The Feasibility of Electrical Impedance Tomography to Guide Non-invasive Respiratory Interventions in Chronic Respiratory Disease

The Feasibility of Electrical Impedance Tomography to Guide Non-invasive Respiratory Interventions in Chronic Respiratory Disease

This study aims to use Electrical Impedance Tomography (EIT) to optimise breathing machines for people with problems with their breathing. This might improve their ability to use their breathing machine. By providing real-time pictures of the lungs, EIT can help clinicians tailor breathing machine settings to meet each persons needs.

Long term respiratory failure is a serious condition that causes extreme difficulty breathing. There are a lot of people in the UK with respiratory failure. It costs the NHS a lot of money to support these people. People with long term respiratory failure often spend a lot of time in hospital.

Non-invasive ventilation (NIV) is a key treatment for these patients. NIV is a breathing machine that supports breathing and helps get rid of waste gases (including carbon dioxide) from the lungs. Cough assist helps people to cough and clear secretion. Lots of patients find using breathing machine hard. It can be difficult to set the machines up to suit each persons needs.

Electrical Impedance Tomography (EIT) is a promising technology that provides real-time pictures of the lungs without radiation exposure. A chest belt sends painless, harmless low-level electrical currents through the lungs. This creates an instant picture of the lungs. EIT has shown to be useful in critical care settings to optimise breathing machine settings. EIT in respiratory failure has not been tested.

Project Goal: Assess if Electrical Impedance Tomography (EIT) can make breathing machine settings better for people with respiratory failure.

Objectives:

Work package 1

• Use EIT to look at and adjust settings on breathing machines (NIV).
• Check if adjustments using EIT help patients use their breathing machines more often.
• Ask people if they feel any better with the machine on the new settings
• Ask people about changes in their symptoms after the changes on the machines have been made Work package 2
• Use EIT to observe lung air movement during mechanical insufflation-exsufflation (MI:E).

Project Structure

Recruitment:

We aim to have 20 participants from the Royal Free Hospital. We aim to have 5-10 participants in each part of the study.

Baseline Measurements:

Work package 1 Body metrics, current NIV therapy, transcutaneous CO2 (TcCO2), spirometry, and forced oscillation technique (FOT), capillary blood gas(CBG).

Work package 2 Spirometry, sniff nasal inspiratory pressure (SNIP), and peak cough flow, capillary blood gas.

Interventions:

Work package 1 Use EIT to improve settings on the breathing machine. Patients will wear the EIT belt to get a baseline. Expert clinicians will change breathing machine settings whilst looking at the EIT pictures. New and improved settings will be tested for 2-4 hours. Patients will then be sent home on these new settings and tests will be redone after one month on the new and improved settings.

Work package 2 Use EIT to monitor the effects of MI:E. Participants will undergo five short MI:E sessions of 1-2minutes with a 20minute rest between sessions, with EIT attached, adjusting pressures by 20%. EIT will track the changes in how air moves within the lungs during different MI:E prescriptions.

Data Analysis:

We will compare the tests as baseline and one month follow-up using statistics. The statistical tests will help us work out if using EIT to guide the NIV and M I:E machine settings makes them better for patients.

Inclusion Criteria:

• Work package 1:

  • Patients diagnosed with chronic respiratory failure
  • Requiring domiciliary NIV and non-concordant with NIV (<4hrs/night for 70% in the last 1month)
  • Age ≥18years

Work package 2:

• Age ≥18years
• Patients diagnosed with a neuromuscular disease
• Currently use or have previously used MI:E for clinical use or as part of a research study

Exclusion Criteria:

• Exclusion criteria work package 1:

  • Unable to provide informed consent

  • Contraindication to EIT:

    • Active implantable cardiac device
    • Active pacemaker
    • Open wound over the site of the EIT belt

  • Chest circumference < 80cm or > 116cm

  • Psychosocial factors attributable to non-concordance

  • Excessive mask leak contributing to non-concordance

  • Mental health diagnosis contributing to non-concordance

  • Pregnancy

Exclusion criteria work package 2:

• Unable to provide informed consent

• Contraindication to EIT:

  • Active implantable cardiac device
  • Active pacemaker
  • Open wound over the site of the EIT belt

• Chest circumference < 80cm or > 116cm

• Pregnancy

• Evidence of obstructive airways disease FEV1:FVC<0.7.

  • Contraindication to MI:E:
  • Un-drained pneumothorax.
  • Severe bronchospasm.
  • Head injury with Intercranial pressure (ICP) >25 mm Hg.
  • Severe arterial hypotension (mean arterial pressure <65 mm Hg).
  • Tracheoesophageal fistula.
  • Significant haemoptysis.
  • Facial fractures.
  • Vomiting.
  • Flail segment
  • Epistaxis within 2 weeks.