Technological insights: Combined impedance manometry for esophageal motility testing-current results and further implications

Figure 4 The 2 recently available systems of combined impedance manometry. During esophageal motility testing the most distaly located pressure transducer was positioned at the lower esophageal high pressure zone. Left panel: 15 channel catheter for combined impedance-manometry procedure. The 4 semiconductor solid-state pressure transducers (P1-P4) serve also as impedance electrodes and are placed at 6 cm distance each. There are 11 impedance segments, each 2 cm long (Ch1-Ch11) with a cascade configuration. The solid-state pressure transducers (P1-P4) are located exactly between the impedance channels 1-2, 4-5, 7-8 and 10-11, respectively. Right panel: 9-channel esophageal function testing catheter with five pressure sensors and four impedance-measuring segment. The impedance measuring-segments consist of pairs of metal rings placed 2 cm apart, centered at 10, 15, 20 and 25 cm from the tip (Z1-Z4). Four of five the pressure sensors are located within the impedance segments (P1-P4). The 5^th pressure sensors (P5) is located 5 cm from the tip.