Comparison of ultrasound-guided residual gastric volume measurement between diabetic and non-diabetic patients scheduled for elective surgery under general anesthesia

BACKGROUND AND AIMS: The presence of gastric content increases the risk of aspiration during general anesthesia. Diabetic patients have delayed gastric emptying; however, despite adequate fasting because of diabetic gastroparesis these patients have a high risk of aspiration. This study aimed to compare ultrasound-guided measurement of residual gastric volume between diabetic and non-diabetic patients scheduled for elective surgery under general anesthesia. METHODS: This prospective observational study included 80 patients divided into two groups of 40 diabetic patients with a minimum of 8 years history of diabetes and 40 nondiabetic patients aged >18 years, American Society of Anesthesiologists’ physical status I–II kept with similar fasting intervals. Before induction of general anesthesia, gastric ultrasound was performed using standard gastric scanning protocol to measure craniocaudal (CC) and anteroposterior (AP) diameters followed by calculation of antral cross-sectional area (CSA) and gastric volume in semi-sitting (SS) and right lateral decubitus (RLD) position using curved array probe. The gastric antrum volume (GV) was classified as Grade 0, 1, or 2, and risk stratification for aspiration was done. The nasogastric tube was inserted after induction of anesthesia to aspirate and compare the gastric content. RESULTS: In the semi-sitting position, the mean CC and AP diameters were 16.38 ± 3.31 mm and 10.1 ± 2.53 mm in the non-diabetic group and 25.19 ± 4.08 mm and 15.8 ± 3.51 mm in the diabetic group, respectively. In RLD, CC was 1.91 ± 0.38 cm and AP was 1.19 ± 0.34 cm in the non-diabetic group as compared to the CC of 2.78 ± 0.4 cm and AP of 1.81 ± 0.39 cm in the diabetic group. The calculated CSA of 318.23 ± 97.14 mm(2) and 4 ± 1.1 cm(2) in diabetic were significantly higher than 133.12 ± 58.56 mm(2) and 1.83 ± 0.83 cm(2) of non-diabetic, in SS (p < 0.0001) and RLD (p < 0.0001) positions, respectively. The GV of 15.48 ± 11.18 ml in the diabetic group was significantly higher than (-) 9.77 ± 18.56 ml in the non-diabetic group (p < 0.0001). Despite the differences in CSA and GV between diabetic and non-diabetic groups, both groups showed a low gastric residual volume (<1.5 ml/kg). The gastric tube aspirate in the non-diabetic and diabetic groups was 0.3 ± 0.78 ml and 1.24 ± 1.46 ml, respectively, and was statistically significant (p = 0.0006). CONCLUSION: Patients with long-standing diabetes showed higher gastric residual and antral CSA when compared with non-diabetic patients. The clinical significance of these findings needs further evidence for the formulation of specific guidelines for diabetic patients.