Preoperative Gastric Ultrasonography in Diabetic Versus Non-diabetic Patients Undergoing Elective Surgery: A Prospective Comparative Observational Study of Gastric Volume and Airway Management Implications

Background Pulmonary aspiration remains a serious perioperative complication associated with considerable morbidity and mortality. Although standard fasting guidelines are intended to minimize aspiration risk, patients with diabetes mellitus may experience delayed gastric emptying despite adequate fasting due to autonomic dysfunction and altered gastric motility. Point-of-care gastric ultrasonography has emerged as a practical bedside tool for evaluating residual gastric contents and may assist in perioperative airway planning. This study aimed to compare fasting gastric volume between diabetic and non-diabetic patients undergoing elective surgery using ultrasonography and to evaluate the distribution of airway management strategies according to preoperative ultrasonographic findings. Methods This prospective comparative observational study was conducted in the Department of Anesthesiology and Intensive Care at a tertiary care teaching hospital between June 2024 and November 2025. A total of 122 adult patients of either sex aged 30-75 years undergoing elective surgery under general anesthesia were enrolled and equally divided into Group C (non-diabetic, n = 61) and Group D (diabetic, n = 61). All patients underwent preoperative gastric ultrasonography after at least eight hours of fasting. Gastric antral measurements were obtained in both supine and right lateral decubitus (RLD) positions. Gastric cross-sectional area (CSA) and estimated gastric volume were calculated using standard formulas. Qualitative gastric grading was performed, and airway management strategies were selected according to ultrasonographic findings. Results Baseline fasting duration was similar between groups (8.6 ± 0.9 h vs 8.8 ± 0.9 h, p = 0.410). In the supine position, diabetic patients demonstrated significantly larger craniocaudal diameter (2.14 ± 0.14 cm vs 1.92 ± 0.18 cm), anteroposterior diameter (1.35 ± 0.08 cm vs 1.01 ± 0.09 cm), and gastric antral CSA (2.27 ± 0.19 cm2 vs 1.48 ± 0.20 cm2) compared with non-diabetic patients (p < 0.001 for all). Similar findings were observed in the RLD position, where diabetic patients had larger CSA values (3.34 ± 0.29 cm2 vs 1.52 ± 0.21 cm2) and significantly greater estimated gastric volume (10.3 ± 13.9 mL vs values consistent with negligible or empty gastric contents in non-diabetic patients; p < 0.001). Grade 0 gastric findings were more frequent among non-diabetic patients (67.2% vs 9.8%), whereas Grade 1 findings were predominant in diabetic patients (83.6% vs 31.1%) (p < 0.001). Rapid sequence intubation was performed more frequently in diabetic patients than non-diabetic patients (19.7% vs 3.3%; p = 0.004). Conclusions Diabetic patients demonstrated larger gastric antral dimensions and a higher prevalence of residual gastric contents on qualitative ultrasonographic assessment despite similar fasting duration. Preoperative gastric ultrasonography may help identify residual gastric contents and assist in perioperative airway risk assessment.