Current guidelines recommend preoperative fasting of 2 h for clear fluids, which is often exceeded in routine clinical practice. Existing data on residual gastric volumes in children do not consider fluid intake within <2 h and rely on the aspiration of gastric contents via a gastric tube. This study evaluated the emptying of clear fluids from the stomach using magnetic resonance imaging (MRI).Methods
Healthy volunteers aged 6–14 years were asked to fast overnight. MRI scans to assess gastric volumes were obtained before and immediately after drinking 7 ml kg−1 of diluted raspberry syrup and then every 30 min up to 120 min. Volumes were determined by a blinded investigator and indexed gastric fluid/air volumes (GFVw/GAVw) and half-life (t1/2) of GFVw course after clear fluid intake were calculated.Results
Sixteen children, median age 9.2 (range 6.4–12.8) years, were investigated. Median (range) GFVw was 0.62 (0.15–0.97) ml kg−1 before and 6.68 (4.77–7.78) ml kg−1 immediately after fluid intake, and 2.92 (0.43–5.04), 1.27 (0.28–3.62), 0.42 (0.07–2.49), and 0.32 (0.04–1.13) ml kg−1 30, 60, 90, and 120 min thereafter. Median GFVw declined exponentially (t1/2=26.1 min). Median individual t1/2 was 23.6 (range 17.9–47.8) min. GAVw showed considerable intra- and inter-individual variation.Conclusions
In healthy school children, gastric emptying after ingestion of clear fluid occurs with a median half-life time of <30 min but with considerable inter-individual variation.