Motor and electrogastrographic activity of the gastric tube formed after esophagectomy

In order to characterize the motor activity of a surgically constructed gastric tube, several hours of ambulatory intraluminal pressure recordings were performed in 6 patients following esophagectomy and gastric tube construction. Whole pressure waves were spectrally analyzed by Fast Fourier Transform (FFT). Simultaneous abdominal and thoracic electrogastrograms (EGGs) were recorded for about 20 min both before and after meals during ambulatory pressure recording. The pressure waves and EGGs for each 20 min recording were analyzed by the maximal entropy method (MEM). While the motility index of the pressure waves decreased after a meal, the 3 cpm component of these waves (2.4-3.7 cpm) increased significantly (n=6, P<0.05). Both bradygastria (0-2.4 cpm) and the duodeno-respiratory component (10-15 cpm) decreased, while the tachygastria component (3.7-10 cpm) increased, although these differences were not significant. The peak power of the gastric tube abdominal EGGs was significantly larger than that of control abdominal or thoracic EGGs in each of the 1 cpm (0-2.4 cpm), 6 cpm (5.0-7.4) and 8 cpm components (7.5-9.9). The thoracic EGG consisted mainly of the 3 cpm component, while the spectral amplitudes of the 1, 6, 8 and 10 cpm components were below 6% of the 3 cpm component. The peak spectral frequency both of the intraluminal pressure waves by FFT and of the thoracic EGGs by MEM occurred within the 3 cpm component. A cross correlation of about 0.2-0.3 occurred between the thoracic EGGs and the intraluminal pressure waves. Thus the gastric tube seems to preserve most of the original gastric motor characteristics and to contribute as a substitute for the original esophagus and stomach.