Evaluation of a new method for abdominal compression for use in oesophageal investigation.

The use of conventional extra-abdominal compression with a constant cuff pressure was shown to give various pressures intra-abdominally in different subjects. A feedback system was therefore used, in which the extra-abdominal pressure is controlled by the intra-abdominal pressure. For an intra-abdominal pressure increase of 15 mm Hg the external cuff pressure in 20 subjects varied from 21 to 98 mm Hg. There was, however, an almost linear relationship between increased intra-abdominal pressure and cuff pressure. The extra-abdominal pressure required to obtain a certain intra-abdominal pressure also varied with the size of the cuff. To obtain relevant and comparable results in studies of hiatal incompetence and gastro-oesophageal reflux, the feedback system is recommended and the size of the intra-abdominal cuff should be stated.