Читать книгу The Esophagus - Группа авторов - Страница 233

In the early years, combined MII‐EM and high‐resolution manometry (HRM) were developed in competition with one another until technical and software development enabled device companies to offer combined high‐resolution impedance manometry (HRiM) systems.

The combined HRiM gives a unique tool that can assess pressure changes from the hypopharynx to the proximal stomach and decide the effectiveness of esophageal peristalsis to move boluses through the esophagus. The increased number of impedance channels in HRiM allows intraluminal impedance to be displayed as a color contour plot. The display of the impedance data can be done by overlaying data from individual impedance‐measuring segments on the pressure topography colors (Figure 9.4). Impedance is displayed using a single‐color gradient (i.e. gray or purple) to overlay on pressure data or using split screens. In contrast to the line tracing of the conventional intraluminal impedance, complete bolus transit is defined in the color contour plot by the absence of residual bolus color after a swallow, allowing a more reproducible and easier interpretation [32]. A study of 10 healthy volunteers using concurrent videofluoroscopy with color contour plot measured an esophageal impedance integral. The study showed that the ratio of the esophageal impedance integral before and after the swallow‐induced peristaltic wave front correlated well with the flow of the barium; however, a specific volume of retained barium could not be calculated. In conclusion, impedance technology may still reflect physiologic amounts of residual fluid in the esophagus, or it conversely underestimates larger volumes [33].