Dynamics of the level of deterministic chaos associated with gastric electrical uncoupling in dogs

This study investigated the impact of gastric electrical uncoupling on the dynamics of the level of deterministic chaos in cutaneous gastric electrica l signals. Eight-channel electrogastrograms (EGG) were recorded from 76 unc onscious dogs. Controlled gastric electrical uncoupling was introduced by c ircumferentially cutting the whole gastric muscle at two different location s. Three separate 30-min EGG recordings were obtained from each dog in the three different states (basal, after the first cut, and after the second cu t). The Lyapunov exponents were calculated from sixteen 6.31-min intervals with 75% overlap obtained from each channel in each state. Inadequate EGG s ignals from which the Lyapunov exponent could not be reliably calculated we re quantitatively discarded. The variance and the standard deviation of the three Lyapunov exponent distributions obtained from each channel were stud ied, and the mean values were subjected to a Student t-test. In 65.6% of al l studied channels, the level of chaos was significantly different (p < 0.0 1) after the first cut compared to the basal state, but no predominant dire ction of variation was observed (47.7% increment vs. 52.5% decrement). Afte r the second cut, 63.6% of the channels studied showed significantly greate r Lyapunov exponent compared to the basal state, and 63.1% exhibited signif icantly greater (p < 0.011 level of chaos compared to the intercut state. T he dynamics of the level of deterministic chaos in canine electrogastrogram s is highly sensitive to severe gastric electrical uncoupling. Moreover, so me channel configurations seem to be more sensitive than others in detectin g uncoupling.