Mo2107 Vagal Activation and Changes in Peptidergic Neurotransmission With Vasoactive Intestinal Polypeptide and Substance P During Postoperative Ileus in Rat

Abstract

Listen

Translate article

Introduction: Simultaneous manometry and intraluminal ultrasound imaging studies show that similar to contraction wave, distension wave traversing ahead of contraction wave is also peristaltic. Cross sectional area (CSA) of the esophagus is one of the several variables that determine intraluminal esophageal impedance value. Aim: We recorded simultaneous intraluminal US images, impedance and high resolutionmanometry to determine the relationship between esophageal CSA and intraluminal esophageal impedance values. Studies were conducted in 15 normal healthy subjects. Impedance and manometry were measured along the whole length of the esophagus (Sierra Scientific) and US images were recorded at 2 and 12 cm above the LES. Swallow induced primary peristalsis was recorded using 5 ml bolus of 0.5 N saline. Impedance data were exported to Excel and analyzed for the baseline and lowest impedance value at each level. Cross sectional area of the esophagus at 4 and 14 cm of the esophagus were measured from the US images. Results: Impedance recordings show that following a swallow, the onset of drop in impedance as well as nadir impedance traverses the esophagus in a sequential fashion in front of the contraction wave (figure, left panel). There is strong linear relationship between the location and nadir impedance value such that the lowest impedance values are located just above the LES, with a difference of approximately 100 ohms every 1 cm along the length of the esophagus (right panel). Atropine injected intravenously (10 μgm/kg) abolished esophageal contractions, reduced baseline esophageal impedance and abolished sequential progression of nadir impedance along the esophagus). US image analysis shows that peak distension corresponds with nadir impedance value. Similar to nadir impedance, peak distension recorded by US imaging traverses the esophagus in a peristaltic fashion. US images show greater esophageal distension at 4 cm compared to 14 cm above the LES, cross sectional area of 1400 versus 600 mm2 respectively. Conclusion: These data prove: 1) intraluminal distension and contraction wave during peristalsis are tightly linked and 2) intraluminal impedance recording is a relatively simple technique to record luminal distension of the esophagus.