O1024: Point-of-Care Ultrasound Evaluation of the Accuracy of Reported Fasting Status and Factors Impacting Gastric Emptying in Pediatric Emergency Department Patients

Background: Procedural sedation and analgesia (PSA) is commonly used in the pediatric emergency department (PED) for patients undergoing urgent interventions. Historically, many providers utilized the American Society for Anesthesiology (ASA) nil per os (NPO) guidelines to inform the timing of PSA, often resulting in delays in care. Research has shown that reported fasting status does not affect the safety of pediatric PSA, and further, is not a reliable measure of gastric content in PED patients. We sought to evaluate the accuracy of NPO timing in predicting measured gastric content as determined by point-of-care ultrasound (POCUS) in PED patients and to evaluate factors associated with ‘non-expected’ gastric emptying in this patient population.

Methods: The IRB-approved, prospective observational study used a convenience sample of patients aged 6 months to 17 years presenting to the PED between July 1, 2018 and June 30, 2019. Patient demographics, history, and last oral intake were recorded. Patients were kept NPO, and their gastric contents were measured and classified with POCUS using the Perlas Model every 2 hours until discharge or PSA. Measured gastric content was compared to ‘expected’ gastric content based on NPO timing per the ASA guidelines. Statistical analyses were performed to characterize patient demographics and factors associated with gastric emptying.

Results: The study enrolled 192 patients with a mean age of 7.3 years and male predominance (58.9%). Gastric content was determined in 218 of 226 (96.5%) total measurements, and gastric volume was quantified in 140 (61.9%). Patients were reported ‘fasting’ by ASA guidelines in 25.7% of measurements. NPO timing predicted gastric content in 75.2% of measurements overall, but only 37.5% in ‘fasting’ patients. Gastric emptying was classified as ‘expected’ in 164 (75.2%) measurements, ‘delayed’ in 35 (16.1%), and ‘expedited’ in 19 (8.7%). A weak inverse correlation between fasting time and gastric volume was observed (r = -0.28, p < 0.001). ‘Delayed’ emptying was associated with reported pain scores >7 (p = 0.002), worst pain (p = 0.050) and longer length of stay (p = 0.020). Different illness presentations including trauma (p = 0.417) and infection/GI illness (p = 0.352), and narcotics use prior to the PED (p = 0.269), in the PED (p = 0.998), and prior to PSA (p = 0.744) did not contribute to gastric emptying differences overall.

Conclusion: In PED patients, reported NPO time is frequently inconsistent with measured gastric content, particularly in ‘fasting’ patients. High pain scores and longer length of stay were significantly associated with ‘delayed’ gastric emptying. Such factors are common to many patients who require PSA or non-elective operative intervention. The use of POCUS in these settings should be considered to improve the accuracy of gastric content determination compared to relying on reported NPO timing alone.