RESUMO
Objective To evaluate the feasibility of measuring phrenic nerve conduction time(PNCT)and elicited compound muscle action potential(CMAP)of diaphragm with surface electrodes.Methods PNCT and amplitude of diaphragm CMAP elicited by unilateral magnetic stimulation(UMS)of the phrenic nerve were measured with surface electrodes and the results were compared with those measured with oesophageal electrodes.Results (1)PNCT measured with oesophageal electrode was similar to those measured with surface electrode;the amplitude of CMAP measured with oesophageal electrode was higher than those with surface electrode.(2)There was a significant relationship between the amplitudes of right CMAP measured with oesophageal electrode and those with surface electrodes,whereas there was no such relationship for the left side.(3)The PNCT and the amplitude of CMAP were not related to age,height,weight and perimeter of abdomen no matter measured with oesophageal or surface electrodes.Conclusion Surface electrodes is a useful and noninvasive method to evaluate the function of phrenic nerve and diaphragm.