Ultrasound of the Inferior Vena Cava (IVC) and Dehydration Status in Pediatric Emergency Patients

Objective: Although approximately 9% of patients presenting to a Pediatric Emergency Department (ED) are dehydrated, there is no reliable method to measure objectively the degree of intravascular dehydration. Respiratory changes in Inferior Vena Cava (IVC) diameter have been shown to predict volume status in adults. Previous research has demonstrated correlation between IVC diameter and volume status in children undergoing hemodialysis. Other studies have shown that IVC diameter in children can be sonographically measured rapidly and accurately by ED physicians. If we can establish that IVC diameter predicts volume status in dehydrated children, this tool could assist the ED physician in rapid diagnosis and prompt resuscitation without the need to wait for blood or urine tests. In this study we use the "dehydrated patient" as a model for hypovolemia, with the idea that the data could ultimately be used in the setting of any hypovolemic state. We aim to evaluate whether ultrasound of the pediatric IVC can be used to reliably assess volume status. Methods: This is a prospective cohort study. Pediatric ED patients ranging in age from 1 to 41 months were assessed by a Pediatric emergency physician and stratified as either clinically euvolemic or hypovolemic. After consent was obtained, one of three Emergency Medicine Residents performed trans-abdominal sonographic measurements of the IVC diameter. Measurements of the IVC diameter just caudal to the insertion of the hepatic veins were obtained in a longitudinal orientation.