Height Measurement Procedures Influence the Risk of Ventilator-induced Lung Injury in ARDS (SIZE-ARDS)

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.

Study Overview

• Status: Not yet recruiting
• Conditions: Acute Respiratory Distress Syndrome; Ventilator-Induced Lung Injury; Height; Tidal Volume; Predicted Body Weight
• Intervention / Treatment: Other: height measured

• Study Type: Interventional
• Enrollment (Estimated): 39
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Clement Brault, MD; Phone Number: 33+322087831; Email: brault.clement@chu-amiens.fr

Study Locations

• France
  • Amiens, France, 80480
    • CHU Amiens
    • Contact: Clement Brault, MD; Phone Number: 33+322087831; Email: brault.clement@chu-amiens.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: ards patients

Other: height 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pulmonary stress	Pulmonary stress assessed by measuring end-inspiration transpulmonary pressure using a balloon esophageal probe.	one day

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
measured height variation	Agreement of measured height across the different height-measurement methods.	one day
predicted body weight variation	Agreement of predicted body weight across the different height-measurement methods.	one day
tidal volume variation	Agreement of tidal volume across the different height-measurement methods.	one day
Transpulmonary pressures at end-expiratory		one day
Transpulmonary pressures at end-inspiratory intervals.		one day

Collaborators and Investigators

• Sponsor: Centre Hospitalier Universitaire, Amiens

Study record dates

Study Major Dates

• Study Start (Estimated): May 1, 2026
• Primary Completion (Estimated): May 1, 2028
• Study Completion (Estimated): May 1, 2028

Study Registration Dates

• First Submitted: April 28, 2026
• First Submitted That Met QC Criteria: May 12, 2026
• First Posted (Actual): May 19, 2026

Study Record Updates

• Last Update Posted (Actual): May 19, 2026
• Last Update Submitted That Met QC Criteria: May 12, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: acute respiratory distress syndrome; tidal volume; ventilator-induced lung injury; height; predicted body weight
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Respiration Disorders; Lung Injury; Respiratory Distress Syndrome; Ventilator-Induced Lung Injury
• Other Study ID Numbers: PI2026_843_0061

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No