Metabolic acidosis and respiratory acidosis impair gastro-pyloric motilityin anesthetized rigs

Acidosis impairs smooth muscle function in various organs. However, the eff ects of acidosis on the gastroduodenal tract are unknown while its dysfunct ion has potential perioperative harmful consequences. We investigated the e ffects of metabolic (MA) and respiratory acidosis (RA) on upper gut motilit y in tracheally ventilated pigs whose anesthesia was induced with halothane and maintained with alpha-chloralose-urethane administration (IV). Increas ed dead space and perfusion of hydrochloric acid 1 N (150 mL over 30 min) w ere used to induce RA and MA, respectively. Measurements of fundic tone usi ng an electronic barostat, antro-pyloroduodenal phasic motility with perfus ed manometry and antro-duodenal electric control activity by electromyograp hy were used to evaluate gastroduodenal function. Acidosis increased the fu ndic tone as reflected by a decrease in barostat volumes from 275 +/- 83 to 194 +/- 88 mL for MA and from 278 +/- 93 to 236 +/- 106 mL for RA. Pyloric and duodenal basal tones were not affected by either acidosis. A decrease in pyloric contraction amplitude from 95 +/- 24 to 62 +/- 26 mm Hg during M A and from 94 +/- 26 to 64 +/- 20 mm Hg during RA was observed. Both acidos is altered antral control activity that became dysrhythmic. Acidosis could be implicated in perioperative complications, such as gastroparesis, emesis , and regurgitation of gastric contents. Implications: Metabolic and respir atory acidosis mainly affects gastric antral rhythms and has a major effect on fundic tone. Acidosis could be implicated in perioperative complication s, such as gastroparesis, emesis, and regurgitation of gastric contents.