Relation between the bowel electromyogram and the intestinal pressure wave. An experimental study in dogs

A linear regression study is made of the parameters identifying the electrical activity of the small bowel, with the aim of determining those variables most closely related to the type I pressure waves.

A computer system was used for the simultaneous and real time acquisition of the manometric activity (using microballoons implanted in the bowel mucosa) and electromyogram of the intestine (employing bipolar electrodes implanted in the intestinal serosa) in dogs.

Of the electromyogram intestinal parameters studied, those determining signal energy (root mean square voltage and energy) yielded the highest correlation coefficients (0.71 +/- 0.08 in the jejunum and 0.78 +/- 0.06 in the duodenum) to bowel pressure. Peak-to-peak voltage also shows good correlation, though to a lesser degree. The rest of the parameters studied, such as those that measure the duration of the action potential or its number of peaks, yielded poor correlations to pressure.

It is concluded that the energy of the intestinal electromyogram represents the mechanical activity of the small bowel, reflecting intestinal motility, and that the recording of this parameter is not subjected to subjective cutoff values or threshold levels. On the other hand, and unlike in the case of manometric recordings, the signal obtained is free of background interference and noise.