Diaphragm Ultrasound Measurements With Variations in Modes of Ventilation

Overview

The overall objective of the study is to conduct an observational study involving intensive care unit patients receiving mechanical ventilation and determine if there are differences in diaphragm thickness ultrasound measurements during expiratory and inspiratory phases in a controlled and spontaneous mode.

Study Type

  • Study Type: Observational
  • Study Design
    • Time Perspective: Prospective
  • Study Primary Completion Date: January 6, 2021

Detailed Description

In this study diaphragm ultrasound measurements at end-expiration and peak inspiration phases in assist control and pressure support mode in consented patients admitted to the medical intensive care unit. One-time measurements will be obtained during the first 48hrs that the patients are receiving mechanical ventilation.

Three consecutive images will be obtained by an investigator that is blinded to the mode (controlled vs. spontaneous). Once measurements are obtained, a second investigator will switch to the other mode (controlled vs. spontaneous) and the blinded investigator will obtain three consecutive images after the patient has adjusted to the subsequent mode (one minute). Tidal volumes will be matched between modes as close as possible. The order of modes to ultrasound (controlled then spontaneous or spontaneous then controlled) will be determined by the non-blinded second investigator. Once the ultrasound measurements are obtained by the research team, image acquisition is concluded for the enrolled patient. The ventilator will be programmed back to the original settings determined by the medical ICU team.

The hypothesis is that the end-expiration diaphragm ultrasound measurement will be thicker in spontaneous mode than controlled mode.

Interventions

  • Other: Assist Control Mode and Pressure Support Mode Mechanical Ventilation
    • Diaphragm ultrasound measurements (end expiration and peak inspiration thickness) will be performed in assist control mode and pressure support mode mechanical ventilation in each participant. The participant will thus serve as his/her own control for these interventions.

Arms, Groups and Cohorts

  • Participants receiving mechanical ventilation

Clinical Trial Outcome Measures

Primary Measures

  • End expiratory diaphragm thickness in controlled and spontaneous modes
    • Time Frame: Less than 48 hours after mechanical ventilation
    • Diaphragm ultrasound measurement at end expiration in assist control mode and pressure support mode

Secondary Measures

  • Thickening fraction in controlled and spontaneous modes
    • Time Frame: Less than 48 hours after mechanical ventilation
    • Diaphragm ultrasound measurement at end expiration and inspiration to calculate thickening fraction = (peak inspiration thickness – end expiration thickness)/end expiration thickness in assist control and pressure support mode ventilation
  • Variance in peak inspiration thickness in controlled and spontaneous modes
    • Time Frame: Less than 48 hours after mechanical ventilation
    • Diaphragm ultrasound measurement at peak inspiration in assist control and pressure support
  • p0.1 measurements in controlled and spontaneous modes
    • Time Frame: Less than 48 hours after mechanical ventilation
    • A measure of respiratory drive obtained from the ventilator in assist control and pressure support

Participating in This Clinical Trial

Inclusion Criteria

  • Patients > 18 years of age
  • intubated and mechanically ventilated for < 48 hours at the time of screening

Exclusion Criteria

  • pregnancy
  • history of diaphragmatic paralysis
  • neuromuscular blockade
  • cardiac arrest

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Investigator Details

  • Lead Sponsor
    • University of Chicago
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Contact(s)
    • John P Kress, MD, 773-702-6404, jkress@medicine.bsd.uchicago.edu

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