A New Ultrasonographic Tool to Assess Regional Pulmonary Strain

Mechanical Ventilation Complication Clinical Trial

Official title:

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

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT03092557
• Other study ID #: 16.386
• Status: Completed
• Phase: N/A
• First received: March 12, 2017
• Last updated: October 26, 2017
• Start date: July 24, 2017
• Est. completion date: October 26, 2017

Study information

• Verified date: October 2017
• Source: Centre hospitalier de l'Université de Montréal (CHUM)
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 10
• Est. completion date: October 26, 2017
• Est. primary completion date: October 26, 2017
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

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)

Related Conditions & MeSH terms

• Lung Injury
• Mechanical Ventilation Complication
• Ventilator-Induced Lung Injury

Intervention

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.

Locations

Country	Name	City	State
Canada	Centre Hospitalier de l'Université de Montréal (CHUM)	Montreal	Quebec

Sponsors (1)

Lead Sponsor	Collaborator
Centre hospitalier de l'Université de Montréal (CHUM)

Country where clinical trial is conducted

Canada, 

Outcome

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