Truncal vagotomy as a possible potentiator of gastric atony

To simulate ulcer patients undergoing operation for gastric outlet stenosis, pyloric obstruction was created in dogs and repaired with pyloroplasty to which was added truncal vagotomy, proximal gastric vagotomy, or no vagotomy. Gastric antral contractile activity after feeding a solid meal was studied before and after repair (2 week period of study). This activity was correlated with the initial lag and regulated phases of solid meal emptying. Five quantified indices of contractile activity measured during the first postprandial hour indicated variable and inconclusive results in the antrum during the lag phase (first 20 minutes). Consistent percentage changes in these indices after obstruction repair were seen during the subsequent regulated phase. Gastric work was reduced 28 to 35 percent, but not work capability (mean area), by pyloric obstruction in the no vagotomy dogs. Reductions seen in proximal gastric vagotomy dogs were not different from those in the no vagotomy dogs. Higher percentages of reduction in amplitude (70 percent) and mean area of contractions (53 percent) occurred after truncal vagotomy compared with what occurred in the no vagotomy dogs. Mean area was also reduced more compared with what occurred in the proximal gastric vagotomy dogs. These data indicate that the reduced gastric work after feeding and impaired work capability caused by truncal vagotomy when superimposed on that produced by pyloric obstruction may exaggerate gastric atony and contribute to the delayed recovery of gastric emptying seen in the clinical setting.