Validation of improved recording site to measure phrenic conduction from surface electrodes in humans

Similowski. Validation of improved recording site to mea-sure phrenic conduction from surface electrodes in humans. J Appl Physiol 92: 967–974, 2002; 10.1152/japplphysiol. 00652.2001.—Phrenic nerve stimulation, electrical (ES) or from cervical magnetic stimulation (CMS), allows one to assess the diaphragm contractile properties and the conduc-tion time of the phrenic nerve (PNCT) through recording of an electromyographic response, traditionally by using sur-face electrodes. Because of the coactivation of extradiaphrag-matic muscles, signal contamination can jeopardize the de-termination of surface PNCTs. To address this, we compared PNCTs with ES and CMS from surface and needle dia-phragm electrodes in five subjects (10 phrenic nerves). At a modified recording site, lower and more anterior than usual (lowest accessible intercostal space, costochondral junction