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 non-diabetic patients, scheduled for elective surgery, who have followed standard pre-operative fasting instructions.

Methods

This was a prospective, non-inferiority study of 180 patients (84 diabetics and 96 non-diabetics). 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 (CSA) of the gastric antrum and a validated model. We hypothesized that diabetic patients would not have a higher baseline fasting gastric volume compared to non-diabetic patients, with a non-inferiority margin of 0.4 mL/kg. Secondary aims included the comparison of the incidence of “full stomach” (solid content or >1.5mL/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 non-diabetics (0.87 ± 0.53 mL/kg) with a mean difference of -0.07 mL/kg (95% CI: -0.24 to 0.10 mL/kg). Thirteen (15.5%) diabetic and 11 (11.5%) non-diabetic patients presented > 1.5 mL/Kg of gastric volume (95% CI for difference: -7.1%, 15.2%). There was little correlation between the gastric volume and either the time since diagnosis or HbA1C.

Conclusion

Our data suggest that the baseline gastric volume of diabetic patients who have followed standard fasting instructions, is not higher than that of non-diabetics.