[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"health-study-detail:100654304":3},{"organization":4,"outcomesModule":7,"designInfo":212,"detailedDescription":220,"studyPopulation":217,"armGroups":221,"interventions":238,"overallOfficials":252,"centralContacts":256,"locations":262,"responsibleParty":278,"collaborators":217,"id":281,"slug":282,"hasResults":283,"nctId":284,"briefTitle":285,"officialTitle":286,"acronym":287,"eligibilityCriteria":288,"healthyVolunteers":283,"sex":289,"minAge":290,"maxAge":291,"enrollmentInfo":292,"targetDuration":217,"studyType":295,"phases":296,"briefSummary":298,"conditions":299,"keywords":301,"overallStatus":306,"whyStopped":217,"lastUpdateSubmitDate":307,"lastUpdatePostDateStruct":308,"startDateStruct":311,"completionDateStruct":313,"leadSponsor":315,"locationsCount":316},{"fullName":5,"class":6},"Union Hospital, Tongji Medical College, Huazhong University of Science and Technology","OTHER",{"primaryOutcomes":8,"secondaryOutcomes":13,"otherOutcomes":149},[9],{"measure":10,"description":11,"timeFrame":12},"Ventilation-perfusion mismatch percentage (Mismatch%)","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: %","Baseline and at the end of each 30-minute experimental condition during the study intervention period.",[14,17,20,23,26,30,33,36,39,42,45,48,51,54,57,60,63,66,69,72,75,79,82,85,88,91,94,97,100,103,106,109,112,115,118,121,125,128,131,134,137,140,143,146],{"measure":15,"description":16,"timeFrame":12},"Match percentage(match%)","Match percentage derived from electrical impedance tomography (EIT). Unit: %.",{"measure":18,"description":19,"timeFrame":12},"Pendelluft amplitude","Pendelluft amplitude derived from electrical impedance tomography (EIT). Unit: %.",{"measure":21,"description":22,"timeFrame":12},"Dead-space percentage","Dead-space percentage derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.",{"measure":24,"description":25,"timeFrame":12},"Shunt percentage","Intrapulmonary shunt percentage derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.",{"measure":27,"description":28,"timeFrame":29},"Global inhomogeneity index (GI)","Global inhomogeneity index (GI) derived from electrical impedance tomography (EIT). Unit: unitless.","Baseline and at the end of each 30-minute experimental condition during the study intervention period",{"measure":31,"description":32,"timeFrame":12},"Center of ventilation (CoV)","Center of ventilation (CoV) derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.",{"measure":34,"description":35,"timeFrame":12},"Tidal recruitment-derecruitment","Tidal recruitment-derecruitment (Tidal R\u002FD) derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.",{"measure":37,"description":38,"timeFrame":12},"Ventilation distribution","Regional ventilation distribution derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.",{"measure":40,"description":41,"timeFrame":12},"Perfusion distribution","Regional pulmonary perfusion distribution derived from electrical impedance tomography (EIT), assessed at baseline and under three APRV experimental conditions. Unit: %.",{"measure":43,"description":44,"timeFrame":12},"Peak airway pressure (Ppeak)","Airway peak pressure (Ppeak) measured by mechanical ventilator, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O",{"measure":46,"description":47,"timeFrame":12},"Plateau pressure (Pplat)","Airway plateau pressure (Pplat) obtained from end-inspiratory hold maneuver, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O.",{"measure":49,"description":50,"timeFrame":12},"Driving pressure (ΔP)","Driving pressure (ΔP) derived from mechanical ventilator measurements. Unit: cmH₂O.",{"measure":52,"description":53,"timeFrame":12},"Static respiratory system compliance (Cstat)","Static respiratory system compliance (Cstat), assessed at baseline and under three APRV experimental conditions. Unit: mL\u002FcmH₂O.",{"measure":55,"description":56,"timeFrame":12},"End-inspiratory esophageal pressure (PesI)","End-inspiratory esophageal pressure (PesI) measured by esophageal manometry, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O.",{"measure":58,"description":59,"timeFrame":12},"End-expiratory esophageal pressure (PesE)","End-expiratory esophageal pressure (PesE) measured by esophageal manometry, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O",{"measure":61,"description":62,"timeFrame":12},"Esophageal pressure swing (ΔPes)","Esophageal pressure swing (ΔPes) measured by esophageal manometry, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O.",{"measure":64,"description":65,"timeFrame":12},"End-inspiratory transpulmonary pressure (PtpI)","End-inspiratory transpulmonary pressure (PtpI) derived from airway and esophageal pressure measurements. Unit: cmH₂O.",{"measure":67,"description":68,"timeFrame":12},"Transpulmonary driving pressure (ΔPtp)","Transpulmonary driving pressure (ΔPtp) derived from airway and esophageal pressure measurements. Unit: cmH₂O.",{"measure":70,"description":71,"timeFrame":12},"End-expiratory transpulmonary pressure (PtpE)","End-expiratory transpulmonary pressure (PtpE) derived from airway and esophageal pressure, assessed at baseline and under three APRV experimental conditions. Unit: cmH₂O.",{"measure":73,"description":74,"timeFrame":12},"Esophageal pressure-time product per minute (PTPes\u002Fmin)","Esophageal pressure-time product per minute (PTPes\u002Fmin) read directly from the ventilator interface. Unit: cmH₂O·s\u002Fmin.",{"measure":76,"description":77,"timeFrame":78},"Dynamic transpulmonary driving pressure (ΔPL,dyn)","Dynamic transpulmonary driving pressure (ΔPL,dyn) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O.","At the end of each 30-minute APRV experimental condition (after stabilization)",{"measure":80,"description":81,"timeFrame":78},"Inspiratory muscle pressure (Pmus)","Inspiratory muscle pressure (Pmus) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O",{"measure":83,"description":84,"timeFrame":78},"End-expiratory occlusion pressure (ΔPocc)","End-expiratory occlusion pressure (ΔPocc) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O",{"measure":86,"description":87,"timeFrame":78},"Airway occlusion pressure (P0.1)","Airway occlusion pressure (P0.1) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O",{"measure":89,"description":90,"timeFrame":78},"Muscular pressure index (PMI)","Muscular pressure index (PMI) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O",{"measure":92,"description":93,"timeFrame":78},"Negative inspiratory force (NIF)","Negative inspiratory force (NIF) obtained from ventilator measurements; only measured in the presence of spontaneous breathing effort. Unit: cmH₂O",{"measure":95,"description":96,"timeFrame":12},"Heart rate","Heart rate from continuous bedside monitoring, assessed at baseline and under three APRV experimental conditions. Unit: beats per minute.",{"measure":98,"description":99,"timeFrame":12},"Mean arterial pressure (MAP)","Mean arterial pressure (MAP) measured via invasive arterial catheter, assessed at baseline and under three APRV experimental conditions. Unit: mmHg.",{"measure":101,"description":102,"timeFrame":12},"Vasopressor dosage (μg\u002Fkg\u002Fmin)","Dosage of vasoactive medications, assessed at baseline and under three APRV experimental conditions. Unit: μg\u002Fkg\u002Fmin",{"measure":104,"description":105,"timeFrame":12},"Central venous pressure (CVP)","Central venous pressure (CVP), assessed at baseline and under three APRV experimental conditions. Unit: mmHg.",{"measure":107,"description":108,"timeFrame":12},"Right-ventricular fractional area change","Right-ventricular fractional area change measured by transthoracic echocardiography, assessed at baseline and under three APRV experimental conditions. Unit: %.",{"measure":110,"description":111,"timeFrame":12},"Velocity-time-integral (VTI)","Velocity-time-integral (VTI) measured by transthoracic echocardiography, assessed at baseline and under three APRV experimental conditions. Unit: cm.",{"measure":113,"description":114,"timeFrame":12},"Tricuspid annular plane systolic excursion (TAPSE)","Tricuspid annular plane systolic excursion (TAPSE) measured by transthoracic echocardiography, assessed at baseline and under three APRV experimental conditions. Unit: mm.",{"measure":116,"description":117,"timeFrame":12},"Cardiac output (CO)","Cardiac output (CO) calculated from velocity-time integral (VTI) measured by transthoracic echocardiography, assessed at baseline and under three APRV experimental conditions. Unit: L\u002Fmin.",{"measure":119,"description":120,"timeFrame":12},"Stroke volume (SV)","Stroke volume (SV) calculated from velocity-time-integral (VTI) measured by transthoracic echocardiography, assessed at baseline and under three APRV experimental conditions. Unit: mL.",{"measure":122,"description":123,"timeFrame":124},"Diaphragm displacement","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.","At the end of 30-minute APRV experimental conditions with spontaneous breathing effort (after stabilization)",{"measure":126,"description":127,"timeFrame":124},"Diaphragm thickening fraction","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: %.",{"measure":129,"description":130,"timeFrame":12},"Lung 12-zone ultrasound score","Lung ultrasound score based on 12-zone lung ultrasound assessment, assessed at baseline and under three APRV experimental conditions. Unit: unitless.",{"measure":132,"description":133,"timeFrame":12},"Overdistension (OD) pixel count","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.",{"measure":135,"description":136,"timeFrame":12},"Overdistension (OD) proportion","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: %.",{"measure":138,"description":139,"timeFrame":12},"Recruitment (CR) pixel count","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.",{"measure":141,"description":142,"timeFrame":12},"Recruitment (CR) proportion","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: %.",{"measure":144,"description":145,"timeFrame":12},"Atelectasis (AT) pixel count","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.",{"measure":147,"description":148,"timeFrame":12},"Atelectasis (AT) proportion","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: %.",[150,154,157,160,163,166,169,172,175,178,181,184,187,191,194,197,200,203,206,209],{"measure":151,"description":152,"timeFrame":153},"Incidence and severity of adverse events","Incidence and severity of adverse events during study interventions, focusing on respiratory events, circulatory events and procedure-related adverse events. Unit: unitless.","During each APRV experimental intervention period",{"measure":155,"description":156,"timeFrame":153},"Rate of premature intervention discontinuation for safety concerns","Rate of premature discontinuation of study interventions due to safety-related reasons. Unit: %.",{"measure":158,"description":159,"timeFrame":12},"Inspired oxygen fraction (FiO₂)","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: %.",{"measure":161,"description":162,"timeFrame":12},"Arterial pH","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.",{"measure":164,"description":165,"timeFrame":12},"Arterial partial pressure of oxygen (PaO₂)","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.",{"measure":167,"description":168,"timeFrame":12},"Arterial partial pressure of carbon dioxide (PaCO₂)","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.",{"measure":170,"description":171,"timeFrame":12},"Arterial oxygen saturation (SaO₂)","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: %.",{"measure":173,"description":174,"timeFrame":12},"Bicarbonate (HCO₃-)","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\u002FL.",{"measure":176,"description":177,"timeFrame":12},"Base excess (BE)","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\u002FL.",{"measure":179,"description":180,"timeFrame":12},"Arterial lactate (Lac)","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\u002FL.",{"measure":182,"description":183,"timeFrame":12},"PaO₂\u002FFiO₂ ratio","PaO₂\u002FFiO₂ 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.",{"measure":185,"description":186,"timeFrame":12},"Alveolar-arterial oxygen difference (A-aDO₂)","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.",{"measure":188,"description":189,"timeFrame":190},"Correlation analysis among multiple respiratory-hemodynamic-diaphragm parameters","Explore the correlations among EIT parameters, respiratory mechanics, blood gas analysis, hemodynamics and diaphragm function across three study conditions.","Corresponding study time points",{"measure":192,"description":193,"timeFrame":12},"Ventilatory ratio (VR)","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.",{"measure":195,"description":196,"timeFrame":12},"Expired tidal volume (VTe)","Expired tidal volume assessed at baseline and under three APRV experimental conditions. Unit: mL.",{"measure":198,"description":199,"timeFrame":12},"Total respiratory rate","Total respiratory rate assessed at baseline and under three APRV experimental conditions. Unit: breaths\u002Fmin.",{"measure":201,"description":202,"timeFrame":12},"Total minute ventilation","Total minute ventilation assessed at baseline and under three APRV experimental conditions. Unit: L\u002Fmin.",{"measure":204,"description":205,"timeFrame":124},"Spontaneous minute ventilation","Spontaneous component of minute ventilation assessed under two APRV experimental conditions only when spontaneous breathing was present, derived directly from ventilator readings. Unit: L\u002Fmin.",{"measure":207,"description":208,"timeFrame":124},"Proportion of spontaneous minute ventilation","Proportion of spontaneous minute ventilation relative to total minute ventilation, calculated under two APRV experimental conditions only when spontaneous breathing was present. Unit: %.",{"measure":210,"description":211,"timeFrame":12},"Mechanical power (MP)","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\u002Fmin.",{"allocation":213,"interventionModel":214,"interventionModelDescription":215,"primaryPurpose":216,"observationalModel":217,"timePerspective":217,"maskingInfo":218},"RANDOMIZED","CROSSOVER","Each participant receives all three APRV ventilation conditions in random sequence with 30-minute wash-out period between successive conditions. This is a three-period crossover self-controlled physiological study","TREATMENT",null,{"masking":219,"maskingDescription":217,"whoMasked":217},"NONE","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.\n\nThis 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\u002FFiO₂ ≤ 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.\n\nPrimary 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.\n\nPlanned 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.",[222,228,233],{"label":223,"type":224,"description":225,"interventionNames":226},"Low-level spontaneous breathing under APRV","EXPERIMENTAL","APRV ventilation with spontaneous-contributed minute-ventilation proportion maintained at 10%-30%. A stabilization period of 30 minutes is performed before data collection",[227],"Device: APRV ventilation with low-level spontaneous breathing",{"label":229,"type":224,"description":230,"interventionNames":231},"High-level spontaneous breathing under APRV","APRV ventilation with spontaneous-contributed minute-ventilation proportion maintained at 31%-50%. A stabilization period of 30 minutes is performed before data collection.",[232],"Device: APRV ventilation with high-level spontaneous breathing",{"label":234,"type":224,"description":235,"interventionNames":236},"Fully suppressed spontaneous breathing under APRV","APRV ventilation with spontaneous breathing completely suppressed by deep sedation (RASS-4 to -5). A stabilization period of 30 minutes is performed before data collection.",[237],"Device: APRV ventilation with fully suppressed spontaneous breathing",[239,244,248],{"type":240,"name":241,"description":242,"armGroupLabels":243,"otherNames":217},"DEVICE","APRV ventilation with low-level spontaneous breathing","APRV ventilation mode, spontaneous-contributed minute-ventilation proportion maintained at 10%-30%. 30-minute stabilization before outcome measurement.",[223],{"type":240,"name":245,"description":246,"armGroupLabels":247,"otherNames":217},"APRV ventilation with high-level spontaneous breathing","APRV ventilation mode, spontaneous-contributed minute-ventilation proportion maintained at 31%-50%. 30-minute stabilization before outcome measurement.",[229],{"type":240,"name":249,"description":250,"armGroupLabels":251,"otherNames":217},"APRV ventilation with fully suppressed spontaneous breathing","APRV ventilation mode, spontaneous breathing fully suppressed by deep sedation (RASS-4 to -5). 30-minute stabilization before outcome measurement.",[234],[253],{"name":254,"affiliation":5,"role":255},"xiaojing zou, MD","PRINCIPAL_INVESTIGATOR",[257],{"name":258,"role":259,"phone":260,"phoneExt":217,"email":261},"Xiaojing Zou","CONTACT","+86-27-85351606","249126734@qq.com",[263],{"facility":264,"status":217,"city":265,"state":266,"zip":267,"country":268,"countryCode":269,"cosmosGeoPoint":270,"geoPoint":275,"contacts":276},"Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology","Wuhan","Hubei","430022","China","CN",{"type":271,"coordinates":272},"Point",[273,274],114.26667,30.58333,{"lat":274,"lon":273},[277],{"name":258,"role":259,"phone":260,"phoneExt":217,"email":261},{"type":255,"investigatorFullName":279,"investigatorTitle":280,"investigatorAffiliation":5,"oldNameTitle":217,"oldOrganization":217},"XiaoJing Zou,MD","Chief Physician","100654304","effect-of-spontaneous-breathing-in-aprv-mode-on-respiratory-physiology-of-ards-patients-100654304",false,"NCT07798154","Effect of Spontaneous Breathing in APRV Mode on Respiratory Physiology of ARDS Patients","A Randomized Controlled Trial Of The Effect Of Spontaneous Breathing In APRV Mode On Respiratory Physiology In Patients With Acute Respiratory Distress Syndrome","SBA-APRV","Inclusion Criteria:\n\n* 1\\. Age ≥18 and ≤80 years old. 2. Diagnosed with moderate-to-severe ARDS according to the 2023 global ARDS definition.\n\n  3\\. Within 48 hours of invasive mechanical ventilation. After 1-hour low-tidal-volume pressure-controlled ventilation following ARDSnet strategy, arterial blood gas shows PaO₂\u002FFiO₂ ≤ 150 mmHg.\n\n  4\\. 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.\n\nExclusion Criteria:\n\n* 1\\. Refractory shock defined as persistent hyperlactatemia and\u002For prolonged capillary refill time, fluid-resistant, requiring norepinephrine ≥ 0.5 μg\u002Fkg\u002Fmin.\n\n  2\\. 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.\n\n  3\\. Radiologically confirmed bronchopleural fistula, status post lobectomy, or other major thoracic surgery.\n\n  4\\. Contraindications to electrical impedance tomography (EIT): extensive chest skin injury or infection, implanted cardiac pacemaker or defibrillator, etc.\n\n  5\\. Contraindications for esophageal manometry placement: esophageal obstruction, perforation, severe esophageal varices, etc.\n\n  6\\. Diaphragmatic hernia, severe chest wall deformity, or significant pulmonary bullae.\n\n  7\\. Significant coagulation abnormalities (PT or APTT prolonged ≥2 times upper limit of normal, or INR\\>2.0) with active bleeding risk.\n\n  8\\. Severe intracranial hypertension (\\>20 mmHg), severe traumatic brain injury (GCS ≤8), or neuromuscular disorders.\n\n  9\\. Pregnant or breastfeeding women. 10. Patients already receiving ECMO therapy. 11. Expected survival time \\\u003C24 hours judged by attending physician. 12. Body mass index (BMI) \\>35 kg\u002Fm². 13. Previously enrolled in this study or participating in other interventional clinical trials.","ALL","18 Years","80 Years",{"count":293,"type":294},15,"ESTIMATED","INTERVENTIONAL",[297],"NA","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\u002FFiO₂ ≤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.",[300],"Acute Respiratory Distress Syndrome",[302,303,304,305],"Airway Pressure Release Ventilation","spontaneous breathing","electrical impedance tomography","ventilation-perfusion mismatch","NOT_YET_RECRUITING","2026-08-27",{"date":309,"type":310},"2026-09-01","ACTUAL",{"date":312,"type":294},"2026-10-01",{"date":314,"type":294},"2026-12",{"name":5,"class":6},1]