Introduction The world health organization defines dehydration as condition that result from excessive loss of body water .the most common cause of dehydration in children are vomiting and diarrhea. Dehydration is a major cause of morbidity and mortality in infant and young children world wide .most cases due to consequence of acute gastroenteritis.~Pathophysiology. Dehydration cause decrease in total body water in both intracellular and extracellular fluid volume. Volume depletion closely correlate with sign and symptom of dehydration .the total body water is higher in infant and children compared to adult.~In infant, it is 70% of total body weight, whereas it is 65%and 60% respectively in children and adult.~The World Health Organization recommends assessing dehydration in children based on four clinical features: general appearance , eyes (whether they appear sunken), history of thirst , and skin pinch to assess turgor. However, these clinical signs may be subtle or non specific and thus have important limitations if used as independent predictors of dehydration. A more objective way to assess for dehydration using urine analysis has been implicated.~Additionally, studies on dehydration have shown urine analysis do not show sufficient sensitivity, Specificity or reliability [3, 4] and are typically only useful in children with moderate to severe hypovolemia.~. Bedside ultrasonography is a noninvasive method that can serve as a more objective tool for assessing dehydration in both adults and children. Point-of-care ultrasound has the potential to reduce unnecessary use of resources such as IV fluids or hospital access, while identifying children who are severely dehydrated and need immediate medical attention. Previous studies have shown that intravascular volume correlates to the diameters of the inferior vena cava.~The normal IVC diameter is 15_ 17mm~small IVC (usually < 12mm) with spontaneous collapse is often seen in the presence of intravascular volume depletion.~Bedside emergency ultrasonography (EUS) is a relatively new imaging modality in pediatrics.(8,9) EUS is fast, painless, and noninvasive. In recent years, many new pediatric indications for EUS have been developed.~Ultrasonography (US) assessment of the inferior vena cava (IVC) has been used as a noninvasive diagnostic tool for the assessment of intravascular volume and right heart function. Specifically, IVC diameter and collapsibility have been used as methods of assessing fluid status in dehydrated patients .~In these studies, contraction of the intravascular volume resulted in measurable decreases in IVC diameters. Conversely, research has shown that the diameter of the descending aorta (Ao) remains mostly constant, despite intravascular volume depletion.
IVC Index in patient with Diarrhea and Dehydration And How It affects its management.