Ultrasound-Based Assessment of Gastric Fluid Volume in the Pediatric Population Undergoing Elective Surgery: A Prospective, Randomized, Double-Blind Comparison of Carbohydrate-Rich Clear Fluid Versus Water at One- and Two-Hour Fasting Intervals

Preoperative fasting guidelines have evolved from the traditional "nil per os after midnight" rule toward more liberal regimens. The European Society of Anaesthesiology and Intensive Care (ESAIC) and the Association of Pediatric Anesthetists of Great Britain and Ireland (APAGBI) now recommend a one-hour clear fluid fast for children, yet objective evidence quantifying the gastric fluid volume (GFV) resulting from carbohydrate-rich clear fluids at this abbreviated interval remains limited.

To evaluate the effect of one- versus two-hour fasting following the ingestion of 3 mL/kg of a carbohydrate-rich clear fluid or plain water on GFV, as assessed by point-of-care gastric ultrasound (POCUS), in healthy children undergoing elective surgery.

In this prospective, randomized, double-blind, parallel-group trial (CTRI/2024/01/061823) conducted at a tertiary referral centre from February 2024 to March 2025, 140 ASA I-II children aged 1-12 years undergoing elective non-gastrointestinal surgery were randomized to one of four groups: (A) 10% glucose solution (Glucon-D), 1-h fast; (B) 10% glucose solution, 2-h fast; (C) plain water, 1-h fast; (D) plain water, 2-h fast. All children received 3 mL/kg of the assigned fluid and fasted for the designated interval before POCUS assessment. The primary outcome was GFV in the right lateral position (RLP), calculated using the Spencer formula. Secondary outcomes included GFV distribution across three risk thresholds (0.8, 1.25, and 1.5 mL/kg), antral cross-sectional area (CSA) in supine and RLP, qualitative Perlas antral grading (Grades 0-2), prevalence of pulmonary aspiration, and Visual Analogue Scale (VAS) comfort scoring.

All 140 enrolled children completed the study. Mean GFV in RLP was highest in Group A (0.947 ± 0.225 mL/kg), followed by Group C (0.825 ± 0.179 mL/kg), Group B (0.340 ± 0.317 mL/kg), and Group D (0.268 ± 0.322 mL/kg) (one-way ANOVA, p < 0.001). No participant in any group exceeded a GFV of 1.5 mL/kg. In Group A, 57.1% of children had GFV between 0.9-1.25 mL/kg; 91.4% of Group B and 100% of Group D had GFV ≤ 0.8 mL/kg. Perlas Grade 2 was observed in 31.4% of Group A and 8.6% of Group C; none in the two-hour groups. VAS comfort scores were significantly higher in Group A (8.31 ± 0.63) compared to Group D (6.66 ± 0.97) (p < 0.001). No episodes of pulmonary aspiration occurred.

Consumption of 3 mL/kg of a carbohydrate-rich clear fluid 1 h before anesthesia induction produces higher but clinically safe GFV (none exceeding 1.5 mL/kg) and superior patient comfort compared to conventional two-hour fasting. These findings provide prospective, quantitative support for the implementation of one-hour clear fluid fasting protocols in healthy pediatric patients undergoing elective surgery.

The trial was registered prospectively with the Clinical Trials Registry (India), CTRI/2024/01/061823.