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Completed

NCT Number: NCT04176744

Optimization of Non-invasive Diaphragm Activation Using Magnetic Phrenic Nerve Stimulation

The use of mechanical ventilation (MV) to replace spontaneous breathing has been associated with respiratory muscle dysfunction and lung injury from positive pressure. While using MV in an intensive care unit setting, the diaphragm is unloaded, potentially resulting in early development of diaphragmatic atrophy in as early as 18 hours of complete diaphragm inactivity. These changes in muscle properties result in a decrease in the force generating capability of the muscle, ultimately resulting in difficulty to restore spontaneous breathing and a subsequent prolonged weaning process or failure. A prolonged weaning period is associated with longer duration of MV, which may result in a cascade of further diaphragm dysfunction, weakness, and injury.

Stimulation of the phrenic nerves to produce diaphragm contraction and activity is a possible mechanism to reduce MV related diaphragm dysfunction. Two promising studies have shown the potential of repetitive phrenic nerve stimulation on inducing diaphragm activity in human subjects with trains of pulses via both cervical and bilateral phrenic nerve stimulation. However, neither study provided optimal stimulation settings. As such, the primary purpose of this study is to investigate the optimal settings for noninvasive phrenic nerve stimulation to induce diaphragm contraction.

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Key information

Conditions

Healthy

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Exercise Physiology Lab, Institute of Human Movement Sciences and Sport, ETH Zurich

Zurich, Canton of Zurich, 8057, Switzerland

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Informed Consent as documented by signature
  • Age: 18 - 35 years
  • Non-smoking
  • Healthy
  • Able to communicate in English
  • Normal lung function
  • Normal Body mass index between 18.5 and 24.9 kg/m2
  • Willingness to adhere to the study rules

Exclusion criteria

  • Acute illness or chronic conditions affecting sleep or the performance of the respiratory, cardiovascular, neuromuscular, gastrointestinal or muscle system
  • Women who are pregnant or breast feeding or have the intention to become pregnant during the course of the study
  • Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. of the participant
  • Known or suspected non-compliance, drug or alcohol abuse
  • Intake of medication affecting sleep or the performance of the respiratory, cardiovascular or neuromuscular system or gastrointestinal or muscle system
  • Presence of cardiac pacemaker, implanted defibrillators or implanted neurostimulators
  • Any metal or electronics inside of the body
  • History of seizures or epilepsy
  • Tattoos on the stimulation sites
  • Previous enrolment into the current study

Treatment and study plan

Uni- and bilateral magnetic phrenic nerve stimulation

Other

Uni- and bilateral magnetic phrenic nerve stimulation using different coils, stimulation patterns (frequency, intensity, number of pulses) and locations (neck, chest).

Primary outcomes

  1. Changes in airflow

    Time frame: Continuously measured from 10 sec before until 10 sec after each stimulation. One stimulation lasts for approx. 1 sec.

    Flow will be recorded by a pneumotachometer and averaged over breaths.

  2. Changes in costal diaphragm activity

    Time frame: Continuously measured from 10 sec before until 10 sec after each stimulation. One stimulation lasts for approx. 1 sec.

    Costal diaphragm activity will be continuously recorded via a wireless surface electromyography system.

  3. Changes in transdiaphragmatic pressure

    Time frame: Continuously measured from 10 sec before until 10 sec after each stimulation. One stimulation lasts for approx. 1 sec.

    Transdiaphragmatic pressure changes, i.e. changes in esophageal and gastric pressures, will be measured by a pressure transducer connected to balloon-catheters.

  4. Changes in mouth pressure

    Time frame: Continuously measured from 10 sec before until 10 sec after each stimulation. One stimulation lasts for approx. 1 sec.

    Mouth pressure will be continuously recorded using a differential pressure transducer.

  5. Changes in abdominal movements

    Time frame: Continuously measured from 10 sec before until 10 sec after each stimulation. One stimulation lasts for approx. 1 sec.

    Abdominal movements will be assessed using the respiratory belt strain transducer.

Secondary outcomes

  1. Changes in extradiaphragmatic muscle activity

    Time frame: Continuously measured from 10 sec before until 10 sec after each stimulation. One stimulation lasts for approx. 1 sec.

    Muscle activity will be continuously recorded via a wireless surface electromyography system.

  2. Changes in head, shoulder and arm movements

    Time frame: Continuously measured from 10 sec before until 10 sec after each stimulation. One stimulation lasts for approx. 1 sec.

    Head, shoulder and arm movements will be recorded using wireless acceleration sensors.

  3. Changes in stress related parameters (heart rate, blood pressure, skin conductance)

    Time frame: Continuously measured from 10 sec before until 10 sec after each stimulation. One stimulation lasts for approx. 1 sec.

    Heart rate will will be continuously recorded with electrodes. Blood pressure will be continuously recorded using a non-invasive device. Skin conductance will be continuously recorded with electrodes worn on two fingers.

  4. Perception of pain, paresthesia and distress

    Time frame: Assessed 10 sec after each stimulation. One stimulation lasts for approx. 1 sec.

    Participant subject perception of pain, paresthesia and distress will be evaluated with a visual analogue scales.

Sponsors and collaborators

Lead sponsor

Swiss Federal Institute of Technology

Other

Registry information

Important dates

Study start
2019
Primary completion
2020
Study completion
2020
First posted
Nov 25, 2019
Registry last updated
Aug 12, 2020

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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