1Voitenkov V.B., 3Komantsev V.N., 1Skripchenko N.V., 2Ekusheva E.V., 1Klimkin A.V.
1Pediatric Research and Clinical Center for Infectious Diseases, St-Petersburg, Russia
2Advanced Training Institute of the Federal Medical Biological Agency, Moscow, Russia
3St.Petersburg Psychoneurological Research Institute, Saint-Petersburg, 192019

Background. In adult population conduction studies parameters of phrenic nerve (its CMAP latency and amplitude) are quite well established. In children, on the contrary, these parameters change with the age and tend to disperse widely. Our goal was to establish our own set of normative data for latency and amplitude of phrenic nerve CMAP in healthy children of different age. Methods. 48 healthy children (mean age 9,19±5,43, range 1-18 years, 28 females, 20 males) were enrolled. Conduction studies were performed with active electrode at xiphoid process and reference at the VII intercostal space, with stimulation at the external edge of the lower third of sternocleidomastoid muscle, with maximum stimulation at 40 mA. Results. Mean CMAP latency in the group was 5,64±1,25 ms and amplitude was 0,66±0,34 μV. As the group was subdivided on age subgroups as follows: 1-2 years (n=7), 3-5 years (n=9), 6-12 years (n=14) and 13-18 years (n=17), CMAP latencies were 4,96±1,94; 5,01±1,13; 5,42±0,84 and 6,44±1,43 ms and CMAP amplitudes were 1,01±0,37; 0,87±0,31; 0,61±0,24 and 0,45±0,21 μV. CMAP amplitudes in very young children aged 1-2 years were significantly (p<0.05) higher than in children aged 6-12 and 13-18 years. Conclusions. Conduction study of the phrenic nerve, if performed properly, is a simple and reliable method. In pediatric population, though, age dynamic and wide range of normative parameters has to be taken into the consideration. In children CMAP amplitude is significantly higher at the age under 2 years than in older ones (6-18 years).