Comparison of lower oesophageal sphincter pressure measurement using circumferential vs unidirectional transducers

Average values from unidirectional (UND) transducers have traditionally been used in standard manometric evaluation of lower oesophageal sphincter pressures (LOSPs). A single circumferential (CMF) transducer has recently become popular. Our aim was to compare LOSP measurements made using the two techniques. Ten healthy volunteers were intubated with a Konigsberg manometry catheter containing five solid-state transducers (four unidirectional at 90 degrees angles radially and 2.5-cm intervals and one circumferential, 3 cm distal). LOSP was measured using the station pull-through technique in the supine and upright positions with Synectics Polygram software for computerized analysis. Mean UND pressures were plotted against CMF pressures and a linear regression and correlation analysis was performed. A similar analysis was done for LOS length. A significant difference (P < 0.01) was found between mean (+/- SE) supine and upright LOSPs for both mean UND (20.21 +/- 1.36 vs 15.56 +/- 1.28 mmHg) and CMF (20.41 +/- 1.96 vs 16.17 +/- 1.61 mmHg); however no difference was shown between supine and upright lengths. There was a high degree of correlation between LOSP (r = 0.83) and a weaker correlation (r = 0.65) between LOS lengths when measured by CMF and UND transducers.

UND and CMF transducers provide identical measurements when evaluating the LOS.