AJP - GI Track the topics, authors and articles important to you
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Gastrointest Liver Physiol 293: G1023-G1028, 2007. First published September 13, 2007; doi:10.1152/ajpgi.00384.2007
0193-1857/07 $8.00
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
293/5/G1023    most recent
00384.2007v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Web of Science (6)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ghosh, S. K.
Right arrow Articles by Pandolfino, J. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ghosh, S. K.
Right arrow Articles by Pandolfino, J. E.

NEUROREGULATION AND MOTILITY

Utilizing intraluminal pressure differences to predict esophageal bolus flow dynamics

Sudip K. Ghosh, Peter J. Kahrilas, Nilesh Lodhia, and John E. Pandolfino

Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, Illinois

Submitted 17 August 2007 ; accepted in final form 13 September 2007


   ABSTRACT
TOP
 ABSTRACT
MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 
Successful esophageal emptying depends on the generation of a sustained intrabolus pressure (IBP) sufficient to overcome esophagogastric junction (EGJ) obstruction. Our aim was to develop a manometric analysis paradigm that describes the bolus driving pressure difference and the flow permissive time for esophageal bolus transit. Twenty normal subjects were studied with a 36-channel manometry assembly (1-cm spacing) during two 5- and one 10-ml barium swallows and concurrent fluoroscopy. Bolus domain pressure plots were generated by plotting bolus domain pressure (BDP) and EGJ relaxation pressure. BDP was defined as the pressure midway between the peristaltic ramp-up and the proximal margin of the EGJ. The flow permissive time was defined as the period where the BDP was ≥ EGJ relaxation pressure. The mean BDP was 11.7 ± 1.0 mmHg (SE), and the mean flow permissive time was 3.9 ± 0.4 s for 5-ml swallows in normal controls. The mean BDP difference during flow was 4.0 ± 1.0 mmHg. There was no significant difference in the fluoroscopic transit time and the flow permissive time calculated from the BDP plots (5 ml: fluoroscopy 3.4 ± 0.2 s; BDP 3.9 ± 0.4 s, P > 0.05). BDP plots provide a reliable measurement of IBP and its relationship with EGJ relaxation. The time available for flow can be readily delineated from this analysis, and the driving pressure responsible for flow can be accurately described and quantified. This may help predict abnormal bolus transit and the underlying mechanical properties of the EGJ.

esophageal emptying; high-resolution manometry; fluoroscopy; intraluminal pressure gradients

SUCCESSFUL BOLUS TRANSIT DURING swallowing results from a delicate balance between the forces promoting esophageal clearance [peristaltic function and intrabolus pressure (IBP)] and the outflow obstruction at the esophagogastric junction (EGJ) (EGJ compliance) (10). Recent studies combining manometry and intraluminal impedance suggest that abnormal bolus transit is reliant on this delicate balance. Assessing a cohort of 350 patients with dysphagia, Tutuian et al. (11) found that subjects with abnormalities of EGJ relaxation could exhibit normal bolus transit if peristalsis was intact. This finding suggests that normal bolus transit can still occur in the context of a poorly relaxing EGJ if peristalsis can generate a sufficient IBP to overcome the EGJ obstruction pressure. Thus defining the balance between IBP and EGJ obstruction pressure could be helpful in both predicting abnormal bolus transit and defining the dominant mechanism responsible for impaired esophageal emptying.

To quantify the dynamic instantaneous relationship between IBP and EGJ obstruction pressure, it is necessary to measure the intraluminal pressure environment accurately with sufficient resolution of the IBP gradients while also accounting for the dynamic orad movement of the EGJ (7). Conventional manometry with or without a sleeve sensor is not sufficient to accurately measure and resolve the dynamic simultaneous relationship between IBP and EGJ pressure. However, high-resolution manometry (HRM), with a greatly increased number of recording sites and decreased spacing between them, should suffice (5). With HRM, pressure data can be presented in spatial pressure variation plots as a seamless, dynamic representation through the entire esophagus, simultaneously monitoring IBP and EGJ obstruction pressure (measured from EGJ relaxation). Thus the enhanced spatial resolution of HRM may be effectively leveraged to obtain an accurate representation of the intraluminal pressure gradients, while also accounting for the confounding factor of orad motion of the EGJ. The primary goal in this study was to develop a new functional manometric analysis paradigm that describes both the bolus driving pressure and the flow permissive time for bolus transit during swallowing.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 MATERIALS AND METHODS
RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 
Patients. Simultaneous manometric and fluoroscopic studies were done on 20 normal subjects (7 men, ages 20 to 45). Volunteers were recruited by advertisement or word of mouth, had no history of gastrointestinal symptoms or surgery, and were otherwise healthy. The study protocol was approved by the Northwestern University Institutional Review Board, and informed consent was obtained from each subject.

HRM with concurrent fluoroscopy protocol. A solid-state manometric assembly with 36 circumferential sensors spaced at 1-cm intervals (outer diameter 4.2 mm) was used (Sierra Scientific Instruments, Los Angeles, CA). Prior to recording, the transducers were calibrated at 0 and 100 mmHg using externally applied pressure. The response characteristics of the sensing elements exceeded 6,000 mmHg/s with accuracy to within 1 mmHg (8).

After a brief interview and exam, subjects underwent transnasal placement of the manometric assembly. Studies were done in a supine position after at least a 6-h fast, and the manometric assembly was positioned to record from the hypopharynx to the stomach with about three intragastric sensors. The catheter was fixed in place by taping it to the nose. The manometric protocol included a 5-min period to assess basal sphincter pressure and 10 5-ml water swallows. After completion of the manometric protocol, the subjects were placed in the supine position under a C-arm fluoroscope (Easy Diagnostics, Phillips Medical Systems, Shelton, CT) and shielded below the umbilicus with a lead apron. A lead collar was provided for thyroid protection. Fluoroscopic images were recorded using a DVD recorder (LG, RC797T) and were synchronized with manometric data using a video timer (model no. VC 436; Thalner Electronics Laboratories, Ann Arbor, MI) that encodes time in hundredths of a second on each video frame. Two 5-ml and one 10-ml barium swallows were recorded with the potential for a repeat swallow if the first was technically inadequate.

HRM data were subsequently analyzed using both ManoView analysis software (Sierra Scientific Instruments) and custom programs written in Matlab (The MathWorks, Natick, MA). Characterization of the pressure morphology across the esophagus and EGJ was performed with a computer program customized for displaying HRM data as color isocontour plots and spatial pressure variation plots (Fig. 1). This was done by interpolating the space-time pressure signals as described previously (1, 3).


Figure 1
View larger version (64K):
[in this window]
[in a new window]

  		Fig. 1. Isobaric contour (A) and spatial pressure variation (B) representations of a normal swallow. Top: illustrates a representation of the swallow. The color scale of the isobaric contour plot is shown to the right of the plot. Time zero corresponds to the onset of the smooth muscle contraction. B: shows a series of spatial pressure variation plots of the same swallow at 0.5-s intervals. The darkened plot (in gray, 9.5 s) shows the pressure scaling. This method provides a convenient means to visualize intraluminal pressure gradients responsible for esophageal emptying or retrograde escape. The space-time trajectory of the peristaltic amplitude (dashed line), the instantaneous esophagogastric junction (EGJ) relaxation pressure (red circle) and the bolus domain pressure (BDP) at the center of the bolus (green circle located midway between 30 mmHg and the upper margin of the crural diaphragm contraction) are also shown.

 
Measurement of functional manometric parameters. Recognizing that esophageal bolus transport is effected by the balance among the EGJ relaxation pressure, the intraluminal pressure gradients through the EGJ during flow, IBP, and esophageal closure pressure behind the bolus (6), we developed an analysis paradigm that tracked and plotted these as spatial pressure variation plots (Fig. 1B). A surrogate measurement for IBP was created, called the bolus domain pressure (BDP). The BDP was measured and plotted as the pressure midway between the ramp-up or inflexion point of the peristaltic wavefront and the proximal border of the crural component of the EGJ during the swallow (Fig. 1B). This position was chosen to typify pressure within the bolus domain (5). Prior studies have shown that the ramp-up in intraluminal pressure corresponds accurately to the location of the bolus tail (4). This was confirmed by correlating fluoroscopy with the data in spatial pressure variation plots. In addition, previous pilot studies revealed that measuring the IBP at a set position proximal to the EGJ was associated with an artifactual decrease in the time available for bolus transit due to premature intersection with the peristaltic front (3). In instances of either weak or failed peristalsis, a default IBP measurement was performed 2 cm above the proximal border of the EGJ. The BDP was quantified during the smooth muscle contraction, spanning from the transition zone to the point of intersection with the proximal margin of the EGJ. In instances of failed peristalsis, a time period of 10 s beginning at the transition zone was assessed.

The instantaneous EGJ relaxation pressure was defined as the maximum pressure within the EGJ high-pressure zone extending through an ~4-cm span, starting at the proximal margin of the crural diaphragmatic component of the EGJ high-pressure zone. This anatomic zone was chosen because it represents the point of maximal resistance for esophageal emptying (9) (Fig. 1B). All pressures were referenced to atmospheric pressure.

Simultaneous BDP and EGJ relaxation pressure were overlaid to assess the relationship between them during swallows (Fig. 2). Given that the error of pressure measurement was about 1 mmHg, we established a cutoff value of 0 mmHg as the minimal gradient at which flow could potentially occur. For each swallow, the time that the BDP was greater than or equal to the EGJ relaxation pressure was defined as the flow permissive time. In addition, we calculated the mean pressure difference between these two parameters during the flow permissive time.


Figure 2
View larger version (83K):
[in this window]
[in a new window]

  		Fig. 2. Bolus domain pressure analysis for a normal swallow. A: shows a detailed spatial pressure variation plot of distal esophageal peristalsis of the swallow shown in Fig. 1 with a time resolution of 0.2 s. The space-time trajectory of the 30 mmHg isocontour and the BDP measurement location (gray dots) are shown. The location of maximum EGJ relaxation pressure is shown by the black dots. B: shows the BDP analysis, where the instantaneous BDP, EGJ relaxation pressure, and gastric pressure are plotted on the same scale. Periods during which the BDP exceeds maximum EGJ relaxation pressure are deemed flow permissive. The fluoroscopically determined periods of flow are shown by the gray rectangular boxes. C: shows X-ray images of esophageal bolus emptying obtained from concurrent fluoroscopy. Note the hiatal closure at 4.5 s resulting from a crural diaphragm contraction.

 
Relationship between BDP and esophageal emptying. The bolus flow dynamics through the EGJ were analyzed by comparing changes in esophageal emptying rates during 5- and 10-ml swallows. Newton's second law of force balance was used to quantify the approximate mechanical relationship between the intraluminal pressure difference and EGJ opening diameter during trans-sphincteric flow. The mechanical relationship is given by {Delta}P/LH {propto} Q/DH4 where {Delta}P = PBDP – PG is the difference between the bolus domain (PBDP) and gastric (PG) pressures. LH and DH are the length and diameter of the hiatus, respectively, and Q is the esophageal emptying rate (2). The gastric pressure was assumed to be constant for the 5- and 10-ml swallows, and the IBP gradients within the esophagus were assumed to be minimal except at the bolus tail. {Delta}P is approximated as the PBDP – EGJ relaxation pressure. Data for esophageal emptying rate (Q) were obtained from the fluoroscopy study, and LH was assumed to be constant. Sensitivity to changes in EGJ diameter and pressure difference were calculated.

An independent and blinded assessment of transhiatal emptying was made from fluoroscopy and compared with an independent manometric assessment of the time where the pressure difference was permissible for flow. Agreement between fluoroscopy and the flow permissive time was evaluated by plotting these results simultaneously (Fig. 2B).

Statistical analysis. BDP, EGJ relaxation pressure, flow-permissible time, and mean pressure difference between BDP and EGJ relaxation pressure were summarized using mean and standard error. Values for each parameter were compared between 5- and 10-ml swallows using a paired t-test. Agreement between fluoroscopic evidence of bolus transit through the EGJ and flow permissive time was performed by quantifying the overlap of the two time periods.


   RESULTS
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
DISCUSSION
 GRANTS
 REFERENCES
 
BDP: normative values. Nineteen of the 20 normal subjects had complete bolus transit on fluoroscopy for both 5-ml swallows and the single 10-ml swallow and were included in the analysis. One subject had failed peristalsis during the three swallows and was excluded from the analysis. The remaining 19 normal subjects all had intact peristalsis and normal EGJ relaxation during each swallow. The mean peristaltic velocity for the 5-ml swallows was 2.6 cm/s (SE, 0.1) and the mean contractile amplitude for each 5-ml swallow was 128 mmHg (SE, 4). The average lowest residual pressure over a 3-s interval (ManoView eSleeve 3s nadir) for each swallow was 9.4 mmHg (SE, 1.0).

There was no significant difference in the mean BDP during 5-ml and 10-ml swallows in normal subjects (5 ml, 11.7 ± 1.0 mmHg; 10 ml, 11.7 ± 1.3 mmHg; P > 0.05). Simultaneous BDP and EGJ relaxation pressure were plotted and analyzed to determine the time during which the BDP was greater than or equal to the EGJ obstruction pressure (flow permissive time). The mean flow permissive time during the 5-ml swallows was numerically shorter than the flow permissive time during 10-ml swallows; however, this did not reach statistical significance (Table 1). The mean BDP and EGJ relaxation pressure during the flow permissive time were similar during both 5-ml and 10-ml swallows. In addition, there was no significant difference in the bolus driving pressure difference (BDP – EGJ relaxation pressure) during the flow permissive time when 5-ml and 10-ml swallows were compared (Table 1).


View this table:
[in this window]
[in a new window]

  		Table 1. Functional manometric parameters describing the relationship between bolus domain pressure and EGJ relaxation pressure

 
Agreement between fluoroscopy and HRM in predicting bolus transit. There was no significant difference in the flow time calculated from fluoroscopy and the flow permissive time calculated from the BDP plots during 5-ml swallows (fluoroscopy, 3.4 ± 0.2 s; flow permissive time, 3.9 ± 0.4 s, P = 0.13). The flow permissive time was numerically greater than the flow time calculated from fluoroscopy; however, this did not reach statistical significance (fluoroscopy, 3.9 ± 0.4 s; flow permissive time, 5.3 ± 0.5 s, P = 0.09). Fluoroscopically ascertained flow always occurred during the flow permissive time period. In addition, the BDP plots clearly predicted that bolus transit through the EGJ would not occur in the one normal subject with abnormal bolus transit (Fig. 3). In the example in Fig. 3B, the flow permissive time is zero, and this correlates with the fluoroscopic images that show no esophageal emptying during the barium swallow.


Figure 3
View larger version (73K):
[in this window]
[in a new window]

  		Fig. 3. BDP analysis for a swallow with failed peristalsis. A: shows a detailed spatial pressure variation plot with time resolution of 0.4 s. Due to the absence of a continuous propagated 30 mmHg isocontour, the intrabolus pressure (IBP) location was chosen as 2 cm proximal to the upper margin of the EGJ. B: shows the bolus driving pressure analysis, where the instantaneous BDP, EGJ relaxation pressure, and gastric pressure are plotted on the same scale. Periods during which the BDP exceeds maximum EGJ obstruction pressure are deemed flow permissive. Note that there is no manometrically defined flow permissive time for this swallow. C: shows X-ray images of esophageal bolus emptying obtained from concurrent fluoroscopy. No esophageal emptying is observed.

 
EGJ flow dynamics. The esophageal emptying rate calculated from fluoroscopy was significantly greater for the 10-ml swallows compared with 5-ml swallows. However, the bolus driving pressure at the instant of flow initiation (Table 2) and the mean bolus driving pressure during the flow permissive period (Table 1) were statistically similar between 5- and 10-ml swallows. Thus the increased flow rate during 10-ml swallows was not a product of an elevation in the bolus driving pressure gradient and more likely represents a manifestation of increased EGJ opening. The underlying mechanical relationship based on Newton's second law of motion is shown in Fig. 4, where the sensitivity of esophageal emptying rate to changes in bolus driving pressure and EGJ diameter is illustrated. Referencing the sensitivity to the emptying rate of 5 ml (1.7 ml/s; Table 2) at point 0 on the x-axis, one can see that the esophageal emptying rate for a 10-ml bolus (3.1 ml/s; Table 2) may be achieved either by an 82% increase in the bolus driving pressure or a 17% increase in the average EGJ opening diameter.


View this table:
[in this window]
[in a new window]

  		Table 2. Functional analysis of flow dynamics through the EGJ

 

Figure 4
View larger version (10K):
[in this window]
[in a new window]

  		Fig. 4. Sensitivity of esophageal emptying rate to changes in BDP and EGJ diameter. The sensitivity of esophageal emptying rate (trans-sphincteric flow rates) to changes in BDP – EGJ relaxation pressure ({Delta}P) is shown by line A, whereas the sensitivity to changes in EGJ diameter (DH) is shown by line B. Note that all other parameters are held constant when either {Delta}P or DH is varied. All sensitivities are referenced to the emptying of a 5-ml bolus (1.7 ml/s; Table 2). The esophageal emptying rate for a 10-ml bolus (3.1 ml/s; Table 2) may be achieved either by an 82% increase in the bolus driving pressure difference or a 17% increase in the average EGJ opening diameter.

 

   DISCUSSION
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
GRANTS
 REFERENCES
 
Esophageal bolus transit is a carefully coordinated phenomenon in which the mechanical balance between the peristaltic closure pressure, the IBP, and the EGJ relaxation pressure determines the effectiveness of esophageal emptying. Despite the importance of this delicate balance, there has been very little focus on measuring the relationship between IBP and EGJ relaxation pressure during the clinical manometric assessment of swallowing. This lack of information does not represent a lack of interest but more likely a lack of precision in conventional manometric equipment to accurately measure the dynamic variations in IBP. Previous work utilizing combined HRM and fluoroscopy at the upper esophageal sphincter provided important information regarding the sensitivity of IBP gradients to pathological sphincter constriction (7). The goal of the present study was to apply a similar analysis method to the distal esophagus to devise a new paradigm that assesses bolus transit across the EGJ. Our results suggest that HRM may be adapted to provide a reliable measurement of IBP and its relationship with EGJ relaxation pressure. In addition, this paradigm can quantify a flow permissive time interval based on intraluminal pressure gradients and may also provide important information regarding flow dynamics through the EGJ.

The notion that the measurement of IBP should be included in the evaluation of bolus transit is not new. Previous work from Ren et al. (10) utilizing combined conventional manometry and fluoroscopy demonstrated the mechanistic relationship between effective esophageal transport and the difference between intraluminal closure pressure of the peristaltic wavefront and the baseline IBP. Their findings suggested that an intraluminal peristaltic closure pressure at least 20 mmHg greater than IBP was invariably associated with effective bolus transit, whereas pressures below this threshold could be associated with impaired transit. Our analysis differed from this previous work in that we focused our interest on the relationship between the BDP distal to the closure wave and its simultaneous relationship to EGJ relaxation pressure to assess bolus transit dynamics. Our analysis plotted the instantaneous BDP and EGJ relaxation pressure to define periods of the time during which flow could potentially occur based on preferential gradients. We found that the mean flow permissive time determined by manometry was similar to the mean time during which there was fluoroscopic evidence of flow. In addition, esophageal emptying during fluoroscopy always occurred during the flow permissive time defined by the BDP plots.

Although fluoroscopic esophageal emptying only occurred during the flow permissive time period, the flow permissive time was always slightly greater than the actual time where flow was documented on fluoroscopy. This slight overestimation of flow time by the bolus driving pressure plots likely represents some of the limitations of determining bolus transit using preferential intraluminal pressure differences. Although it is possible that flow is not occurring despite a preferential gradient due to mechanical properties of the EGJ, it is more likely that our accuracy of ±1 mmHg and our cutoff value for a preferential flow of an IBP ≥ EGJ relaxation pressure may be too liberal. We suspect that this threshold value likely overestimated flow time; however, this overestimation was small and would probably not alter the overall prediction of normal bolus transit in a given individual.

The mechanism underlying significantly different esophageal emptying rate between the 5-ml and 10-ml swallows (Table 2) may be explained by one or a combination of two possible mechanical consequences: 1) gastric pressure being relatively constant, the upstream pressure within the esophagus must increase to sustain an elevated esophageal emptying rate for the 10-ml swallows, resulting in an altered intraluminal pressure dynamic; or 2) a proportional increase in the hiatal radius is necessary to maintain the same level of IBP while elevating the emptying rate. However, as shown in Fig. 4, the dominant mechanism is likely one of increased hiatal diameter that enables complete esophageal emptying of higher volume bolus in normal subjects. Thus when the analysis paradigm presented here is combined with a mechanistic analysis based on Newton's laws, it may be possible to quantify the underlying mechanical parameters that result in impaired esophageal emptying. This, however, would require information on esophageal emptying rate using concurrent fluoroscopy or, potentially, impedance. Furthermore, a confounding factor in the difference between the two volumes may be that salivary and luminal secretions potentially alter the effective swallow volume and the resultant measure of esophageal emptying rate.

In conclusion, we have developed a novel paradigm for assessing the instantaneous relationship between the BDP and the primary outflow obstruction pressure at the EGJ (relaxation pressure) during a swallow using HRM. The time available for flow can be readily delineated from this analysis, and the pressure gradients responsible for flow can be accurately described and quantified. Although this manometric paradigm does provide significant functional information regarding esophageal emptying through the EGJ, further validation is required to determine its predictive value for bolus transit and also whether it can be combined with impedance to determine EGJ opening dynamics.


   GRANTS
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 GRANTS
REFERENCES
 
This work was supported by K23 DK062170-01 (J. E. Pandolfino) and RO1 DC00646 (P. J. Kahrilas) from the Public Health Service.


   FOOTNOTES
 

Address for reprint requests and other correspondence: J. E. Pandolfino, Northwestern Univ., Feinberg School of Medicine, Div. of Gastroenterology, Dept. of Medicine, 676 N. St. Clair St. Suite 1400, Chicago, Illinois 60611 (e-mail: j-pandolfino{at}northwestern.edu)

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.


   REFERENCES
TOP
 ABSTRACT
 MATERIALS AND METHODS
 RESULTS
 DISCUSSION
 GRANTS
 REFERENCES
 

  1. Clouse RE, Staiano A. Topography of the esophageal peristaltic pressure wave. Am J Physiol Gastrointest Liver Physiol 261: G677–G684, 1991.[Abstract/Free Full Text]
  2. Ghosh SK, Kahrilas PJ, Zaki T, Pandolfino JE, Joehl RJ, Brasseur JG. The mechanical basis of impaired esophageal emptying post fundoplication. Am J Physiol Gastrointest Liver Physiol 289: G21–G35, 2005.[Abstract/Free Full Text]
  3. Ghosh SK, Pandolfino JE, Zhang Q, Jarosz A, Shah N, Kahrilas PJ. Quantifying esophageal peristalsis with high-resolution manometry: a study of 75 asymptomatic volunteers. Am J Physiol Gastrointest Liver Physiol 290: G988–G997, 2006.[Abstract/Free Full Text]
  4. Kahrilas PJ, Dodds WJ, Hogan WJ. Effect of peristaltic dysfunction on esophageal volume clearance. Gastroenterology 94: 73–80, 1988.[Web of Science][Medline]
  5. Li M, Brasseur JG, Dodds WJ. Analyses of normal and abnormal esophageal transport using computer simulations. Am J Physiol Gastrointest Liver Physiol 266: G525–G543, 1994.[Abstract/Free Full Text]
  6. Massey BT, Dodds WJ, Hogan WJ, Brasseur JG, Helm JF. Abnormal esophageal motility. An analysis of concurrent radiographic and manometric findings. Gastroenterology 101: 344–354, 1991.[Web of Science][Medline]
  7. Pal A, Williams RB, Cook IJ, Brasseur JG. Intrabolus pressure gradient identifies pathological constriction in the upper esophageal sphincter during flow. Am J Physiol Gastrointest Liver Physiol 285: G1037–G1048, 2003.[Abstract/Free Full Text]
  8. Pandolfino JE, El-Serag HB, Zhang Q, Shah N, Ghosh SK, Kahrilas PJ. Obesity: a challenge to esophagogastric junction integrity. Gastroenterology 130: 639–649, 2006.[CrossRef][Web of Science][Medline]
  9. Pandolfino JE, Shi G, Curry J, Joehl RJ, Brasseur JG, Kahrilas PJ. Esophagogastric junction distensibility: a factor contributing to sphincter incompetence. Am J Physiol Gastrointest Liver Physiol 282: G1052–G1058, 2002.[Abstract/Free Full Text]
  10. Ren J, Massey BT, Dodds WJ, Kern MK, Brasseur JG, Shaker R, Harrington SS, Hogan WJ, Arndorfer RC. Determinants of intrabolus pressure during esophageal peristaltic bolus transport. Am J Physiol Gastrointest Liver Physiol 264: G407–G413, 1993.[Abstract/Free Full Text]
  11. Tutuian R, Castell DO. Combined multichannel intraluminal impedance and manometry clarifies esophageal function abnormalities: study in 350 patients. Am J Gastroenterol 99: 1011–1019, 2004.[CrossRef][Web of Science][Medline]




This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
293/5/G1023    most recent
00384.2007v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Web of Science (6)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ghosh, S. K.
Right arrow Articles by Pandolfino, J. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ghosh, S. K.
Right arrow Articles by Pandolfino, J. E.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2007 by the American Physiological Society.