S980 Point of Care Gastric Ultrasound for Predicting Residual Gastric Content and Risk of Aspiration in Ambulatory Patients for Advanced Endoscopy Procedures

Abstract

Introduction: The risk of aspiration of gastric contents during endoscopy can be associated with significant morbidity and mortality. Even with complete fasting status, the gastric emptying times and residual gastric volumes other than basal secretions vary and depend on many patient factors. Bedside ultrasound imaging can be helpful in determining these gastric contents and volumes while enabling safe anesthesia practices. Our goals were to determine the gastric volume and compare the ultrasound guided gastric volumes in real time with endoscopist measured volumes. Methods: Patients presenting to the UAB endoscopy suite were taken written informed consent to participate in this study. The anesthesiologists experienced in performing gastric ultrasound performed the preoperative gastric ultrasound. The gastric cross-sectional area (CSA) is measured in supine and right lateral decubitus positions and gastric volumes calculated both using the nomograms and the formula. The anesthesia plan intraoperatively is based on the risk profile pattern of these gastric ultrasound estimates. The endoscopist blinded to these gastric ultrasound estimates performed endoscopy to suction the gastric volumes. These direct measured gastric volumes were then compared to calculated gastric volumes (CGV) to assess the degree of correlation and threshold values. Results: 81 patients were included in the study (Mean age 57.78 years, Male 49.38%, Mean BMI 29.83 patients). 2 patients were excluded as there was missing information or technical issues with documentation. Majority of patients underwent EUS (38.27%) followed by EGD ± therapy (30.86 %) ERCP (22.22%) and DBE (6.17 %). Mean CGV by nomogram is 33.84 ml, mean CGV by formula is 30.79 ml. Mean measures gastric volume by endoscopist is 28.64 ml. The gastric ultrasound was able to predict correlation significantly comparing measured gastric volume by endoscopy (ml) to CGV measured by nomogram (0.794, 95% CI for Pearson correlation (0.697-0.863) (Figure A) and measured gastric volume by endoscopy (ml) to CGV by formula (r=0.834 95% CI for Pearson correlation (0.753-0.890) (Figure B). There were no intra or post procedural adverse events noted in particular for aspiration. Conclusion: Gastric ultrasound acts as a reliable tool in predicting residual gastric volume and contents prior to undergoing anesthesia for advanced endoscopy procedures. This can potentially offer and guide preventive measures to prioritize on airway protection.Figure 1.: Measured gastric vol by