title: Functional magnetic stimulation of the respiratory muscles in dogs.
abstract: This study assessed the ability of functional magnetic stimulation (FMS) to activate the respiratory muscles in dogs. With the animal supine, FMS of the phrenic nerves using a high-speed magnetic stimulator was performed by placing a round magnetic coil (MC) at the carotid triangle. Following hyperventilation-induced apnea, changes in volume (deltaV) and airway pressure (deltaP) against an occluded airway were determined. FMS of the phrenic nerves produced substantial inspired function (deltaV = 373 +/- 20.5 mL and deltaP = -20 +/- 2.0 cm H2O). After bilateral phrenectomies, maximal inspired deltaV (219 +/- 12.2 mL) and deltaP (-10 +/- 1.0 cm H2O) were produced when the MC was placed near the C6-C7 spinous processes, while maximal expired deltaV (-199 +/- 22.5 mL) and deltaP (11 +/- 2.3 cm H2O) were produced following stimulation near the T9-T10 spinous processes. We conclude: (1) FMS of either the phrenic or upper intercostal nerves results in inspired volume production; (2) FMS of the lower intercostal nerves generates expired volume production; and (3) FMS of the respiratory muscles may be a useful noninvasive tool for artificial ventilation and assisted cough in patients with spinal cord injuries or other neurological disorders.
authors.affiliation: Spinal Cord Injury Service, VA Palo Alto Health Care System, California 94304, USA.
authors.forename: V W
authors.initials: VW
authors.lastname: Lin
authors.forename: J R
authors.initials: JR
authors.lastname: Romaniuk
authors.forename: A F
authors.initials: AF
authors.lastname: DiMarco
mesh_terms: D000818:Animals; D003964:Diaphragm / Q000294:innervation / Q000502:physiology*; D004285:Dogs; D004558:Electric Stimulation; D019054:Evoked Potentials, Motor / Q000502:physiology; D007366:Intercostal Muscles / Q000294:innervation / Q000502:physiology*; D007367:Intercostal Nerves / Q000502:physiology*; D008176:Lung Volume Measurements; D008280:Magnetics; D009121:Muscle Denervation; D009431:Neural Conduction / Q000502:physiology; D010791:Phrenic Nerve / Q000502:physiology* / Q000601:surgery; D012119:Respiration / Q000502:physiology