"Electromagnetical Stimulation of Phrenic Nerve to Generate Contraction of the Diaphragm"
Study Details
Study Description
Brief Summary
The scientific study is intended to show that external non-invasive electromagnetic stimulation can be used to safely and effectively stimulate the phrenic nerve in awake healthy subjects as well as in ventilated, anesthetized patients and that the stimulation can generate a diaphragmatic contraction that generates significant breath volume - a Controlled Own Breath (COB).
Also of interest is the reproducibility of the generated diaphragmatic movements and the reliability of different feedback signals for detecting the generated diaphragmatic contraction. This applies to inspiration and expiration detection for subsequent synchronization mechanisms of the magnetic stimulator for patient-initiated breathing as well as to contraction intensity. Further, the characterization of the position finding process is of great importance, so that technical developments can further simplify the process of coil positioning in the future. The possible occurrence of discomfort and pain sensation will also be investigated in awake healthy volunteers. Different stimulation protocols will be used.
Finally, it will be investigated whether an adjusted coil position still triggers reproducible diaphragmatic contractions after removal and repositioning in the same configuration. The knowledge gained will be used to further develop the technique and to prepare a study in critically ill, ventilated patients where the diaphragmatic muscle is to be treated preventively by stimulating the phrenic nerve, in order to prevent atrophy of the muscle.
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
|
N/A |
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Experimental: Phrenic nerve stimulation with Stimit Activator
|
Device: Stimit Activator
The Stimit Activator Device is composed of three components.
A magnetic stimulator generating current pulses
A novel Stimit coil design optimized for phrenic nerve stimulation
A coil positioning device for quick, easy and reproducible coil positioning
|
Outcome Measures
Primary Outcome Measures
- Change in airway pressure / endpoint Group 1: [During stimulation]
The primary outcome / endpoint is the change in airway pressure at the mouth during stimulation as seen with or without the use of the ventilator
- Discomfort / pain during stimulation measured by Visual Analogue Scale / endpoint Group 1: [During stimulation]
The primary outcome / endpoint is the level of discomfort / pain during stimulation, measured by Visual Analogue Scale(0-100, with 100 being worst pain / discomfort)
- Change in airway pressure / endpoint Group 2: [During stimulation]
The primary outcome / endpoint is the change in airway pressure during stimulation as seen with or without the use of the ventilator during stimulation.
Secondary Outcome Measures
- Diaphragmatic contraction [During stimulation]
Diaphragmatic contraction at 20 percent / 30 percent / 40 percent stimulation intensity at the optimal stimulation site, at 25 Hz and 2s stimulation time
- Feedback signals [During stimulation]
Change of the maximum value of the feedback signals in percent of the maximum depending on the coil position (in 0.5 cm steps; at least 3 steps in each direction)
- Time stimulation start to end [During stimulation]
Time (mean value & standard deviation) between stimulation start and stimulation end (trigger signal start and end) until the feedback signals from: the abdominal belt, the Diaphragm Thickening Fraction ((TFdi) according to standard procedure, measured via ultrasound during stimulation), and the Diaphragm Excursion Signal "respons" (measured by ultrasound during stimulation)
- Correlation stimulation intensity and diaphragm contraction [During stimulation]
Correlation between stimulation intensity (power output in percent) and diaphragm contraction, measured by tidal volume, at the optimal coil position at given frequency (25 Hz) and given stimulation duration
- Optimal stimulation site - distance [During stimulation]
Distance from anatomical landmark (a) to optimal stimulation site (b) and phrenic nerve (c) using ultrasound and between b and c
- Optimal stimulation site - time [During stimulation]
Time from the start of coil positioning to finding a coil positioning which produces the maximum diaphragmatic contraction at a given stimulation intensity and frequency of 25 Hz
- Tidal volumes [During stimulation]
The mean and standard deviation of generated tidal volumes for ten stimulations performed without the subject being ventilated
- Skin reactions / musle activation [During stimulation]
For Group 1: evaluation of stimulation-induced local skin reactions or muscle activation leading to paresthesia in the dental area
- Safety outcome [During stimulation and postoperatively, usually within 2-3 hours]
The safety outcome/ endpoint is the occurrence of the following events during stimulation: Device related Adverse Events Device related Serious Adverse Events
Eligibility Criteria
Criteria
Inclusion Criteria:
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Persons aged > 18 years
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Applicable for Group 2: planned for elective surgery
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No relevant pre-existing conditions - corresponding to American Society of Anesthesiologists (ASA) level of I-II.
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Written informed consent by the patient for participation in the study given
Exclusion Criteria:
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chronic lung diseases (bronchial asthma, COPD)
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known diaphragmatic weakness
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known neurological conditions with motor muscle weakness
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known paralysis of the phrenic nerve
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conditions that limit the mobility of the diaphragm (high intra-abdominal pressure, ascites, BMI >30)
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not able to read and understand the national language German
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skin lesions, infections or strictures in the neck area
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persons with Implanted cardiac support systems (pacemaker, implanted defibrillator)
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persons with implanted medical pumps
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pregnant women
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persons deprived of liberty by administrative or judicial decision or under legal guardianship.
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Participation in another clinical trial
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Applicable for group 2 (intubated and mechanically ventilated) patients: Exclusion criteria at the time of stimulation:
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Unstable patient after induction of anesthesia and intubation
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | Swiss Paraplegic centre | Nottwil | Switzerland |
Sponsors and Collaborators
- Stimit AG
Investigators
- Principal Investigator: Michael Baumberger, MD, Swiss Paraplegic Center Nottwil
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- Stimit swiss I