The Correlation between Ultrasonographic Gastric Antral Area and Vomiting in Patients undergoing Procedural Sedation and Analgesia

Aspiration of gastric contents is one of the most important complications during procedural sedation and analgesia (PSA). It seems that gastric ultrasonography could be a suitable tool for qualitative and quantitative measurement of gastric contents before PSA. 

In the present study, efforts were made to assess the correlation between ultrasonographic gastric antral area and incidence of vomiting in patients underwent PSA. 

In the present cross-sectional study, using a convex 4MHz probe in supine position, ultrasonographic evaluation of gastric antral area was done for 100 participants in need of PSA. The evaluations were done from the outer layer of the gastric wall and 3 images were recorded between peristaltic contractions. Finally, the rate of vomiting incidence in patients were recorded and compared with the results of patients’ ultrasonography. 

The findings showed that anteroposterior diameter (AP), craniocaudal diameter (CC), and cross-sectional area (CSA) had a statistically significant correlation with incidence of vomiting in patients (p ≤ 0.0001). The odds ratio of these variables show that increase in antral diameter leads to increase incidence of vomiting. Based on these findings, 1 unit rise in AP increases the odds of vomiting by 7.45 times, 1 unit increase in CC increases the odds by 7.20 times, and finally, 1 unit increase in CSA increases the odds of vomiting by 1.32 times. 

Gastric antrum ultrasonography can be used as a proper diagnostic tool for assessing the risk of vomiting in patients undergoing PSA.