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NCT Number: NCT07798154

Effect of Spontaneous Breathing in APRV Mode on Respiratory Physiology of ARDS Patients

This is a single-center, prospective, randomized, three-period crossover physiological study in adult patients with moderate-to-severe acute respiratory distress syndrome (ARDS, PaO₂/FiO₂ ≤150 mmHg). Each enrolled subject will receive all three APRV ventilation conditions in random sequence: low-level spontaneous breathing (spontaneous minute-ventilation proportion 10%-30%), high-level spontaneous breathing (31%-50%), and fully suppressed spontaneous breathing as control. A 30-minute wash-out period is set between each condition to restore unified physiological baseline. Primary outcome is ventilation-perfusion mismatch percentage (mismatch%) measured by Electrical Impedance Tomography (EIT). Secondary outcomes include EIT-derived pulmonary parameters, respiratory mechanics, hemodynamics, diaphragmatic function and safety profiles. Only short-term, reversible ventilator and sedation adjustments will be performed; routine clinical management remains unchanged throughout the trial.

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Key information

Conditions

Acute Respiratory Distress Syndrome Lung Diseases Respiration Disorders Respiratory Distress Syndrome Respiratory Tract Diseases

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology

Wuhan, Hubei, 430022, China

Location contact

Xiaojing Zou

CONTACT

[email protected]

+86-27-85351606

About this study

Acute respiratory distress syndrome (ARDS) is a life-threatening critical respiratory illness characterized by heterogeneous pulmonary injury and severe ventilation-perfusion mismatch. Airway Pressure Release Ventilation (APRV) permits spontaneous breathing throughout the whole respiratory cycle, which may improve regional ventilation-perfusion matching and hemodynamic status. Nevertheless, excessive spontaneous breathing effort may trigger pendelluft phenomenon, augment regional lung strain and precipitate patient-self-inflicted lung injury (P-SILI). To date, the safe intensity range of spontaneous breathing during APRV for moderate-to-severe ARDS patients has not been well defined.

This single-center, randomized 3-period crossover self-controlled physiological trial enrolls ICU adult patients aged 18-80 years, diagnosed with moderate-to-severe ARDS (PaO₂/FiO₂ ≤ 150 mmHg) within 48-hours of invasive mechanical ventilation. After written informed consent obtained from legal surrogates, subjects will first receive a 60-minute baseline ventilation period following ARDSnet low-tidal-volume pressure-control ventilation strategy under deep sedation without spontaneous breathing. Subsequently, every participant will undergo three APRV intervention states in computer-generated random order: Condition A: APRV with low-intensity spontaneous breathing (spontaneous-contributed minute ventilation 10%-30%); Condition B: APRV with high-intensity spontaneous breathing (31%-50%); Condition C: APRV with fully suppressed spontaneous breathing via deep sedation (RASS -4 to -5). Each intervention maintains target spontaneous-breathing intensity for 30-minute stabilization before data collection. A mandatory 30-minute wash-out phase will be implemented between successive interventions to revert subjects back to baseline pressure-control ventilation and sedation status.

Primary endpoint is the comparison of ventilation-perfusion mismatch percentage (mismatch%, calculated as sum of dead-space fraction and shunt fraction) among three states measured by bedside EIT. Secondary endpoints contain multiple EIT quantitative indices, respiratory mechanics parameters (including esophageal-pressure-derived transpulmonary pressure), hemodynamic and right-ventricular function, diaphragmatic ultrasound indices, arterial blood gas variables. Adverse events related to respiratory, circulatory and operational procedures are closely monitored as safety outcomes.

Planned sample size is 14-16 enrolled participants to achieve 12 evaluable subjects completing all three intervention sequences considering dropout rate. All ventilator and sedation modifications are short-term and reversible; standard clinical therapeutic regimens will not be altered except for study-related procedures. After finishing all three intervention periods, ventilator and sedation settings will be returned to clinical team's discretion. Linear mixed-effect models will be applied for statistical analysis of crossover-design data.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 1. Age ≥18 and ≤80 years old. 2. Diagnosed with moderate-to-severe ARDS according to the 2023 global ARDS definition.
  • Within 48 hours of invasive mechanical ventilation. After 1-hour low-tidal-volume pressure-controlled ventilation following ARDSnet strategy, arterial blood gas shows PaO₂/FiO₂ ≤ 150 mmHg.
  • Written informed consent is obtained from the patient or their legal surrogate decision-maker after full explanation of the study by the principal investigator or authorized study physician.

Exclusion criteria

  • 1. Refractory shock defined as persistent hyperlactatemia and/or prolonged capillary refill time, fluid-resistant, requiring norepinephrine ≥ 0.5 μg/kg/min.
  • Severe chronic medical conditions severely affecting cardiopulmonary function: severe chronic obstructive pulmonary disease, interstitial lung disease, pulmonary embolism, right-heart failure, pulmonary hypertension, or severe arrhythmia.
  • Radiologically confirmed bronchopleural fistula, status post lobectomy, or other major thoracic surgery.
  • Contraindications to electrical impedance tomography (EIT): extensive chest skin injury or infection, implanted cardiac pacemaker or defibrillator, etc.
  • Contraindications for esophageal manometry placement: esophageal obstruction, perforation, severe esophageal varices, etc.
  • Diaphragmatic hernia, severe chest wall deformity, or significant pulmonary bullae.
  • Significant coagulation abnormalities (PT or APTT prolonged ≥2 times upper limit of normal, or INR>2.0) with active bleeding risk.
  • Severe intracranial hypertension (>20 mmHg), severe traumatic brain injury (GCS ≤8), or neuromuscular disorders.
  • Pregnant or breastfeeding women. 10. Patients already receiving ECMO therapy. 11. Expected survival time <24 hours judged by attending physician. 12. Body mass index (BMI) >35 kg/m². 13. Previously enrolled in this study or participating in other interventional clinical trials.

Treatment and study plan

APRV ventilation with low-level spontaneous breathing

Device

APRV ventilation mode, spontaneous-contributed minute-ventilation proportion maintained at 10%-30%. 30-minute stabilization before outcome measurement.

APRV ventilation with high-level spontaneous breathing

Device

APRV ventilation mode, spontaneous-contributed minute-ventilation proportion maintained at 31%-50%. 30-minute stabilization before outcome measurement.

APRV ventilation with fully suppressed spontaneous breathing

Device

APRV ventilation mode, spontaneous breathing fully suppressed by deep sedation (RASS-4 to -5). 30-minute stabilization before outcome measurement.

Primary outcomes

  1. Ventilation-perfusion mismatch percentage (Mismatch%)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Ventilation-perfusion mismatch percentage (Mismatch%), calculated as the sum of dead-space percentage and shunt percentage measured by electrical impedance tomography (EIT). A composite index reflecting overall ventilation-perfusion mismatch, assessed at baseline and under three APRV experimental conditions. Unit: %

Secondary outcomes

  1. Match percentage(match%)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Match percentage derived from electrical impedance tomography (EIT). Unit: %.

  2. Pendelluft amplitude

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Pendelluft amplitude derived from electrical impedance tomography (EIT). Unit: %.

  3. Dead-space percentage

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Dead-space percentage derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.

  4. Shunt percentage

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Intrapulmonary shunt percentage derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.

  5. Global inhomogeneity index (GI)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period

    Global inhomogeneity index (GI) derived from electrical impedance tomography (EIT). Unit: unitless.

  6. Center of ventilation (CoV)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Center of ventilation (CoV) derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.

  7. Tidal recruitment-derecruitment

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Tidal recruitment-derecruitment (Tidal R/D) derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.

  8. Ventilation distribution

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Regional ventilation distribution derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.

  9. Perfusion distribution

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Regional pulmonary perfusion distribution derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.

  10. Peak airway pressure (Ppeak)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Airway peak pressure (Ppeak) measured by mechanical ventilator, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O

  11. Plateau pressure (Pplat)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Airway plateau pressure (Pplat) obtained from end-inspiratory hold maneuver, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O.

  12. Driving pressure (ΔP)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Driving pressure (ΔP) derived from mechanical ventilator measurements. Unit: cmH₂O.

  13. Static respiratory system compliance (Cstat)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Static respiratory system compliance (Cstat), assessed at baseline and under three APRV experimental conditions. Unit: mL/cmH₂O.

  14. End-inspiratory esophageal pressure (PesI)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    End-inspiratory esophageal pressure (PesI) measured by esophageal manometry, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O.

  15. End-expiratory esophageal pressure (PesE)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    End-expiratory esophageal pressure (PesE) measured by esophageal manometry, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O

  16. Esophageal pressure swing (ΔPes)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Esophageal pressure swing (ΔPes) measured by esophageal manometry, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O.

  17. End-inspiratory transpulmonary pressure (PtpI)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    End-inspiratory transpulmonary pressure (PtpI) derived from airway and esophageal pressure measurements. Unit: cmH₂O.

  18. Transpulmonary driving pressure (ΔPtp)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Transpulmonary driving pressure (ΔPtp) derived from airway and esophageal pressure measurements. Unit: cmH₂O.

  19. End-expiratory transpulmonary pressure (PtpE)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    End-expiratory transpulmonary pressure (PtpE) derived from airway and esophageal pressure, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O.

  20. Esophageal pressure-time product per minute (PTPes/min)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Esophageal pressure-time product per minute (PTPes/min) read directly from the ventilator interface. Unit: cmH₂O·s/min.

  21. Dynamic transpulmonary driving pressure (ΔPL,dyn)

    Time frame: At the end of each 30-minute APRV experimental condition (after stabilization)

    Dynamic transpulmonary driving pressure (ΔPL,dyn) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O.

  22. Inspiratory muscle pressure (Pmus)

    Time frame: At the end of each 30-minute APRV experimental condition (after stabilization)

    Inspiratory muscle pressure (Pmus) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O

  23. End-expiratory occlusion pressure (ΔPocc)

    Time frame: At the end of each 30-minute APRV experimental condition (after stabilization)

    End-expiratory occlusion pressure (ΔPocc) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O

  24. Airway occlusion pressure (P0.1)

    Time frame: At the end of each 30-minute APRV experimental condition (after stabilization)

    Airway occlusion pressure (P0.1) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O

  25. Muscular pressure index (PMI)

    Time frame: At the end of each 30-minute APRV experimental condition (after stabilization)

    Muscular pressure index (PMI) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O

  26. Negative inspiratory force (NIF)

    Time frame: At the end of each 30-minute APRV experimental condition (after stabilization)

    Negative inspiratory force (NIF) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O

  27. Heart rate

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Heart rate from continuous bedside monitoring, assessed at baseline and under three APRV experimental conditions. Unit: beats per minute.

  28. Mean arterial pressure (MAP)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Mean arterial pressure (MAP) measured via invasive arterial catheter, assessed at baseline and under three APRV experimental conditions. Unit: mmHg.

  29. Vasopressor dosage (μg/kg/min)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Dosage of vasoactive medications, assessed at baseline and under three APRV experimental conditions. Unit: μg/kg/min

  30. Central venous pressure (CVP)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Central venous pressure (CVP), assessed at baseline and under three APRV experimental conditions. Unit: mmHg.

  31. Right-ventricular fractional area change

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Right-ventricular fractional area change measured by transthoracic echocardiography, assessed at baseline and under three APRV experimental conditions. Unit: %.

  32. Velocity-time-integral (VTI)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Velocity-time-integral (VTI) measured by transthoracic echocardiography, assessed at baseline and under three APRV experimental conditions. Unit: cm.

  33. Tricuspid annular plane systolic excursion (TAPSE)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Tricuspid annular plane systolic excursion (TAPSE) measured by transthoracic echocardiography, assessed at baseline and under three APRV experimental conditions. Unit: mm.

  34. Cardiac output (CO)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Cardiac output (CO) calculated from velocity-time integral (VTI) measured by transthoracic echocardiography, assessed at baseline and under three APRV experimental conditions. Unit: L/min.

  35. Stroke volume (SV)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Stroke volume (SV) calculated from velocity-time-integral (VTI) measured by transthoracic echocardiography, assessed at baseline and under three APRV experimental conditions. Unit: mL.

  36. Diaphragm displacement

    Time frame: At the end of 30-minute APRV experimental conditions with spontaneous breathing effort (after stabilization)

    Diaphragm displacement measured by bedside diaphragm ultrasound, assessed in two out of the three APRV experimental conditions only when spontaneous breathing was present. Unit: mm.

  37. Diaphragm thickening fraction

    Time frame: At the end of 30-minute APRV experimental conditions with spontaneous breathing effort (after stabilization)

    Diaphragm thickening fraction measured by bedside diaphragm ultrasound, assessed in two out of the three APRV experimental conditions only when spontaneous breathing was present. Unit: %.

  38. Lung 12-zone ultrasound score

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Lung ultrasound score based on 12-zone lung ultrasound assessment, assessed at baseline and under three APRV experimental conditions. Unit: unitless.

  39. Overdistension (OD) pixel count

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Pixel count of lung overdistension (OD), exported directly from electrical impedance tomography (EIT) software basic module, averaged over complete respiratory cycles within selected time interval, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: pixels.

  40. Overdistension (OD) proportion

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Proportion of lung overdistension (OD) relative to total lung-region pixels, exported directly from electrical impedance tomography (EIT) software basic module, averaged over complete respiratory cycles within selected time interval, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: %.

  41. Recruitment (CR) pixel count

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Pixel count of lung recruitment (CR), exported directly from electrical impedance tomography (EIT) software basic module, averaged over complete respiratory cycles within selected time interval, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: pixels.

  42. Recruitment (CR) proportion

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Proportion of lung recruitment (CR) relative to total lung-region pixels, exported directly from electrical impedance tomography (EIT) software basic module, averaged over complete respiratory cycles within selected time interval, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: %.

  43. Atelectasis (AT) pixel count

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Pixel count of lung atelectasis (AT), exported directly from electrical impedance tomography (EIT) software basic module, averaged over complete respiratory cycles within selected time interval, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: pixels.

  44. Atelectasis (AT) proportion

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Proportion of lung atelectasis (AT) relative to total lung-region pixels, exported directly from electrical impedance tomography (EIT) software basic module, averaged over complete respiratory cycles within selected time interval, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: %.

Other outcomes

  1. Incidence and severity of adverse events

    Time frame: During each APRV experimental intervention period

    Incidence and severity of adverse events during study interventions, focusing on respiratory events, circulatory events and procedure-related adverse events. Unit: unitless.

  2. Rate of premature intervention discontinuation for safety concerns

    Time frame: During each APRV experimental intervention period

    Rate of premature discontinuation of study interventions due to safety-related reasons. Unit: %.

  3. Inspired oxygen fraction (FiO₂)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Set inspired oxygen fraction, obtained directly from ventilator readings, recorded at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: %.

  4. Arterial pH

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Arterial blood pH measured from arterial blood gas analysis, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: unitless.

  5. Arterial partial pressure of oxygen (PaO₂)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Arterial partial pressure of oxygen measured from arterial blood gas analysis, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: mmHg.

  6. Arterial partial pressure of carbon dioxide (PaCO₂)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Arterial partial pressure of carbon dioxide measured from arterial blood gas analysis, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: mmHg.

  7. Arterial oxygen saturation (SaO₂)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Arterial oxygen saturation measured from arterial blood gas analysis, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: %.

  8. Bicarbonate (HCO₃-)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Serum bicarbonate (HCO₃-) measured from arterial blood gas analysis, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: mmol/L.

  9. Base excess (BE)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Base excess (BE) measured from arterial blood gas analysis, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: mmol/L.

  10. Arterial lactate (Lac)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Arterial lactate (Lac) measured from arterial blood gas analysis, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: mmol/L.

  11. PaO₂/FiO₂ ratio

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    PaO₂/FiO₂ ratio calculated from arterial blood gas analysis, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: unitless.

  12. Alveolar-arterial oxygen difference (A-aDO₂)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Alveolar-arterial oxygen difference calculated from arterial blood gas analysis, measured at baseline (prior to intervention, after stabilization) and at the end of each 30-minute APRV experimental condition (after stabilization). Unit: mmHg.

  13. Correlation analysis among multiple respiratory-hemodynamic-diaphragm parameters

    Time frame: Corresponding study time points

    Explore the correlations among EIT parameters, respiratory mechanics, blood gas analysis, hemodynamics and diaphragm function across three study conditions.

  14. Ventilatory ratio (VR)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Ventilatory ratio (VR), a calculated index reflecting pulmonary dead-space and lung injury severity, is computed from minute ventilation and arterial CO₂ values assessed at baseline and under three APRV experimental conditions. Unit: unitless.

  15. Expired tidal volume (VTe)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Expired tidal volume assessed at baseline and under three APRV experimental conditions. Unit: mL.

  16. Total respiratory rate

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Total respiratory rate assessed at baseline and under three APRV experimental conditions. Unit: breaths/min.

  17. Total minute ventilation

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Total minute ventilation assessed at baseline and under three APRV experimental conditions. Unit: L/min.

  18. Spontaneous minute ventilation

    Time frame: At the end of 30-minute APRV experimental conditions with spontaneous breathing effort (after stabilization)

    Spontaneous component of minute ventilation assessed under two APRV experimental conditions only when spontaneous breathing was present, derived directly from ventilator readings. Unit: L/min.

  19. Proportion of spontaneous minute ventilation

    Time frame: At the end of 30-minute APRV experimental conditions with spontaneous breathing effort (after stabilization)

    Proportion of spontaneous minute ventilation relative to total minute ventilation, calculated under two APRV experimental conditions only when spontaneous breathing was present. Unit: %.

  20. Mechanical power (MP)

    Time frame: Baseline and at the end of each 30-minute experimental condition during the study intervention period.

    Mechanical power of ventilation as an indicator of ventilator-induced lung injury (VILI) risk, obtained directly from ventilator readings at baseline and under three APRV experimental conditions. Unit: J/min.

Study contacts

Contact information is provided by the study sponsor or research team.

Xiaojing Zou

CONTACT

[email protected]

+86-27-85351606

Sponsors and collaborators

Lead sponsor

Union Hospital, Tongji Medical College, Huazhong University of Science and Technology

Other

Registry information

Official study title

A Randomized Controlled Trial Of The Effect Of Spontaneous Breathing In APRV Mode On Respiratory Physiology In Patients With Acute Respiratory Distress Syndrome

Acronym: SBA-APRV

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Sep 1, 2026
Registry last updated
Sep 1, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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