RT Journal Article
SR Electronic
T1 Assessment of the voluntary activation of the diaphragm using cervical and cortical magnetic stimulation
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 1224
OP 1231
DO 10.1183/09031936.96.09061224
VO 9
IS 6
A1 T Similowski
A1 A Duguet
A1 C Straus
A1 V Attali
A1 D Boisteanu
A1 JP Derenne
YR 1996
UL http://erj.ersjournals.com/content/9/6/1224.abstract
AB The twitch occlusion technique is a promising tool for use in accessing central drive to the diaphragm and determining maximal transdiaphragmatic pressure (Pdi) from submaximal efforts. It clinical use is limited by difficulties inherent to bilateral electrical stimulation (BES) of the phrenic nerves. This study was designed to revisit the technique using cervical magnetic stimulation (CMS). In addition, the effects of a voluntary contraction on diaphragm response to magnetic stimulation of the cortex (CxMS) were studied. Seven volunteers aged 23-33 yrs were studied. Pdi was determined at relaxed functional residual capacity (FRC) in response to BES (Pdi,P-ES) and CMS (Pdi,p-CMS), and the effects of an increasing voluntary contraction (Pdi, vol) were assessed, The same procedure was applied to CxMS. Pdi,p-CMS at relaxed FRC was 27.5 +/- 2.2 cmH2O (mean+/-SEM), about 20% higher than Pdi,p-ES, and reported previously. Pd,p-CMS linearly decreased with Pdi, vol, and six out of seven subjects were capable of producing voluntary contractions sufficient to extinguish the twitch. More complex patterns were observed with CxMS. Cervical magnetic stimulation provides diaphragmatic twitch occlusion data very similar to bilateral electrical phrenic stimulation. Magnetic stimulation, be it cervical or cortical, could probably be helpful for the assessment of central and peripheral mechanisms of diaphragmatic dysfunction in the clinical setting.