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

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