Vital signs and fluid management/replacement therapy recorded in the medical chart and results of standard complete blood count (CBC), biochemistry, and hematology and coagulation lab panels will be reviewed and recorded by research staff at specified time points, according to the hospital standard of care. Additionally, research staff will review and record daily lactate, urine albumin, blood urea nitrogen (BUN), creatinine, and non-invasive measurements at the following time points: Baseline, 6hr, 12hr, 24hr, 36hr, 48hr, and 72hr post-onset of hypovolemia), until hemodynamic stability is achieved. Hemodynamic stability will be evaluated based on site-specific age-defined reference ranges for heart rate, blood pressure, urine output, and cardiac index in children.