Diaphragm Pacing in Individuals With Spinal Cord Injuries

Study Overview
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Brief Summary
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This project will evaluate the effects of intramuscular diaphragm stimulation (pacing) and test the hypothesis that diaphragm pacing enhances neuromuscular diaphragm activation and respiratory function in adults with cervical spinal cord injuries (C-SCIs). The investigators will test the hypothesis by recording activity of the diaphragm from intramuscular pacing electrodes and conduct respiratory assessments in adults with intramuscular diaphragm pacing electrodes following acute, traumatic C-SCIs.

Detailed Description
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Respiratory dysfunction is a leading cause of death in individuals with spinal cord injuries (SCIs). Nearly one-quarter of all SCI cases involve injury to the upper spinal cord segments which impairs neural activation of the diaphragm muscle and compromises breathing. Although mechanical ventilation can be life-saving after cervical SCI (C-SCI), it also triggers rapid and profound diaphragm muscle atrophy, thereby complicating (or even preventing) ventilator weaning. Intramuscular diaphragm stimulation, or diaphragm pacing, was developed to replace long-term ventilator support and is now used acutely post C-SCI (<4 months following injury) to promote ventilator weaning. This study will assess the effects of diaphragm stimulation on respiratory neural drive and breathing function in individuals with acute, traumatic C-SCI. Recording from these surgically implanted electrodes allows comparisons of electromyogram (EMG) recordings, in association with respiratory assessments, before and after short periods of diaphragm pacing to isolate the unique contribution of diaphragm pacing on neuromuscular diaphragm activation.

Official Title
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Diaphragm Stimulation After Human Spinal Cord Injury: Effects on Respiratory Neural Drive and Function

Conditions
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Cervical Spinal Cord Injury

Intervention / Treatment
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* Device: Diaphragm Pacing


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Acute, traumatic cervical spinal cord injuries (C-SCIs), classified according to the American Spinal Injury Association (ASIA) Impairment Scale (AIS) as A-C Scheduled to undergo implantation of a diaphragm pacer, or who have recently received (in past 5-days) implantation of intramuscular diaphragm pacing electrodes due to severe respiratory impairments and dependence on mechanical ventilation Exclusion Criteria: Progressive neuromuscular diseases such as multiple sclerosis and myasthenia gravis History of neurologic injuries such as stroke or prior SCI Chest wall injuries or deformities likely to influence breathing Pregnancy Cognitive impairments limiting study participation

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Cervical SCI<br>Participants with acute, traumatic cervical spinal cord injuries (C-SCIs), classified according to the American Spinal Injury Association (ASIA) Impairment Scale (AIS) as A-C (complete SCI (A); motor complete SCI (B); motor incomplete with minimal motor function (C)), affecting C1-C6 spinal cord segments, and who have been scheduled to undergo implantation of a diaphragm pacer, or who have recently received (in past 5-days) implantation of intramuscular diaphragm pacing electrodes due to severe respiratory impairments and dependence on mechanical ventilation. | Device: Diaphragm Pacing<br>* Intramuscular stimulation of the diaphragm, or diaphragm pacing' is achieved by laparoscopic placement of stimulation wires into each hemidiaphragm. Phrenic motor points on the diaphragm are mapped to optimize electrode placement. The electrodes are threaded into the diaphragm muscle and wire leads are externalized and attached to a stimulation controller.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Electromyogram (EMG) | Neuromuscular activation of the diaphragm will be assessed by recording diaphragm EMGs from the surgically-implanted intramuscular stimulating electrodes. This approach will allow for comparisons of EMG recordings across time. EMGs will be recorded during non-stimulated respiration (diaphragm pacer turned off) and simultaneously with assessments of respiratory function. | Baseline up to 24 hours | 
| Change in Maximal Inspiratory Pressure (MIP) | The Maximum Inspiratory Pressure (MIP) is measured by a device that applies an inspiratory load which provides a resistance. The MIP will be measured in cmH20 and assesses diaphragm strength. MIP will be recorded will be recorded during non-stimulated respiration (diaphragm pacer turned off). | Baseline up to 24 hours | 
| Change in Tidal Volume | The measurement of Tidal Volume is performed through a simple spirometry and is measured in liters. Tidal Volume will be recorded during non-stimulated respiration (diaphragm pacer turned off). | Baseline up to 24 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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SCI, diaphragm pacing, respiratory impairment, diaphragm stimulation