Baseline Gastric Volume in Fasting Diabetic Patients Is Not Higher than That in Nondiabetic Patients: A Cross-sectional Noninferiority Study

BACKGROUND: The physiology of diabetes mellitus can increase the risk of perioperative aspiration, but there is limited and contradictory evidence on the incidence of "full stomach" in fasting diabetic patients. The aim of this study is to assess the baseline gastric content (using gastric ultrasound) in diabetic and nondiabetic patients scheduled for elective surgery who have followed standard preoperative fasting instructions. METHODS: This was a prospective, noninferiority study of 180 patients (84 diabetic and 96 nondiabetic patients). Bedside ultrasound was used for qualitative and quantitative assessment of the gastric antrum in the supine and right lateral decubitus positions. Fasting gastric volume was estimated based on the cross-sectional area of the gastric antrum and a validated model. The hypothesis was that diabetic patients would not have a higher baseline fasting gastric volume compared to nondiabetic patients, with a noninferiority margin of 0.4 ml/kg. Secondary aims included the comparison of the incidence of full stomach (solid content or more than 1.5 mL/kg of clear fluid), estimation of the 95th percentile of the gastric volume distribution in both groups, and examination of the association between gastric volume, glycemic control, and diabetic comorbidities. RESULTS: The baseline gastric volume was not higher in diabetic patients (0.81 ± 0.61 ml/kg) compared to nondiabetic patients (0.87 ± 0.53 ml/kg) with a mean difference of -0.07 ml/kg (95% CI, -0.24 to 0.10 ml/kg). A total of 13 (15.5%) diabetic and 11 (11.5%) nondiabetic patients presented more than 1.5 ml/kg of gastric volume (95% CI for difference, -7.1 to 15.2%). There was little correlation between the gastric volume and either the time since diagnosis or HbA1C. CONCLUSIONS: The data suggest that the baseline gastric volume in diabetic patients who have followed standard fasting instructions is not higher than that in nondiabetic patients. EDITOR’S PERSPECTIVE: