Personalized Ventilation Based on Ventilation-perfusion Mismatch and Lung Recruitability
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
- This is an observational study: the protocol does not assign a study treatment.
- Who it may be relevant to
- Registry conditions: Respiratory Distress Syndrome, Positive-Pressure Respiration, Mechanical Ventilation. Basic parameters: 18 years — 85 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
- China
- 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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Official title
Personalized Ventilatory Strategy Based on Ventilation-perfusion Mismatch and Lung Recruitability in Moderate-to-severe ARDS Patients
Overview
This observational study will explore the effects of PEEP and position on regional lung ventilation-perfusion mismatch by electrical impedance tomography (EIT) in moderate-to-severe ARDS patients with different lung recruitability.
Detailed description
Acute respiratory distress syndrome (ARDS) is characterized by impaired ventilation-perfusion matching, which not only indicates the severity of the condition but also contributes to ventilation-induced lung injury. Higher positive end-expiratory pressure (PEEP) and prone position could improve ventilation-perfusion mismatch by recruiting collapsed lungs and facilitating more homogeneous ventilation, but these benefits might depend on lung recruitability. The present study aims to elucidate the regional effect of PEEP(low and high) and body position(supine and prone) on the ventilation-perfusion matching. Also endeavors to establish correlations between alterations in ventilation-perfusion matching patterns and the inherent lung recruitability.
Participants will be deeply sedated and paralyzed, ventilated in volume-controlled with protective ventilation (tidal volume=6-8 mL/Kg of predicted body weight and respiratory rate set to obtain normal pH). Then the patients will be sequentially assigned to each of four conditions as follows:
Low PEEP, supine position; High PEEP, supine position; Low PEEP, prone position; High PEEP, prone position. High PEEP and low PEEP is defined as 15 cmH2O and 5 cmH2O (or airway opening pressure, either of which was higher) respectively. Each measurement (e.g., arterial blood gas analysis, respiratory parameters, hemodynamics, EIT measurements) will be performed at least 15 minutes after changing ventilator settings and at least 1 hour after changing body positions. The timing of turning patients from supine to prone position is determined by the clinical team.
To assess lung recruitability, a single-breath derecruitment maneuver will be performed by changing PEEP 15 to 5 cmH2O (or airway opening pressure, either of which was higher) in supine position. Patients with recruitment-inflation ratio over the median value are defined as high recruiters.
EIT data will be collected by standard device (Infinity C500, Drager, Germany) with a sample rate of 50 Hz. The EIT belt will be placed directly below the armpits, between the third and fifth intercostal spaces. This positioning of the EIT belt will be maintained consistently during both supine and prone positions. A bolus of 10 ml 5% NaCl will be injected during a respiratory pause (≥8 s) through the central venous catheter to assess lung ventilation and perfusion distributions. The primary endpoint is EIT-based ventilation-perfusion matching (V/Q match%).
Primary outcome measures
- Ventilation-perfusion matching (V/Q match%) [Time frame: Through study completion (within 24 hours)]
Secondary outcome measures (4)
- percentage of dead space [Time frame: Through study completion (within 24 hours)]
- percentage of shunt [Time frame: Through study completion (within 24 hours)]
- Respiratory system compliance [Time frame: Through study completion (within 24 hours)]
- PaO2/FiO2 ratio [Time frame: Through study completion (within 24 hours)]
Eligibility criteria
Inclusion criteria
- age ≥18 years
- Moderate-to-severe ARDS as per the 2023 ESICM definition
- Undergoing invasive mechanical ventilation
- Planned prone position based on the attending physicians' decisions
- Signed informed consent
Exclusion criteria
- age ≥85 years
- Pregnancy
- Severe hemodynamic instability (> 30% increase in vasopressors in the last 6 hours or norepinephrine > 0.5 µg/kg/min)
- Clinically suspected elevated intracranial pressure (>18 mm Hg)
- Bronchopleural fistula
- Contraindication to EIT monitoring (e.g. burns, pacemaker, thoracic wounds limiting electrode belt placement)
- Severe hypernatremia (>170mmol/L)
- Re-admission of patients already enrolled in this study, or patients who are participating in other studies
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Observational model
- Cohort
Study locations
China · 1 center
- Zhongda Hospital, Southeast University — Nanjing
Identifiers
NCT: NCT06430554 · 2024ZDSYLL044-P01