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Following are current pier-reviewed publications involving the use of ManoScan. We welcome any literature relating to high resolution manometry and will post selected articles subject to SSI review and clearance from the author(s).

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High-Resolution Manometry (HRM) Reveals Bolus Entrapment in the Proximal Esophagus with Double Swallows in Patients with Spastic Motor Disorders

Clinton T. Snedegar, M.D., Laura R. Haroian, MSN, and Ray E. Clouse, M.D.

A system for HRM has been developed that uses a catheter with 36 solid-state pressure sensors spaced at 1-cm intervals and spans the entire esophagus (Sierra Scientific Instr., Los Angeles). Deglutitive inhibition (DI) was examined with this system by evaluating the effects of repetitive wet swallows. Methods: 7 subjects undergoing clinical manometry and having normal findings and 9 subjects with spastic disorders (2 DES, 7 nonspecific) agreed to undergo HRM manometry. A series of paired wet swallows was offered, with the 2nd swallow spaced at <3s, >3-<5s, >5-<7s, or >7s from the 1st. Data were analyzed from contour maps created for each pair. Results: 134 paired swallows were available for analysis, and the effects of DI were easily visualized on the maps. Swallows spaced by <3s completely inhibited further transmission of peristalsis if contraction in the smooth-muscle segments had not begun. Pairs with greater inter-swallow delay showed variable degrees of distal inhibition, and a distinctive difference between subject groups could not be determined. A striking finding of isobaric pressure increase with the 2nd swallow was noted in some subjects consistent with bolus entrapment above ongoing distal motor activity from the 1st swallow (figure). Systematic measurement of peak and 2-s mean intrabolus pressure 4 and 8 cm below the UES following the 2nd swallow revealed significantly (p<0.05) increased pressures in the spastic disorder subjects in swallows paired at <3s or >5-<7s and trend toward increases when paired at >7s (p<0.1). Explanations for entrapment varied and included ongoing prolonged distal contraction of the 1st swallow and impaired inhibition as the 1st wave continued toward the LES. Conclusions: HRM demonstrates DI in a novel way using contour maps to show inhibition of the peristaltic sequence. Proximal bolus entrapment during repetitive swallows, in part from impaired DI, may serve as a stimulus for dysphagia and chest pain in patients with spastic disorders.

Citation:
Snedegar CT, Haroian LR, Clouse RE. High-resolution manometry (HRM) reveals bolus entrapment in the proximal esophagus with double swallows in patients with spastic motor disorders. Gastroenterology, 2004; in press.

Creation of an Electronic Sleeve Emulation (eSleeve) for Use with Solid-State High-Resolution Manometry (HRM)

Ray E. Clouse, Thomas R. Parks, Annamaria Staiano, Laura R. Haroian

Sleeve devices have advantages in measuring sphincter pressures and relaxation because they account for axial movement of the sphincter and barrier pressure location. A sleeve was emulated electronically for use with HRM. Methods: 32 pts underwent HRM using 36 solid-state circumferential sensors spaced at 1-cm intervals (Sierra Scientific Instr). LES basal pressure (BP) was measured for 30s at each of 4 locations to determine if offset in sensor placement by 5-mm influenced findings; LES residual pressure (RP) also was measured with wet swallows in 2 catheter locations having 5-mm sensor offset. 6 sensors spanning the LES were used to emulate a 5-cm sleeve; a sensor 2 cm distally measured concurrent intragastric pressure. Pressures were interpolated across sensors to visualize eSleeve findings (Fig a: 3D map of LES relaxation). Maximum pressure along the 5-cm sleeve is represented by the skyline view of the map (Fig c). Results: Absolute difference in expiratory (exp) BP with 5-mm sensor offset was low and less than inspiratory variation (2.5+0.4 vs 5.1+1.1; p<0.05); 5-mm offset produced less variation in exp BP than was seen with repeat measurement at same site (p<0.05). Agreement in BP dx (low/normal/high) between original and offset location occurred in 14/15 pts with abnormal BP (overall agreement: 31/32 or 96.9%). 9 pts had abnormal mean RP (>5 mm Hg for the <5s nadir); agreement in dx was complete for the 2 catheter positions. Conclusions: The eSleeve is a novel way of measuring sphincter pressure that incorporates perfused sleeve advantages while using solid-state technology. Sensor position had little impact on findings indicating that post hoc selection of eSleeve location during HRM data review is feasible. These methods should improve diagnostic accuracy of HRM without adding technical requirements.

Citation:
Clouse RE, Parks TR, Staiano A, Haroian LR. Creation of an electronic sleeve emulation (eSleeve) for use with solid-state high-resolution manometry (HRM). Gastroenterology, 2004; in press.

Figure: Sleeve emulation using high-resolution manometry methods. The recording catheter employed 36 circumferential solid-state sensors spaced at 1-cm intervals. a) A contour map of a single swallow with recording sites spanning the region from the pharynx to the stomach. The rectangle outlines the 5-cm region used for electronic sleeve (�E-sleeve�) measurements over the 10-second period following the swallow. b) A surface or wiremesh map of the sleeve recording pressures shows sphincter relaxation in a three-dimensional view. c) The surface map is viewed from the gastric perspective with values corrected for concurrently measured intragastric pressure. The upper curve of this map reflects the sleeve measurement of sphincter relaxation, revealing the maximum pressure along the length of the sleeve at all times. Residual pressure can be calculated from this curve. Adapted from: Clouse RE, Staiano A, Parks T. Creation of sleeve emulations from high-resolution manometry using perfused (�P-sleeve�) or electronic (�E-sleeve�) sensors. Gastroenterology 2004 abstract (submitted to DDW)

Novel Solid-State Technology Simplifies High-Resolution Manometry (HRM) for Clinical Use

Ray E. Clouse, M.D., Thomas R. Parks, Ph.D., Laura R. Haroian, MSN

HRM offers advantages over conventional methods in both research and clinical studies of esophageal motility. Widespread use of HRM has been limited by technical complexity of water-perfusion required for systems with large numbers of closely-spaced pressure recording sites. Re-positioning of the catheter is required to completely sample the esophagus and sphincters with equivalent high resolution. For this report, a solid-state system was developed and tested in a clinical population. Methods: 42 subjects (age 15-84 yr; 28 female) were recruited from patients referred for clinical manometry. Each underwent HRM with a system developed specifically for solid-state HRM (Manoscan; Sierra Scientific Instr, Los Angeles). A 4.2 mm OD catheter containing 36 solid-state sensors spaced at 1-cm intervals was positioned so that 1-2 sensors were proximal to the upper esophageal sphincter (UES). Sphincter locations were determined by viewing contour maps of HRM data. Lower esophageal sphincter (LES) basal pressure was determined during slow respiration from an intrasphincteric location before 10 wet swallows were offered. The catheter was withdrawn so that the sensors were offset 5 mm from the original position and wet swallows were repeated. Diagnoses were established at each position using a combination of conventional parameters (taken from locations easily determined from contour-map review) and subjective evaluation of the maps. Categorical diagnoses were established using previously reported methods. Results: 10 subjects had completely normal findings. Of those with abnormalities, 7 had hypomotility features, 21 hypermotility (14 non-specific spastic disorders, 3 DES, 4 achalasia), and 4 had mixed features. Diagnoses did not differ within subjects when analyses were performed at each of the 2 catheter positions. Subjective interpretation of the maps was simplified by the fact that the UES, entire esophagus, and LES were included on individual maps of each swallow, and features previously described when using HRM for interpretation of motor disorders were easily identified. Conclusions: HRM using the Manoscan, a novel solid-state system, eliminates water perfusion and simplifies the technical aspects of this manometric technique. Catheter position (with regard to 5 mm sensor offset) did not influence diagnosis � further reducing technical demands at the time of the study and allowing post-hoc sensor selection for analysis. This approach should increase the acceptability of HRM for clinical use.

This work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases (Grant R44 DK056539-03)

Citation:
Clouse RE, Parks TR, Haroian LR. Novel solid-state technology simplifies high-resolution manometry (HRM) for clinical use. Gastroenterology, 2004; in press.

DEVELOPMENT AND CLINICAL VALIDATION OF A SOLID-STATE HIGH-RESOLUTION PRESSURE MEASUREMENT SYSTEM FOR SIMPLIFIED AND CONSISTENT ESOPHAGEAL MANOMETRY

Ray E. Clouse, MD, Thomas Parks, PhD, Laura R. Haroian, MSN, Salam F. Zakko, M.D.

Division of Gastroenterology, Washington University School of Medicine, St. Louis, MO, Sierra Scientific Instruments, Los Angeles, CA, and Division of Gastroenterology, University of Connecticut School of Medicine, Farmington, CT

Previous work has shown that high-resolution esophageal manometry using closely spaced sensors and 3D data displays improves diagnostic accuracy and simplifies landmark identification. However, complexity of water-perfused devices required to conduct such studies and limitation in number of pressure channels have restricted its utility and widespread use. Aims: 1) To develop a solid-state system that spans the entire esophagus and capitalizes on the advantages of high-resolution manometry; and 2) to compare its performance with a commercially available system in human subjects. Methods: A solid-state high-resolution system (ManoScan, Sierra Scientific Instr, Los Angeles) was developed employing a 4.2 mm soft, molded catheter and 36 circumferential sensors based on patented pressure sensing technology. The sensors, spaced at 1-cm intervals, use high speed processing that routes pressure data to a computerized display allowing real-time monitoring and post-study review of topographic contour plots. To minimize the impact on learned physician practices in manometric interpretation, display software was designed to permit simultaneous visualization of conventional tracings by rapid selection of measurement points at pre-set levels in relationship to the topographically identified sphincters. For initial clinical validation of the methods, 20 subjects agreed to undergo a repeat manometric study using the HRS after completing clinical manometry with a commercially available 21-channel water-perfused system with existing topographic display that requires 2 catheter positions for complete sampling (MMS, Dover NH). Diagnoses were compared after independent analysis. Results: The HRS real-time contour plots allowed rapid initial positioning of the catheter such that recording sensors spanned the pharynx to the stomach in each case. 15 subjects (75%) had motor disorders (achalasia, spastic disorders, hypomotility), all diagnostic information being gained from a single set of 10 swallows at one catheter position. Crural indentations were easily identified, as were hiatal hernias in 6 subjects. Final diagnoses did not differ between methods. Conclusions: The solid-state HRS reduces procedure time and simplifies esophageal manometry while providing high-resolution data from the entire esophagus for accurate diagnosis. These innovations afford an important step toward consistency in this clinical test of motor function.

His work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases (Grant R44 DK056539-03)

Citation:
Clouse RE, Parks T, Haroian LR, Zakko SF. Development and clinical validation of a solid-state high-resolution pressure measurement system for simplified and consistent esophageal manometry. Am J Gastroenterol, 2003;98(Suppl):S32-S33.