Acute Respiratory Distress Syndrome, Height, Predicted Body Weight, Tidal Volume, Ventilator-Induced Lung Injury
Conditions
Keywords
acute respiratory distress syndrome, ventilator-induced lung injury, tidal volume, predicted body weight, height
Brief summary
Acute respiratory distress syndrome is characterized by heterogeneous lung injury, with dependent regions often collapsed and non-dependent regions relatively well-aerated, forming the so called "baby lung." Mechanical ventilation, while essential, can induce additional lung injury (VILI) via overdistension (baro/volutrauma) or repetitive alveolar collapse (atelectrauma). Protective ventilation strategies with low tidal volumes (VT 6-8 mL/kg predicted body weight, PBW) reduce mortality, but their efficacy relies on accurate PBW estimation, which is derived from patient height. In critical care, height measurement is often challenging, and common methods such as visual estimation or tape measurement can be inaccurate, leading to inappropriate VT settings and increased risk of lung stress and VILI. Alternative methods, including heel-to-knee distance and laser measurement, may offer more precise PBW estimation, yet their impact on lung mechanics in ARDS remains unexplored. This study addresses the knowledge gap by evaluating whether differences in height measurement methods significantly affect lung stress, tidal volume distribution, and ventilatory mechanics in ARDS patients. Patients' heights will be measured using five methods (stadiometer, visual, tape, laser, heel-to knee). Corresponding PBW and tidal volumes (VT = 6 mL/kg PBW) will be calculated and applied in randomized order, each for 30 minutes. Lung stress, ventilatory mechanics, gas exchange, and regional ventilation distribution will be assessed for each VT setting, preceded by a short alveolar recruitment maneuver. During the study, continuous monitoring of hemodynamics and oxygenation will be performed. Ventilatory parameters including plateau pressure, driving pressure, and transpulmonary pressures will be recorded. Electrical impedance tomography will assess regional tidal volume distribution. Each patient's participation is limited to approximately two hours with no further follow-up.
Interventions
OTHERheight measured
Patients with ARDS will have their height measured using five different methods: stadiometer (reference), visual estimation, measuring tape, infrared laser, and heel-to-knee distance. For each height, the predicted body weight (PBW) and corresponding tidal volume (VT = 6 mL/kg PBW) will be calculated and applied in a randomized order, each for 30 minutes. During each VT period, lung stress (end-inspiratory transpulmonary pressure), ventilatory mechanics, gas exchange, and regional ventilation distribution (assessed using electrical impedance tomography) will be assessed. Prior to each VT application, a short alveolar recruitment maneuver will be performed to standardize lung volume.
Sponsors
Centre Hospitalier Universitaire, Amiens
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Adult patient * Mechanical ventilation on volumetric mode * Sedated and curarized patient * Diagnosis of ARDS according to the Berlin criteria * Diagnosis of ARDS \< 48 hours * Signed informed consent * Affiliation with a social security or health insurance scheme
Exclusion criteria
* Patient opposing the use of his/her data for research purposes. * Contraindication to placement of an esophageal balloon catheter (e.g., esophageal fistula, esophageal varices). * Contraindication to strict supine positioning for height measurement (e.g., proven or suspected intracranial hypertension with intracranial pressure \>18 mmHg). * Impossibility of measuring height with the reference method (stadiometer) due to deformity or amputation of both lower limbs. * Patient under guardianship or curatorship, or deprived of liberty. * Pregnant or postpartum patient, or patient currently breastfeeding.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Pulmonary stress | one day | Pulmonary stress assessed by measuring end-inspiration transpulmonary pressure using a balloon esophageal probe. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| measured height variation | one day | Agreement of measured height across the different height-measurement methods. |
| predicted body weight variation | one day | Agreement of predicted body weight across the different height-measurement methods. |
| tidal volume variation | one day | Agreement of tidal volume across the different height-measurement methods. |
| Transpulmonary pressures at end-expiratory | one day | — |
| Transpulmonary pressures at end-inspiratory intervals. | one day | — |
Countries
France
Contacts
CONTACTClément BRAULT, MD
Outcome results
None listed