After institutional review board approval and written informed parental consent, ultrasound examination was performed in healthy full-term neonates before and after formula feeding at 15-min intervals until return to baseline. Ultrasound images of the gastric antrum were measured to obtain cross-sectional areas, which were then used to estimate gastric antral volumes.
Forty-six of 48 recruited neonates were included in the final analysis. Gastric emptying times ranged from 45 to 150 min and averaged 92.9 min (95% CI, 80.2 to 105.7 min; 99% CI, 76.0 to 109.8 min) in the overall study group. No significant differences were found in times to gastric emptying between male and female neonates (male: mean, 93.3 [95% CI, 82.4 to 104.2 min]; female: mean, 92.6 [95% CI, 82.0 to 103.2 min]; P = 0.930) or those delivered by vaginal versus cesarean routes (vaginal: mean, 93.9 [95% CI, 81.7 to 106.1 min]; cesarean: mean, 92.2 [95% CI, 82.5 to 101.9 min]; P = 0.819).
These results demonstrate that gastric emptying times are substantially less than the current fasting guideline of 6 h for formula-fed, healthy term neonates.
- The temporal kinetics of gastric emptying in formula-fed neonates are incompletely understood
- Currently, American Society of Anesthesiologists guidelines recommend 6 h of fasting in formula-fed neonates and infants before anesthesia
- Serial ultrasound imaging of the gastric antrum in healthy term neonates after formula feeding reveals gastric emptying times ranging from 45 to 150 min
- These observations suggest that preanesthesia fasting of healthy term neonates could be substantially shorter than is currently recommended