Submitted on August 17, 2007
Accepted on September 13, 2007
Utilizing Intraluminal Pressure Differences to Predict Esophageal Bolus Flow Dynamics
Sudip Kumar Ghosh1, Peter J. Kahrilas2, Nilesh Lodhia2, and John E Pandolfino3*
1 Department of Medicine, Northwestern University, Chicago, Illinois, United States
2 Division of Gastroenterology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, United States
3 Gastroenterology, Northwestern University, Chicago, Illinois, United States
* To whom correspondence should be addressed. E-mail: j-pandolfino{at}northwestern.edu.
Background: Successful esophageal emptying depends on the generation of a sustained intrabolus pressure (IBP) sufficient to overcome 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.
Methods: 20 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.
Results: 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 (5ml: fluoroscopy 3.4 s ± 0.2 s; BDP 3.9 ± 0.4 s, p>0.05).
Conclusions: BDP plots provide a reliable measurement of intrabolus pressure (BDP) 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.
