[Measurement of diaphragm compound muscle action potential with magnetic stimulation of the phrenic nerve and multipara esophageal electrode in intensive care unit].
OBJECTIVE
To investigate whether magnetic stimulation of the phrenic nerve and multipara esophageal electrode can be used to measure diaphragm compound muscle action potential (CMAP) in intensive care unit (ICU).


METHODS
Ten normal subjects and 10 patients in ICU were studied. A newly designed multipara esophageal catheter with 5 pairs of electrodes was used to record the diaphragm CMAP elicited by magnetic stimulation and transcutaneous electrical stimulation of the phrenic nerve.


RESULTS
Good quality CMAPs were obtained from normal subjects and patients in ICU. In normal subjects, the phrenic nerve conduction time (PNCT) and amplitude of the diaphragm CMAP measured with electrical stimulation [(7.2 +/- 0.8) ms, (1.52 +/- 0.40) mV] were similar to those measured with magnetic stimulation [(7.1 +/- 0.8) ms, (1.56 +/- 0.38) mV, all P > 0.05, pooled left and right values]. The amplitude of the diaphragm CMAP in patients [(0.73 +/- 0.38) mV] was much smaller than that in normal subjects [(1.58 +/- 0.38) mV, P < 0.01, pooled left and right values].


CONCLUSIONS
This study suggests that magnetic stimulation combined with a multipara esophageal electrode could be a useful technique in assessing diaphragm function in ICU.
Luo
Yuan-ming
YM
Guangzhou Institute of Respiratory Diseases, First Hospital Affiliated, Guangzhou Medical College, Guangzhou 510120, China.
Chen
Rong-chang
RC
Zhong
Nan-shan
NS
D000200:Action Potentials / Q000528:radiation effects*; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003422:Critical Care; D003964:Diaphragm / Q000294:innervation / Q000503:physiopathology* / Q000528:radiation effects*; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D010791:Phrenic Nerve / Q000503:physiopathology* / Q000528:radiation effects*; D055815:Young Adult