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Inspiratory Intercostal Muscle Activation via Ventral Root Stimulation (VRS) with a Multipolar Electrode
Author(s) -
DiMarco Anthony F.,
Kowalski Krzysztof E.,
Cernanec Kelly,
Romaniuk Richard
Publication year - 2006
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.20.4.a373-a
Subject(s) - forelimb , stimulation , medicine , anatomy , intercostal muscle , biceps , intercostal nerves , anesthesia , respiratory system
Combined upper thoracic epidural VRS and unilateral phrenic nerve stimulation is a clinically useful method of providing long‐term ventilatory support in ventilator dependent tetraplegics. VRS also results in contraction of the muscles of the upper trunk and upper extremities. The purpose of this study was to evaluate the effects of intercostal muscle activation by different electrode combinations in an attempt to reduce upper extremity stimulation while maintaining maximal negative pressure generation. In 3 dogs, VRS was applied with a 4‐lead electrode in the region of the upper thoracic spinal cord. To assess forelimb movement during VRS, elbow joint angle movement (JAM) and evoked compound action potentials (CAP) of 4 forelimb muscles were recorded. Following hyperventilation induced apnea and airway occlusion, the greatest pressure during single lead stimulation (6mA, 50Hz, 0.2ms) was 16±1 cmH 2 O and JAM was 34±2 o . VRS applied with single shocks (6mA) resulted in significant activation of all 4 forelimb muscles. Lower current stimulation (3mA) with a 2‐lead system resulted in no significant reduction in pressure generation (15±2 cmH 2 O, NS) but significant reduction in JAM (4±2 o , p<0.01) and CAPs of each of the forelimb muscles. Stimulation with more than two electrode leads resulted in no significant changes in pressure generation nor reduction of limbs movement. Our results suggest that intercostal muscle pacing with 2–lead electrode system may result in similar maximal pressure generation compared to single lead stimulation but with a significant reduction in upper limb activation and movement (HL34143).