Dynamics of esophageal bolus transport in healthy subjects studied using multiple intraluminal impedancometry

Abstract

The dynamics of a bolus transport through the esophagus are largely unexplored. To study this physiological process, we applied multiple intraluminal impedancometry in 10 healthy subjects. Three different protocols were used: 1) liquid bolus administered with subject supine, 2) liquid bolus with subject upright, or 3) semisolid bolus with subject supine. Transit of different parts of a bolus (bolus head, body, and tail) was analyzed at different anatomic segments, namely the pharynx and the proximal, middle, and distal thirds of the esophagus. A characteristic pattern of bolus transport was seen in all subjects. Impedance changes related to air were observed preceding the bolus head. The bolus head propelled significantly faster than did the bolus body and tail. Pharyngeal bolus transit was significantly faster than esophageal bolus transit. Within the esophagus, bolus propulsion velocity gradually decreased. Bolus transport was significantly accelerated in the upright position and delayed with increase of bolus viscosity. In conclusion, the dynamics of a bolus transport from the pharynx into the stomach are complex. It varies within both different anatomic segments and different parts of the bolus and depends on bolus characteristics and test conditions. The spatial and temporal resolution of a bolus transport can be obtained by the impedance technique.

Review article: intra‐oesophageal impedance monitoring for the assessment of bolus transit and gastro‐oesophageal reflux

“…3 Transit time and propagation velocity of a bolus were faster in upright position and decreased with increasing bolus viscosity. Fluoroscopy was used to validate impedance monitoring as a means to study volume clearance in healthy subjects.…”

“…2 Passage of a swallowed bolus along a neighbouring pair of electrodes yields a typical impedance tracing, including five phases ( Figure 2): baseline impedance during resting stage of the oesophagus (phase 1); impedance rise caused by arrival and passage of a small amount of air ahead of the bolus (phase 2); impedance drop and recovery caused by arrival and passage of the bolus (phase 3); impedance rise caused by rapid wall contraction associated with lumen occlusion (phase 4) and recovery of impedance signal to baseline level during transition to resting stage (phase 5). 3 Multichannel oesophageal monitoring can be carried out by using an intraluminal catheter with multiple, closely spaced pairs of metal rings. Changes in spatiotemporal patterns in impedance are identified at various levels within the oesophagus, allowing differentiation between antegrade (swallow) and retrograde (reflux) bolus movement 4 ( Figure 3).…”

“…2,3,[5][6][7][8][9][10][11][12] Figure 2. Bolus passage along a neighbouring pair of electrodes yields a typical impedance tracing, including five phases: baseline impedance during resting stage of the oesophagus (phase 1); impedance rise caused by arrival and passage of an air volume ahead of the bolus (phase 2); impedance drop and recovery caused by arrival and passage of the bolus (phase 3); impedance rise caused by wall contraction associated with lumen occlusion (phase 4) and recovery of impedance signal to baseline level during transition to resting stage (phase 5).…”

Study of intestinal flow by combined videofluoroscopy, manometry, and multiple intraluminal impedance

“…multichannel intraluminal impedance; manometry; fluoroscopy; intestinal motility MULTIPLE INTRALUMINAL IMPEDANCE (MII) is a novel technique that can detect flow in a viscous organ by measuring changes in intraluminal impedance related to the movement of the bolus (24). MII was recently used for measuring bolus transport in the esophagus in health and disease states (12,23,21). The technique is capable of distinguishing between refluxate containing air or liquid (22) and can recognize nonacid reflux, currently undetected by pH monitoring (5).…”

“…MII was recently used for measuring bolus transport in the esophagus in health and disease states (12,23,21). The technique is capable of distinguishing between refluxate containing air or liquid (22) and can recognize nonacid reflux, currently undetected by pH monitoring (5).…”