This study
aimed to develop and validate a method to measure bolus flow time
(BFT) through the esophagogastric junction (EGJ) using a highresolution
impedance-manometry (HRIM) sleeve. Ten healthy subjects
were studied with concurrent HRIM and videofluoroscopy;
another 15 controls were studied with HRIM alone. HRIM studies
were performed using a 4.2-mm-outer diameter assembly with 36
pressure sensors at 1-cm intervals and 18 impedance segments at 2-cm
intervals (Given Imaging, Los Angeles, CA). HRIM and fluoroscopic
data from four barium swallows, two in the supine and two in the
upright position, were analyzed to create a customized MATLAB
program to calculate BFT using a HRIM sleeve comprising three
sensors positioned at the crural diaphragm. Bolus transit through the
EGJ measured during blinded review of fluoroscopy was almost
identical to BFT calculated with the HRIM sleeve, with the nadir
impedance deflection point used as the signature of bolus presence.
Good correlation existed between videofluoroscopy for measurement
of upper sphincter relaxation to beginning of flow [R  0.97, P 
0.001 (supine) and R  0.77, P  0.01 (upright)] and time to end of
flow [R  0.95, P  0.001 (supine) and R  0.82, P  0.01
(upright)]. The medians and interquartile ranges (IQR) of flow time
though the EGJ in 15 healthy subjects calculated using the virtual
sleeve were 3.5 s (IQR 2.3–3.9 s) in the supine position and 3.2 s (IQR
2.3–3.6 s) in the upright position. BFT is a new metric that provides
important information about bolus transit through the EGJ. An assessment
of BFT will determine when the EGJ is open and will also
provide a useful method to accurately assess trans-EGJ pressure
gradients during flow.