Sonographic assessment of fasting: emergency room sedations

Aspiration during emergency department (ED) procedural sedation is exceedingly rare but remains a key safety concern. Assessment of aspiration risk is a fundamental element of sedation risk assessment, yet fasting status, a common surrogate, has limited predictive value. This study evaluated whether self-reported fasting reliably predicts gastric contents in adult ED patients, as assessed by point-of-care ultrasound (PoCUS).

We conducted a prospective observational study of adults presenting to a Canadian academic ED (Aug 2024-May 2025). Participants reported their last oral intake and underwent gastric PoCUS using standardized imaging. Three blinded reviewers classified contents as low risk (empty/clear fluids) or high risk (solids). The primary outcome was the presence of solid gastric contents relative to fasting duration.

A total of 122 participants (mean age 52.2 years; 51.6% female) were enrolled. The gastric antrum was visualized in all cases, with strong inter-rater reliability (κ = 0.79). Solid contents were present in 78.9% of patients fasting less than 8 h and 58.1% fasting greater than 8 h (risk difference 20.8%, p = 0.014). The prevalence of solid contents declined with increasing fasting time: 92% at 0-4 h, 68% at 4-8 h (p = 0.049), and 58% at greater than 8 h (p = 0.012). Mean fasting duration was shorter in patients with solids (9.4 h) compared with those without (13.4 h).

Self-reported fasting duration was an unreliable predictor of gastric contents, with more than half of patients fasting for greater than 8 h still demonstrating solids on PoCUS. Gastric PoCUS may offer an accurate adjunct for assessment of gastric contents in patients undergoing ED procedural sedation.