Quantitation of pharyngeal motor function in normal human subjects.

A need exists for accurate pressure recording of pharyngeal motor events. Results of this study indicate that accurate quantitation of pharyngeal motor activity is not possible using a water-filled catheter system, even when high infusion rates are used. An intraluminal strain gauge system, however, achieves high-fidelity recording. Quantitation of pharyngeal peristalsis using the intraluminal strain gauge system reveals peristaltic pressure amplitudes higher than those hitherto recorded. In normal subjects, peristaltic amplitude averages about 200 mmHg in the hypopharynx, complexes in one subject being as high as 600 mmHg. A zone of relatively low pressure exists in the oropharynx. Mean pharyngeal wave duration decreases progressively in an aboral direction, from 1.0 to 0.3 s, and peristaltic wave speeds range between 9 and 25 cm/s. Accurate quantitation of pharyngeal peristaltic variables provides the necessary basis for characterization and assessment of pharyngeal motor disorders.

The effect of manometric assembly diameter on intraluminal esophageal pressure recording.

Recent studies indicate that lower esophageal sphincter pressure is influenced by manometric assembly diameter. This study determines the effect of assembly diameter on both esophageal sphincter pressure and peristaltic pressure in the esophageal body. We performed esophageal manometric studies in 6 normal subjects using graded assembly diameters. High-fidelity recording was achieved by using a noncompliant catheter-infusion system. The results indicate that increases in assembly diameter cause significant increases in peristaltic pressure amplitudes and in resting sphincter pressure in both the smooth and striated muscle portions of the esophagus. This phenomenon is best explained by the length-tension characteristics of esophageal muscle, increased stretch causing greater contraction force.

Effect of increased intraabdominal pressure on lower esophageal sphincter pressure.

This study evaluates the effect of intraabdominal pressure increases on lower esophageal sphincter (LES) pressure in normal subjects and in patients with reflux esophagitis. Intraabdominal and intragastric pressure were increased by abdominal compression, the Valsalva maneuver, and leg raising. In normal subjects changes in pressure recorded from the LES equaled the changes in gastric pressure induced by abdominal compression and Valsalva. Consquently the LES-gastric pressure gradient remained unchanged. During leg raising, pressure recorded from the LES increased more than gastric pressure, thereby increasing the LES-gastric pressure gradient. Although statistically significant, the LES pressure increases associated with leg raising were modest, unrelated to initial sphincter pressure, and unaffected by atropine. When individuals demonstrating a "common cavity" phenomenon were exculed, LES pressure changes during abdominal compression were similar in patients with esophagitis and in normal volunteers. Consequently, response of the LES to abdominal compression generally does not separate patients with esophagitis from normal subjects. We believe that the LES responses to increased intra-abdominal pressure observed in this study are better accounted for by mechanical factors than by a physiologic adaptive response of intrinsic LES tone.

A rapid pull-through technique for measuring lower esophageal sphincter pressure.

Because disadvantages are inherent in the conventional station pull-through technique (SPT) currently used for recording lower esophageal sphincter pressure (LESP), a more suitable recording method is needed. In study, we evaluated a rapid pull-through technique (RPT) for recording LESP and compared the results with those obtained by SPT. The RPT features rapid withdrawal of recording sensors across the LES during a 10- to 20-sec interval of suspended respiration. This method avoids recording "artifact" caused by respiratory LES motion and provides precise end points for scoring and measurement. In 12 normal subjects, LESP measured by RPT (24.3 plus or minus 0.5 mm Hg) was comparable, but significantly greater, than LESP measured by SPT (21.1 plus or minus 9.1 mm Hg). Analysis of LESP scores for the two recording methods revealed that both intraobserver and interobserver error were substantially less for RPT than SPT (P less than or equal to 0.01). Further correlation of LESP between studies was greater for the RPT than the SPT recording method. We conclude that RPT represents a convenient method for recording LESP which is easier to perform and yields more reproducible values than LESP recording by SPT.