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Differential Activation of Respiratory Muscles during Lower Thoracic High Frequency Spinal Cord Stimulation (HF‐SCS)
Author(s) -
Kowalski Krzysztof E.,
Romaniuk J Richard,
Pawlowski Gary,
DiMarco Anthony F.
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.743.3
Subject(s) - intercostal muscle , medicine , spinal cord , respiratory system , anesthesia , diaphragm (acoustics) , airway , anatomy , stimulation , physics , psychiatry , acoustics , loudspeaker
Objective Lower thoracic HF‐SCS (500 Hz, 1 mA) applied via a single stimulating electrode located on the dorsal surface of the spinal cord at the T9 level results in large positive airway pressures consistent with marked expiratory muscle activation. The purpose of the present study was to evaluate the effects of lower thoracic HF‐SCS on the ventral surface at this spinal level. Methods In 4 anesthetized dogs, HF‐SCS was applied via a stimulating electrode (4 mm disc) positioned on the ventral surface of the spinal cord at the T9 level. Airway pressure generation was monitored before and following spinal sections at the C8 (to eliminate potential diaphragm activation) and subsequently at the T6 (to eliminate potential intercostal muscle activation) levels. Results HF‐SCS (500 Hz, 1 mA) on the ventral surface, results in inspiratory airway pressure generation of 40 ± 3 cmH 2 O. Following complete C8 spinal section, HF‐SCS results in a significant reduction in negative airway pressure generation to 14 ± 1 cmH 2 O (p<0.05). Subsequent section at the T6 level, HF‐SCS results in a positive airway pressure of 10±1 cmH 2 O (p<0.05 when compared to before either section). Conclusion In contrast to dorsal stimulation, lower thoracic ventral HF‐SCS (500 Hz, 1 mA), at T9 results in activation of pathways with connections to both the phrenic and inspiratory intercostal motoneuron pools resulting in the generation of the large negative airway pressures and minimal expiratory muscle activation. Under the experimental conditions of this study, neuronal pathways with connections to the inspiratory and expiratory motoneuron pools are each limited anatomically to specific regions of the spinal cord. These anatomic differences allow for separate activation of the inspiratory and expiratory muscles to restore function. Support or Funding Information Support: Merit Review Award I01‐RX‐001488 from the U.S. Department of Veterans Affairs, Rehabilitation Research and Development Service. Disclosure: Dr. DiMarco holds two U.S. patents for technology related to the content of this abstract: Method and Apparatus for Electrical Activation of the Expiratory Muscles to Restore Cough (5,999,855) and Bipolar Spinal Cord Stimulation to Activate the Expiratory Muscles to Restore Cough (8,751,004). This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .