Diagnostic performance of qualitative ultrasound assessment for the interpretation of point-of-care gastric ultrasound to detect high gastric fluid volume: A prospective randomized crossover study

Abstract

Study objectiveThis study aimed to assess whether elevating the head of the bed to 45° was associated with sensitivity >90% of the qualitative ultrasound assessment for the diagnosis of gastric fluid volume > 1.5 ml.kg−1. We also assessed the performance of qualitative assessment, composite ultrasound scale, and clinical algorithm, for the diagnosis of fluid volume > 1.5 ml.kg−1 according to whether the head of the bed was elevated to 45° or not. DesignProspective randomized observer-blind crossover trial. SettingHospices Civils de Lyon, France. PatientHealthy adult volunteers. InterventionsTwo separate study sessions in fasting volunteers: with and without head-of-bed elevation to 45°, in a randomized order. Each session consisted of three tests, each corresponding to a randomized and different volume of water (either 0, 50, 100, 150 or 200 ml); the same volumes were used in both sessions and in a randomized order. Gastric ultrasounds were performed three minutes after the ingestion of water by an investigator blinded to the volume ingested. MeasurementsDiagnostic performance of each approach for the diagnosis of gastric fluid volume > 1.5 ml.kg−1. Main resultsTwenty volunteers were included, and 120 measurements were analyzed. The sensitivity of the qualitative assessment for the diagnosis of gastric fluid volume > 1.5 ml.kg−1 with and without head-of-bed elevation was 91% (95%CI: 75–98) and 75% (95%CI: 57–89), respectively. The clinical algorithm with head-of-bed elevation had significantly better sensitivity than the qualitative assessment with no head-of-bed elevation; there was no significant difference for other comparisons. ConclusionsThe results suggest that qualitative examination of gastric antrum in the supine position with head-of-bed elevation to 45° can discriminate between low and high gastric fluid volume with high sensitivity, while neither the composite ultrasound scale nor the clinical algorithm improved the diagnostic performance of gastric ultrasound for the diagnosis of gastric fluid volume > 1.5 ml.kg−1.