Does Point-of-Care Gastric Ultrasound Correlate With Reported Fasting Time?

Abstract

Objective: Traditionally, patient-reported fasting time has been the primary objective presedation measure of aspiration risk. Recently, gastric ultrasound has been used to assess gastric volume for the determination of aspiration risk in patients undergoing anesthesia in the operative setting. We sought to determine the correlation of gastric volume estimated by point-of-care ultrasound (POCUS) to reported fasting time.

Methods: We included children 4 to 18 years of age who presented with an acute traumatic injury. Enrolled children underwent POCUS to calculate gastric volume, which was calculated using a validated formula: Volume (mL) = -7.8 + (3.5 × Cross-sectional Area [CSA]) + (0.127 × Age in months). The CSA was measured (CSA = (anterior-posterior diameter × craniocaudal diameter × π)/4). We analyzed the relationship between time since last reported oral intake and measured gastric volume using Spearman rank correlation (ρ).

Results: A total of 103 patients with a median age of 10.5 years (interquartile range, 7.3-13.7 years) were enrolled. The gastric antrum was identified and measured in 88 (85%) patients; air obstructing the posterior surface of the gastric antrum prevented measurement in 14 of the 15 remaining patients. We observed a weak inverse correlation between fasting time (either liquid or solid) and estimated gastric volume (ρ = -0.33), with no significant difference based on type of intake (solids, ρ = 0.28; liquids, ρ = 0.22).

Conclusion: Gastric volume can be estimated by POCUS and is not strongly correlated with fasting time in children in the emergency department setting.