[Monitoring esophageal pressure: comparison of various methods and a unique solution]

Ambulatory monitoring of intraesophageal pressure requires probes and techniques which are different from those used in the laboratory approach. In particular the perfusion system for the measurement of the pressure is not suitable and the development of alternative solutions is mandatory. In this perspective an accurate analysis of the theoretical basis of different methods is necessary in order to avoid incorrect results and difficulties in the subsequent phase of analysis. A prototype probe, which is based on inextensible thin plastic balloons filled with oil or saline, was tested in comparison with traditional (perfused) and microtransducer systems to outline the positive and negative aspects of the solution. The results were satisfactory as regards linear output and frequency response up to 5 Hz for the prototype probe and even superior, for instance, to the response of the perfused system to applied pressure, whose curves of the four open tips resulted different, and to the response of Millar transducer. The new prototype probe seems to be adequate to the clinical and research needs.