injury, cardiovascular collapse, and death. Effective preoxygenation is essential to increase oxygen reserves and prolong safe apnea time during intubation. Although several devices are routinely used for preoxygenation, including non-rebreather masks (NRM) and bag-valve masks (BVM) with or without positive end-expiratory pressure (PEEP), important uncertainties remain regarding their actual performance and physiological effects.

Current evidence suggests that techniques providing PEEP may improve oxygenation by increasing functional residual capacity, enhancing ventilation of dependent lung regions, and reducing ventilation-perfusion mismatch. However, the relative contribution of FiO₂ delivery versus PEEP, as well as the physiological effects on respiratory mechanics and cardiovascular function, are not fully understood. In addition, it remains unclear whether BVM devices without a dedicated PEEP valve can generate measurable PEEP, and whether patients can generate sufficient inspiratory effort to effectively operate BVM valves without assisted ventilation. Data in pediatric populations are particularly limited.

This randomized crossover study is designed to systematically evaluate the performance of commonly used preoxygenation devices under controlled conditions in healthy adult and pediatric volunteers. By comparing NRM, BVM without PEEP, and BVM with PEEP-with and without supplemental oxygen via nasal cannula-the study aims to characterize differences in oxygen delivery, airway pressure generation, inspiratory effort, and their physiological impact.

The study will focus on key physiological domains, including oxygenation (FiO₂), respiratory mechanics (tidal volume, airway pressures, and diaphragm activity), lung aeration (with particular attention to dependent lung regions), and cardiovascular responses (including right ventricular dimensions and function). Measurements will be obtained using non-invasive monitoring techniques, including gas analysis and ultrasound.

The crossover design allows within-subject comparisons across all study conditions, minimizing inter-individual variability and enabling precise assessment of device-related effects. The findings of this study are expected to improve understanding of the mechanisms and physiological consequences of preoxygenation strategies, with potential implications for optimizing airway management practices in both adult and pediatric populations.

Undersøgelsestype

Interventionel

Tilmelding (Anslået)

30

Fase

  • Ikke anvendelig

Kontakter og lokationer

Dette afsnit indeholder kontaktoplysninger for dem, der udfører undersøgelsen, og oplysninger om, hvor denne undersøgelse udføres.

Studiekontakt

Undersøgelse Kontakt Backup

Studiesteder

  • Italien
    • BZ
      • Bolzano, BZ, Italien, 39100
        • Rekruttering
        • Eurac research, Institute of mountain emergency medicine
        • Kontakt:
        • Kontakt:
        • Underforsker:
          • Ruth Martintoni
        • Ledende efterforsker:
          • Simon Rauch, MD, PhD
        • Ledende efterforsker:
          • Giulia Roveri, MD

Deltagelseskriterier

Forskere leder efter personer, der passer til en bestemt beskrivelse, kaldet berettigelseskriterier. Nogle eksempler på disse kriterier er en persons generelle helbredstilstand eller tidligere behandlinger.

Berettigelseskriterier

Aldre berettiget til at studere

  • Barn
  • Voksen
  • Ældre voksen

Tager imod sunde frivillige

Ja

Beskrivelse

Inclusion Criteria:

  • Adults with an American Society of Anesthesiologists (ASA) physical status score ≤ 2
  • Children aged 5 to 12 years with an ASA physical status score ≤ 2
  • Ability (or legal guardian ability) to provide written informed consent

Exclusion Criteria:

  • Children aged < 5 years or 13 to 18 years
  • ASA physical status score > 2
  • Body mass index (BMI) ≥ 30 kg/m²
  • Known airway pathology or anatomical abnormality that could affect mask fit, ventilation, or oxygenation
  • Presence of an active airway infection at the time of the study
  • Pregnancy
  • Refusal or inability to provide informed consent

Studieplan

Dette afsnit indeholder detaljer om studieplanen, herunder hvordan undersøgelsen er designet, og hvad undersøgelsen måler.

Hvordan er undersøgelsen tilrettelagt?

Design detaljer

  • Primært formål: Forebyggelse
  • Tildeling: Randomiseret
  • Interventionel model: Crossover opgave
  • Maskning: Enkelt

Våben og indgreb

Deltagergruppe / Arm
Intervention / Behandling
Eksperimentel: Nasal Cannula (NC)
Preoxygenation over 3 minutes with a nasal cannula (NC) with supplemental oxygen delivered at 15 L/min, during spontaneous breathing.
Enhed: Nasal cannula (NC)
Preoxygenation performed using a nasal cannula delivering supplemental oxygen at a flow rate of 15 L/min, without the use of an additional mask or ventilation device, during spontaneous breathing.
Eksperimentel: Non-rebreather facemask (NRM)
Preoxygenation over 3 minutes with a Non-rebreather facemask (NRM) with supplemental oxygen delivered at 15 L/min, during spontaneous breathing.
Enhed: Non-rebreather mask (NRM)
Preoxygenation performed using a non-rebreather mask with reservoir, delivering oxygen at a flow rate of 15 L/min. The mask is fitted to ensure an optimal seal, and participants breathe spontaneously without assisted ventilation.
Eksperimentel: Non-rebreather facemask (NRM) plus Nasal Cannula (NC)
Preoxygenation for 3 minutes using a non-rebreather mask (NRM) combined with a nasal cannula delivering supplemental oxygen at 15 L/min for each device, during spontaneous breathing.
Enhed: Non-rebreather mask (NRM) plus Nasal cannula (NC)
Preoxygenation performed using a non-rebreather mask with reservoir, delivering oxygen at a flow rate of 15 L/min, combined with a nasal cannula delivering supplemental oxygen at 15 L/min. The mask is fitted to ensure an optimal seal, and participants breathe spontaneously without assisted ventilation.
Eksperimentel: Bag valve mask (BVM)
Preoxygenation for 3 minutes using a bag-valve-mask (BVM) with supplemental oxygen delivered at 15 L/min, during spontaneous breathing.
Enhed: Bag-valve mask (BVM) without PEEP
Preoxygenation performed using a bag-valve mask without a PEEP valve, delivering oxygen at a flow rate of 15 L/min. The mask is held with a two-handed technique to ensure an airtight seal, without providing assisted ventilation, allowing spontaneous breathing.
Eksperimentel: Bag valve mask (BVM) plus Nasal cannula (NC)
Preoxygenation for 3 minutes using a bag -valve-mask (BVM) combined with a nasal cannula delivering supplemental oxygen at 15 L/min for each device, during spontaneous breathing.
Enhed: Bag-valve mask (BVM) without PEEP + nasal cannula (NC)
Preoxygenation performed using a bag-valve mask without a PEEP valve, delivering oxygen at a flow rate of 15 L/min, combined with a nasal cannula delivering supplemental oxygen at 15 L/min. The mask is held with a two-handed technique to ensure an airtight seal, without providing assisted ventilation, allowing spontaneous breathing.
Eksperimentel: Bag valve mask (BVM) plus PEEP
Preoxygenation for 3 minutes using a bag-valve mask (BVM) with positive end-expiratory pressure (PEEP) set at 10 cmH₂O and supplemental oxygen delivered at 15 L/min, during spontaneous breathing.
Enhed: Bag-valve mask (BVM) with PEEP
Preoxygenation performed using a bag-valve mask equipped with a PEEP valve set at 10 cmH₂O, delivering oxygen at a flow rate of 15 L/min. The mask is held with a two-handed technique to ensure an airtight seal, without assisted ventilation, during spontaneous breathing.
Eksperimentel: Bag valve mask (BVM) plus PEEP plus Nasal Cannula (NC)
Preoxygenation for 3 minutes using a bag-valve mask (BVM) with positive end-expiratory pressure (PEEP) set at 10 cmH₂O, combined with a nasal cannula delivering supplemental oxygen at 15 L/min for each device, during spontaneous breathing.
Enhed: Bag-valve mask (BVM) with PEEP + nasal cannula (NC)
Preoxygenation performed using a bag-valve mask equipped with a PEEP valve set at 10 cmH₂O, delivering oxygen at a flow rate of 15 L/min, combined with a nasal cannula delivering supplemental oxygen at 15 L/min. The mask is held with a two-handed technique to ensure an airtight seal, without assisted ventilation, during spontaneous breathing.

Hvad måler undersøgelsen?

Primære resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Difference in fraction of inspired oxygen (FiO₂) between preoxygenation devices
Tidsramme: During each 3-minute preoxygenation session
Fraction of inspired oxygen (FiO₂) delivered during preoxygenation will be continuously measured at the airway opening using a gas analyzer. FiO₂ values will be recorded breath-by-breath during each 3-minute preoxygenation session under all study conditions. The primary outcome is the difference in mean FiO₂ achieved between the different preoxygenation devices (non-rebreather mask, bag-valve mask without PEEP, and bag-valve mask with PEEP), with and without supplemental oxygen via nasal cannula.
During each 3-minute preoxygenation session

Sekundære resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Positive end-expiratory pressure (PEEP) generated during preoxygenation
Tidsramme: During each 3-minute preoxygenation session
Airway pressures will be continuously measured to quantify the presence and magnitude of PEEP generated during preoxygenation with bag-valve mask (BVM) with and without a dedicated PEEP valve, with and without nasal cannula oxygen supplementation.
During each 3-minute preoxygenation session
Inspiratory effort required to open the BVM valve
Tidsramme: During each 3-minute preoxygenation session
The negative pressure required to open the BVM valve will be measured using airway pressure monitoring, and diaphragm ultrasound parameters (thickening fraction and excursion) will be used as surrogate markers of inspiratory effort.
During each 3-minute preoxygenation session
Ventilation of dependent lung regions
Tidsramme: During each 3-minute preoxygenation session
Lung ultrasound will be used to assess regional ventilation of dependent lung areas, with findings quantified using a validated scoring system to compare the effects of preoxygenation with and without PEEP.
During each 3-minute preoxygenation session
Correlation between FiO₂ and tidal volume
Tidsramme: During each 3-minute preoxygenation session
The relationship between fraction of inspired oxygen (FiO₂) and tidal volume during preoxygenation will be assessed using continuous, breath-by-breath measurements.
During each 3-minute preoxygenation session
Cardiac output
Tidsramme: Baseline and at the end of each 3-minute preoxygenation session
Changes in cardiac output (l/min/m²) will be assessed using echocardiography before and after preoxygenation to evaluate the hemodynamic effects of different devices and PEEP.
Baseline and at the end of each 3-minute preoxygenation session
Changes in right ventricular dimensions
Tidsramme: Baseline and at the end of each 3-minute preoxygenation session
Changes in right ventricular dimensions (mm) will be assessed using echocardiography before and after preoxygenation to evaluate the hemodynamic effects of different devices and PEEP.
Baseline and at the end of each 3-minute preoxygenation session
Right ventricular strain
Tidsramme: Baseline and at the end of each 3-minute preoxygenation session
Changes in right ventricular strain (%) will be assessed using echocardiography before and after preoxygenation to evaluate the hemodynamic effects of different devices and PEEP.
Baseline and at the end of each 3-minute preoxygenation session

Andre resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Airway pressure during breath-holding maneuver
Tidsramme: Immediately following the preoxygenation session with bag-valve mask (with or without PEEP)
Airway pressure generated during a brief voluntary breath-holding maneuver will be measured when oxygen is delivered via nasal cannula under a bag-valve mask (with or without PEEP), to assess potential continuous positive airway pressure generation.
Immediately following the preoxygenation session with bag-valve mask (with or without PEEP)

Samarbejdspartnere og efterforskere

Det er her, du vil finde personer og organisationer, der er involveret i denne undersøgelse.

Sponsor

Institute of Mountain Emergency Medicine

Efterforskere

  • Ledende efterforsker: Simon Rauch, Eurac research, Institute of mountain emergency medicine

Publikationer og nyttige links

Den person, der er ansvarlig for at indtaste oplysninger om undersøgelsen, leverer frivilligt disse publikationer. Disse kan handle om alt relateret til undersøgelsen.

Generelle publikationer

Datoer for undersøgelser

Disse datoer sporer fremskridtene for indsendelser af undersøgelsesrekord og resumeresultater til ClinicalTrials.gov. Studieregistreringer og rapporterede resultater gennemgås af National Library of Medicine (NLM) for at sikre, at de opfylder specifikke kvalitetskontrolstandarder, før de offentliggøres på den offentlige hjemmeside.

Studer store datoer

Studiestart (Anslået)

23. maj 2026

Primær færdiggørelse (Anslået)

30. juni 2026

Studieafslutning (Anslået)

30. juni 2026

Datoer for studieregistrering

Først indsendt

26. april 2026

Først indsendt, der opfyldte QC-kriterier

26. april 2026

Først opslået (Faktiske)

4. maj 2026

Opdateringer af undersøgelsesjournaler

Sidste opdatering sendt (Faktiske)

8. maj 2026

Sidste opdatering indsendt, der opfyldte kvalitetskontrolkriterier

6. maj 2026

Sidst verificeret

1. april 2026

Mere information

Begreber relateret til denne undersøgelse

Nøgleord

Yderligere relevante MeSH-vilkår

Andre undersøgelses-id-numre

  • PREOXY II

Plan for individuelle deltagerdata (IPD)

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INGEN

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