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OpenTrials
Completed

NCT Number: NCT04194346

Determination of Normal Values of Regional Pulmonary Strain Using a New Ultrasonographic Tool in Healthy Volunteers

Mechanical ventilation is frequently used in the operating room and the intensive care settings. Although essential in many cases, mechanical ventilation can be responsible for ventilator-induced lung injury (VILI). The relationship between mechanical ventilation and VILI has been clearly demonstrated in animals and is highly suspected in humans. The putative mechanism responsible for VILI is excessive pulmonary strain or overdistension. Frequently observed in mechanically ventilated patients, the presence of a severe pre-existing pulmonary disease can increase the risk of overdistension. The development of a tool allowing early detection of pulmonary overdistension would represent a great asset in the prevention of VILI by allowing safer adjustments of mechanical ventilation parameters. Ultrasonographic imaging is a non-radiant, non-invasive technique already available in the intensive care setting. Already used for cardiac strain measurements, ultrasonography is a promising avenue to assess pulmonary strain.This study will aim to establish normal pleural strain values using ultrasonography in healthy volunteers.

Purpose: The primary objective is to calculate 95% confidence intervals in pleural strain for a set of 8 inspired volumes at 15 predetermined lung areas in healthy volunteers.

The secondary objectives of the study are:

* to modelize the relation between pleural strain and inspired volume * to modelize the relation between pleural strain and global pulmonary volumetric strain * to modelize the relation between pleural strain and maximal echo intensity change * to compare the regional distribution pattern of pleural strain in healthy volunteers in dependent versus non-dependent areas.

Hypothesis: Elastography using the Lagrangian speckle model estimator based on optical flow allows the determination of normal mean values and 95% confidence intervals of pleural strain (average Von Mises coefficient) in 15 predetermined lung areas for a set of 8 inspired volumes in healthy volunteers.

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Key information

Conditions

Mechanical Ventilation Complication

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Centre Hospitalier de l'Université de Montréal (CHUM)

Montreal, Quebec, H2X 3E4, Canada

About this study

Participants will have their functional residual capacity (FRC) measured by a nitrogen dilution technique. Subsequently, they will be instructed to breathe 8 different inspired volumes (5 to 15 ml/kg predicted body weight). Tidal volumes will be measured using a spirometer. For each inspired volume, 3 respiratory cycles will be recorded at 15 predetermined anatomic sites: 1st and 3rd left and right intercostal spaces at the mid-clavicular line, 5th right intercostal space at the mid-clavicular line, 2nd, 4th and 6th left and right intercostal spaces at the anterior axillary line, and 5th and 7th left intercostal spaces and right to the posterior axillary line. For each image, the probe will be oriented perpendicularly to the ribs. A research, non-commercially available, non-invasive vascular elastography platform will be used to calculate the various strain parameters for all of the recorded cineloops. For each recorded clip, an experienced lung ultrasonographer will segment the pleura on a single reference image. From this image, an algorithm will define a region of interest which will be tracked throughout the rest of the images of the video sequence. Finally, the algorithm will calculate the various components of pleural strain.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Healthy volunteers (20 men/20 women)
  • 18 years old and over
  • Functional capacity superior to 4 METs (metabolic equivalent of task)

Exclusion criteria

  • Previous thoracic procedure (chest tube, thoracotomy, thoracoscopy)
  • Pre-existing pulmonary disease (asthma, chronic obstructive pulmonary disease, lung fibrosis)
  • Active or previous history of smoking
  • Obesity (Body Mass Index superior to 30 kg/m2)

Treatment and study plan

Lung ultrasound

Procedure

Healthy volunteers will have lung ultrasonography at 15 predetermined sites for a common volume continuum between 5 and 15 cc/kg. For each volume, 3 respiratory cycles will be recorded.

Primary outcomes

  1. Average Von Mises

    Time frame: At the end of the study on Day 1

    Three respiratory cycles will be analyzed using an elastography technique based on optical flow to calculate the average Von Mises coefficient. The mean value will be retained.

Secondary outcomes

  1. Sum of the ranges of cumulated absolute axial and cumulated absolute lateral deformation

    Time frame: At the end of the study on Day 1

    Three respiratory cycles will be analyzed using an elastography technique based on optical flow to calculate the sum of the ranges of cumulated absolute axial and cumulated absolute lateral deformation in percentage for each cycle. The mean value will be retained.

  2. Range of cumulated absolute lateral deformation

    Time frame: At the end of the study on Day 1

    Three respiratory cycles will be analyzed using an elastography technique based on optical flow to calculate the range of cumulated absolute lateral deformation in percentage for each respiratory cycle. The mean value will be retained.

  3. Cumulated absolute lateral translation

    Time frame: At the end of the study on Day 1

    Three respiratory cycles will be analyzed using an elastography technique based on optical flow to calculate the cumulated absolute lateral translation in millimeters for each respiratory cycle. The mean value will be retained.

  4. Maximal echo intensity change

    Time frame: At the end of the study on Day 1

    Three respiratory cycles will be analyzed to calculate the maximal echo intensity change using an ordinal scale from 0 to 255. The mean value will be retained.

Sponsors and collaborators

Lead sponsor

Centre hospitalier de l'Université de Montréal (CHUM)

Other

Registry information

Acronym: Strain

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Dec 11, 2019
Registry last updated
Mar 5, 2026

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

View the official ClinicalTrials.gov record (opens in a new tab)

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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