The usefulness of point-of-care ultrasound in dehydrated patients in a pediatric emergency department.

Backgrounds: Dehydration is among the most common causes of Pediatric Emergency Department admission; however, no clinical signs, symptoms, or biomarkers have demonstrated sufficient sensitivity, specificity, or reliability to predict dehydration.

Methods: We conducted a prospective, monocentric, observational study at Giannina Gaslini Hospital, a tertiary care pediatric hospital. Our study aimed to compare inferior vena cava ultrasound measurement with volume depletion biomarkers to understand if point-of-care ultrasound could help grade, evaluate, and better manage dehydration in children presenting to the pediatric emergency department. We enrolled patients under the age of 14 who required blood tests in the suspect of dehydration; for each patient, we collected values of venous pH, natremia, bicarbonatemia, uric acid, chloremia, and blood urea nitrogen. For each patient, we performed two ultrasound scans to calculate the Inferior Vena Cava/Aorta area ratio and to assess the IVC collapsibility index; moreover, we described the presence of the "kiss sign" (100% IVC walls collapsing during the inspiratory phase).

Results: Patients with the "kiss sign" (25/65 patients, 38.5% of the total) showed worse blood tests, in particular, uric acid levels (p = 0.0003), bicarbonatemia (p = 0.001) and natriemia (p = 0.0003). Moreover, patients with the "kiss sign" showed a high frequency of ≥ 2 pathological blood tests (p = 0.0002). We found no statistical significant difference when comparing the IVC/Ao ratio and IVC-CI with the considered blood tests.

Conclusions: The "kiss sign" seems to be related to worse hydration state, whereas IVC/Ao and IVC-CI are not. In an emergency setting, where physicians must take diagnostic-therapeutic decisions quickly, the presence of the "kiss sign" in patients suspected to be dehydrated can be a helpful tool in their management.