[Digital storage and semi-automatic analysis of esophageal pressure signals. Evaluation of a commercialized system...

The aim of this work was to evaluate a new commercially available pressure recording system (PC Polygraf, Synectics) and to compare this system with a classical method using perfused catheters. The PC Polygraf uses microtransducers and allows direct digitized storage and semi-automatic analysis of data. In the first part of this study, manometric assessment was conducted using only perfused catheters. The transducers were connected to both an analog recorder and to a PC Polygraf. Using the two methods of analysis, contraction amplitudes were strongly correlated (r = 0.99; p less than 0.0001) whereas durations were significantly but loosely correlated (r = 0.51; p less than 0.001). Resting LES pressure was significantly correlated (r = 0.87; p less than 0.05). In the second part of this study, simultaneous recordings of esophageal pressure were conducted in 7 patients, by placing side by side the two tubes (microtransducers and perfused catheters) with the sideholes at the same level. The characteristics of the waves were determined both by visual analysis of analog tracing and by semi-automatic analysis of digitized recording with adequate program. Mean amplitude was lower with the microtransducers than with the perfused catheters (60 vs 68 cm H2O; p less than 0.05), but the duration of waves was not significantly different when using both systems. Values obtained for each of these parameters using both methods were significantly correlated (amplitude: r = 0.74; duration: r = 0.51). The localization and the measure of the basal tone of sphincter were found to be difficult when using microtransducers. These results show that PC Polygraf allows a satisfactory analysis of esophageal pressure signals. However, only perfused catheters offer an excellent reliability for complete studies of both sphincter and peristaltism.