Functional magnetic ventilation in dogs.
OBJECTIVE
To investigate the efficacy of the magnetic stimulation of inspiratory muscles as an alternative to mechanical ventilation and functional electric stimulation.


METHODS
A prospective before-after trial.


METHODS
Functional magnetic stimulation laboratory in a Veterans Administration health care system.


METHODS
Six male mongrel dogs, each weighing between 25 and 35 kg.


METHODS
Commercially available magnetic stimulators with a round magnetic coil were used. The center of the magnetic coil was placed posteriorly over the C5-7 vertebrae of the spinal cord transected dogs. Magnetic stimulation parameters were set at 80% intensity, 20 Hz, and a 1.2-second on and 3.8-second off pulse train.


METHODS
The major outcomes were changes in tidal volume (VT), tracheal pressure (Ptr), and arterial partial pressure of carbon dioxide (PaCO2) and oxygen sustained by magnetic stimulation over time.


RESULTS
The average Vt and Ptr produced during functional magnetic ventilation (FMV) were.47+/-.07 L and -4.7+/-.51 cmH2O, respectively. Blood gas data showed that PaCO2 increased from a baseline of 33 to 75 mmHg, whereas pH decreased from 7.33 to 6.99 at the end of the 1-hour FMV period.


CONCLUSIONS
FMV was achieved for 2 hours in dogs with C2 spinal cord transection. Additional refinements in magnetic stimulation are needed to improve ventilation in animals.
Lin
Vernon W
VW
Functional Magnetic Stimulation Laboratory, Spinal Cord Injury-Disorder Health Care Group, Long Beach VA Healthcare System, CA 90822, USA. vernon.lin@med.va.gov
Hsiao
Ian
I
Deng
Xiaoming
X
Lee
Yu-Sheng
YS
Sasse
Scott
S
D000704:Analysis of Variance; D000818:Animals; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000097:blood; D002574:Cervical Vertebrae / Q000293:injuries; D004195:Disease Models, Animal; D004285:Dogs; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000097:blood; D008280:Magnetics / Q000009:adverse effects / Q000295:instrumentation / Q000627:therapeutic use*; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D010791:Phrenic Nerve; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D012131:Respiratory Insufficiency / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D012132:Respiratory Muscles; D013119:Spinal Cord Injuries / Q000150:complications; D013990:Tidal Volume; D013997:Time Factors; D016896:Treatment Outcome; D015919:Ventilators, Negative-Pressure
D002245:Carbon Dioxide; D019344:Lactic Acid; D010100:Oxygen