A New Ultrasonographic Tool to Assess Regional Pulmonary Strain

A Pilot Study of a New Ultrasonographic Tool to Assess Regional Pulmonary Strain in Patients Under General Anesthesia

This study is designed to assess the feasibility of the measurement of local pleural strain at 4 different anatomical sites.

The secondary objectives of the study are:

• To assess intra- and inter-observer variability in the measurement of local pleural strain
• To identify the strain parameters demonstrating the most clinically relevant and the most significant correlation with a change in tidal volume

Hypothesis: The analysis of lung ultrasonographic sequences using speckle-tracking allows the determination of local pleural strain in 4 predetermined pulmonary areas.

Study Overview

• Status: Completed
• Conditions: Ventilator-Induced Lung Injury; Mechanical Ventilation Complication
• Intervention / Treatment: Other: Determination of local pleural strain

Detailed Description

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 pilot study will aim to assess the feasibility of the measurement of local pleural strain in 4 predetermined pulmonary areas using ultrasonographic imaging.

Following the induction of general anesthesia and the patient's intubation, 4 different tidal volumes of 6 ml/kg, 8ml/kg, 10 ml/kg and 12 ml/kg will be studied. For each volume, images of the pleura will be made at 4 predetermined areas. The sites to be studied will be: the 4th intercostal space at the mid-clavicular line (left and right side), the 7th intercostal space at the posterior axillary line (left and right side). For each tidal volume, 3 consecutive respiratory cycles at each site will be recorded for subsequent analysis.

To assess intra- and inter-observer variability, for the 10 ml/kg tidal volume only, the examination will be immediately repeated by a second observer at the 4 predetermined sites. The first observer will also return to repeat the examination at the same sites.

Mechanical ventilation parameters will be standardized throughout the study as follows: volume-controlled ventilation, respiratory rate at 12 breaths per minute adjusted to obtain expired carbon dioxide (CO2) between 30 and 40 mm Hg, initial inspired oxygen fraction of 40% adjusted between 40% and 80% to obtain oxygen saturation ≥ 92% and positive end-expiratory pressure at 6 cm H2O. In the event of a desaturation (saturation inferior to 90%) despite an increase in inspired oxygen fraction, the study will be stopped and adjustments of mechanical ventilation parameters will be left to the attending anesthesiologist's discretion.

Lung ultrasonography will be performed by the principal investigator and a co-investigator using a Terason (Teratech Corporation, Burlington, MA) device and a 12L5 linear ultrasound probe. For each image, the probe will be oriented perpendicularly to the ribs and pleura with the pointer towards the participant's head. Depth will be adjusted in order to have the pleural line in the center of the screen. The beam's focal zone will be positioned at the level of the pleural line. A 12 megahertz (MHz) frequency will be used.

Using a reference ultrasonographic image, an experienced lung ultrasonographer will segment the pleura. From this image, an algorithm will define a region of interest which will be followed throughout the rest of the images of the video sequence. Thereafter, the algorithm will calculate the various components of pulmonary strain in relation to tidal volume. An experienced technician will visually validate the speckle-tracking.

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Quebec
    • Montreal, Quebec, Canada, H2L 4M1
      • Centre Hospitalier de l'Universite de Montreal (CHUM)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Patients with presumed healthy lungs undergoing elective surgery under general anesthesia requiring neuromuscular blocking agents and orotracheal intubation

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
• Need for supplemental oxygen
• Abnormal pulmonary function tests (when available)
• Obesity (Body Mass Index superior to 30 kg/m2)
• Functional capacity inferior to 4 metabolic equivalent of task (METs)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: OTHER
• Allocation: NA
• Interventional Model: SINGLE_GROUP
• Masking: NONE

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Determination of local pleural strain; Patients will receive four different tidal volumes in random order (6 mL/kg, 8 mL/kg, 10 mL/kg, 12 mL/kg).	Other: Determination of local pleural strain; For each tidal volume, the local pleural strain will be determined over three consecutive respiratory cycles at four predetermined sites using lung ultrasonography.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Feasibility of the measurement of local pleural strain using ultrasonography	Proportion of successfully analyzed lung ultrasonographic clips	At the end of study on Day 1

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intra-observer variability	Agreement and bias will be calculated according to Bland and Altman	At the end of study on Day 1
Inter-observer variability	Agreement and bias will be calculated according to Bland and Altman	At the end of study on Day 1
Maximal axial deformation	Increase from baseline in percentage	At the end of study on Day 1
Maximal lateral deformation	Increase from baseline in percentage	At the end of study on Day 1
Mean magnitude of shear deformation	Increase from baseline in percentage	At the end of study on Day 1
Cumulative axial translation	Difference from baseline in millimeters	At the end of study on Day 1
Cumulative lateral translation	Difference from baseline in millimeters	At the end of study on Day 1

Collaborators and Investigators

• Sponsor: Centre hospitalier de l'Université de Montréal (CHUM)

Publications and helpful links

General Publications

• Girard M, Roy Cardinal MH, Chasse M, Garneau S, Cavayas YA, Cloutier G, Denault AY. Regional pleural strain measurements during mechanical ventilation using ultrasound elastography: A randomized, crossover, proof of concept physiologic study. Front Med (Lausanne). 2022 Sep 15;9:935482. doi: 10.3389/fmed.2022.935482. eCollection 2022.

Study record dates

Study Major Dates

• Study Start (ACTUAL): July 24, 2017
• Primary Completion (ACTUAL): October 26, 2017
• Study Completion (ACTUAL): October 26, 2017

Study Registration Dates

• First Submitted: March 12, 2017
• First Submitted That Met QC Criteria: March 22, 2017
• First Posted (ACTUAL): March 28, 2017

Study Record Updates

• Last Update Posted (ACTUAL): October 30, 2017
• Last Update Submitted That Met QC Criteria: October 26, 2017
• Last Verified: October 1, 2017

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Wounds and Injuries; Thoracic Injuries; Lung Injury; Ventilator-Induced Lung Injury
• Other Study ID Numbers: 16.386

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