Ultrasound evaluation of gastric emptying time in patients undergoing elective thyroidectomy: a single-center prospective observational study

Abstract Background Aspiration risk can be reduced, but not completely prevented. Prolonged fasting may have adverse effects on patients, and evidence regarding optimal fasting times for Chinese adults remains insufficient. Therefore, our study aimed to evaluate the accurate gastric emptying time of formula breakfast and clear fluid in patients undergoing elective thyroidectomy using gastric ultrasound. Methods After obtaining informed consent, patients were instructed to eat a formula breakfast on the morning of the trial. For patients whose gastric antrum was at baseline before breakfast, the gastric antral cross-sectional area was observed every 30 min after breakfast until they returned to baseline. After emptying the breakfast, these patients voluntarily chose whether to drink water or not, and the gastric antral cross-sectional area was measured by gastric ultrasound every 30 min. Serial gastric ultrasound images of the gastric antrum were measured to obtain gastric antral cross-sectional area. Results 48 of 52 enrolled patients were included in the final statistical analysis of the study of gastric emptying time after breakfast. The time to gastric emptying of formula breakfast ranged from 90 to 240 min and averaged 186.3 ± 32.7 min (95% CI 176.8–195.8 min; 99% CI 173.6–198.9 min), and the median gastric emptying time was 180 min (interquartile range, 180–210 min). Of the 48 patients, 31 were included in the final statistical analysis of the study of gastric emptying time after drinking water. The time to gastric emptying of clear liquid ranged from 15 to 30 min and averaged 24.2 ± 7.4 min (95% CI 21.5–26.9 min; 99% CI 20.5–27.9 min), and the median gastric emptying time was 30 min (interquartile range, 15–30 min). Conclusions Our study demonstrated that the gastric emptying time of formula breakfast and clear fluid in patients undergoing electivee thyroidectomy was 186.3 ± 32.7 min and 24.2 ± 7.4 min, respectively. Trial registration Chinese Clinical Trial Registry (ChiCTR). Identifier ChiCTR2200059091.2022-04-24.