Ultrasound assessment of gastric emptying in premature infants treated
with non-invasive ventilatory support
Abstract
Abstract Background: Nasal CPAP introduces positive pressure of air into
both trachea and stomach, which may affect gastric emptying. The rate of
gastric emptying can be estimated by US by two validated techniques:
“antral cross-sectional area” (2-dimensional estimate of the surface
area at the gastric antrum), and “spheroid gastric volume”
(3-dimensional estimate of the stomach content volume). No study
examined gastric emptying rate in infants on bubble CPAP (bCPAP).
Objective: To compare gastric emptying rates in neonates on
machine-derived nasal CPAP (MD-nCPAP) with those on bCPAP. Methods:
Ultrasound measurements of the amount of milk in the stomach were
performed before feeding and at 1, 2, and 3 hours after the start of
feeding, using both the ACSA and spheroid methods. Rates of gastric
emptying were calculated during the “early” (1-2 hours) and “late”
(2-3 hours) phases after feeding. Results: We recruited 32 infants
(25-34 weeks gestational age). Seventeen infants were treated with
MD-nCPAP [median birth weight 1015 g (IQR: 870 to 1300), gestational
age 28 weeks (IQR: 27 to 29), postnatal age 20 days (IQR: 14 to 28)],
while 15 infants were treated with bCPAP [median birth weight 960 g
(IQR: 855 to 1070), gestational age 27 weeks (IQR: 26 to 28), postnatal
age 17 days (IQR: 15 to 25)]. Gastric emptying rates (% emptied/min)
were significantly faster in the “early” compared to the “late”
phase for all infants. There were no significant differences in the
rates of gastric emptying (either “early” or “late”) or volumes of
gastric residuals between infants receiving MD-nCPAP or bCPAP, measured
by either method. Conclusions: Gastric emptying is faster during the
“early” compared to the “late” phase. Gastric emptying rates are not
different in infants receiving MD-nCPAP vs bCPAP.