Closed-loop cervical epidural stimulation partially restores ipsilesional diaphragm EMG after acute C2 hemisection

Respir Physiol Neurobiol, 2024 · DOI: 10.1016/j.resp.2023.104182 · Published: February 1, 2024

Simple Explanation

Cervical spinal cord injuries can cause long-term breathing problems, often requiring mechanical ventilation. This study explores using closed-loop epidural stimulation (CL-ES) to improve breathing after such injuries. The researchers found that a short session of CL-ES in rats with a specific spinal cord injury (C2 hemisection) helped restore activity in the paralyzed part of the diaphragm, the main breathing muscle. These findings suggest that CL-ES could be a valuable treatment for restoring breathing after high cervical spinal cord injuries, potentially reducing the need for long-term mechanical ventilation.

Study Duration

Not specified

Participants

10 female Sprague-Dawley rats

Evidence Level

Not specified

Key Findings

1
CL-ES recovers spontaneous EMG activity acutely after injury.
2
CL-ES can recover spontaneous ipsilesional diaphragm activity, and potentiates contralesional diaphragm EMG.
3
Resection of the phrenic nerve ipsilesional to injury abolished ipsilateral activity even while stimulation continued.

Research Summary

This study investigates the effects of closed-loop epidural stimulation (CL-ES) on restoring diaphragm activity after acute C2 hemisection in anesthetized rats. The results demonstrate that CL-ES can recover spontaneous ipsilesional diaphragm EMG activity and potentiate contralesional activity during stimulation. The acute application of CL-ES did not lead to increased phrenic network excitability as seen in chronic models, but a subset of animals showed continued spontaneous ipsilesional diaphragm activity after stimulation ceased, indicating potential for lasting effects. The study concludes that CL-ES has positive functional benefits for breathing during stimulation and supports its further development as a therapeutic intervention for improving respiration after cervical spinal cord injury.

Practical Implications

Therapeutic potential for SCI

CL-ES shows promise as a therapeutic intervention to rescue breathing after high cervical spinal cord injury, potentially leading to lasting recovery and device independence.

Improved respiratory function

Facilitation of diaphragm activity through CL-ES could translate to improved respiratory function without ventilatory support, even under challenging conditions like hypoxia or hypercapnia.

Potential for ventilator weaning

The model reflects a potential for CL-ES to be used acutely to assist in ventilator weaning, especially given the common use of volatile anesthetics in patients undergoing long-term mechanical ventilation.

Study Limitations

1
The study requires freely breathing animals, precluding traditional mechanical ventilation approaches for fine control of blood gases.
2
The use of isoflurane anesthesia likely influenced the breathing responses of animals.
3
An additional limitation to this study is the use of only female animals.

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