Effects of peristaltic amplitude and frequency on gastric emptying and mixing: a simulation study

The amplitude and frequency of peristaltic contractions are two major parameters for assessing gastric motility. However, it is not fully understood how these parameters affect the important functions of the stomach, such as gastric mixing and emptying. This study aimed to quantify the effects of peristaltic amplitude and frequency on gastric mixing and emptying using computational fluid dynamics simulation of gastric flow with an anatomically realistic model of the stomach. Our results suggest that both the increase and decrease in peristaltic amplitude have a significant impact on mixing strength and emptying rate. For example, when the peristaltic amplitude was 1.2 times higher than normal, the emptying rate was 2.7 times faster, whereas when the amplitude was half, the emptying rate was 4.2 times slower. Moreover, the emptying rate increased more than proportionally with the peristaltic frequency. The nearest contraction wave to the pylorus and the subsequent waves promoted gastric emptying. These results suggest the importance of maintaining parameters within normal ranges to achieve healthy gastric function.

Automated summary

The amplitude and frequency of peristaltic contractions have a significant impact on gastric mixing and emptying. Increasing or decreasing the amplitude affects mixing strength and emptying rate, with higher amplitude increasing the emptying rate and lower amplitude decreasing it. The emptying rate also increases with the peristaltic frequency. The closest contraction wave to the pylorus and subsequent waves promote gastric emptying. It is important to maintain these parameters within normal ranges for healthy gastric function.