ELECTRICAL-ACTIVITY RECORDED FROM ABDOMINAL SURFACE BEFORE AND AFTER RIGHT HEMICOLECTOMY IN MAN

To explain the origin of the electrical signals obtained from the abdo minal cutaneous surface (electrosplanchnogram, ESG), the ESG was recor ded in 6 patients with carcinoma of the right colon without obstructio n before and after right hemicolectomy. The analysis of colonic electr ical activity was performed by means of spectral analysis that utilize d fast Fourier transform method. Since the colonic electrical signal i s highly complex and it may contain several frequencies concurrently t he spectral frequency components were subdivided in ranges and the dom inant frequency and power were calculated for each range before and af ter surgery. The pattern obtained from power profile, expressed as dif ferences in power percentages before and after surgery, demonstrated t hat there were significant differences in power data from right hemico lectomized patients compared to cholecystectomized ones (p = 0.00001 a nd p = 0.001 in 2.5-3.5 and 3.6-7.5 cpm range, respectively). In parti cular, hemicolectomized patients showed a slight increase of power per centage in the 2.6-3.5 cpm range and a clear reduction in the 3.6-7.5 cpm range. These data suggest that there are several components of col onic origin in the cutaneous ESG signal which, in the right colon, are identifiable in the 3.6-7.5 cpm range.