Diagnostic accuracy of a simple qualitative ultrasound assessment for the diagnosis of empty stomach in the adult: A supplementary analysis of a prospective observer-blind randomized crossover study.

BACKGROUND: It has been reported that qualitative ultrasound assessment performed in the semi-upright position had high sensitivity to detect gastric fluid volume >1.5 mL.kg-1 . Nevertheless, the diagnostic accuracy of qualitative assessment for the diagnosis of empty stomach (fluid volume <0.8 mL.kg-1 ) has not been assessed. We aimed to assess the diagnostic accuracy of simple qualitative ultrasound assessment with and without head-of-bed elevation to 45° for the diagnosis of an empty stomach. We also aimed to determine the diagnostic accuracy of a composite ultrasound scale and clinical algorithm.

METHODS: We performed a supplementary analysis of a prospective observer-blind randomized crossover trial in which adult fasting volunteers attended two distinct sessions, with the head-of-bed angled either at 0° or 45°, in a randomized order. Three tests were performed within each session, each corresponding to a different (either 0, 50, 100, 150 or 200 mL) and randomized volume of water; the same volumes were ingested in both sessions, in a randomized order. Ultrasounds were performed 3 min after water ingestion, blindly to the volume ingested.

RESULTS: We included 20 volunteers in whom 120 measurements were analyzed. The sensitivity and specificity of the qualitative assessment in the semirecumbent position were 93% (95% CI: 68-100) and 89% (95% CI: 76-96), respectively. The composite scale and clinical algorithm did not have better diagnostic accuracy than the qualitative assessment performed with head-of-bed elevation. Without head-of-bed elevation, the clinical algorithm had significantly higher specificity (98% [95% CI: 88-100]) than qualitative assessment (67% [95% CI: 51-80]; p < 0.05).

CONCLUSION: These results suggest that qualitative assessment in the semirecumbent position had high diagnostic accuracy for the diagnosis of fluid volume <0.8 mL.kg-1 ; this method can be used in clinical practice for reliable diagnosis of empty stomach.