 Patients admitted to the Emergency Department and triggering triage STOP SEPSIS ALERT based on triage vital signs and chief complaint, vomiting requiring zofran or diarrhea with concern for dehydrationhypovolemia, the treating physician believes would benefit from intravenous fluids, will be eligible for inclusion into this study. The treating physician refers to one of the Pediatric Emergency Medicine attendings or fellows, listed as co-investigators. Only if and when a patient or parent expresses interest in participating in the study, the attending or fellow caring for the patient will determine if the patient is eligible. If the patient is eligible, and has no criteria that would exclude them from the study, written informed consent will be obtained from the guardian and assent will be obtained in children 7 years old. The patient will be enrolled in the study and randomized to either the immediate ultrasonography group Ultrasound US of the Inferior Vena Cava IVC first before the clinician fully assesses the patient and places rehydration orders or the control group US at 15 minutes into the assessment and management of the patient. The goal will be to assess how the use of ultrasound impacts clinical management and outcomes in patients presenting to the pediatric emergency department with sepsis and dehydration. 