The purpose of the study is assessment of volume status by bedside ultrasound in children with acute gastroenteritis

The research will be conducted of emergency medicine department in the Derince Training and Research Hospital. Patients referred to acute gastroenteritis will be included to the study. After initial evaluation, the clinician will inform the principal investigator about the patient. The principal investigator will record the patient's demographic data, contact information, vital signs, history, physical examination findings, and weight. Than expirium and inspirium diameters of vena cava inferior will be measured with the bedside ultrasound and caval index will be calculated. An investigator who have had an ultrasound certification by Emergency Medicine Association of Turkey for six years will make the measurements. After 1 week the patient will called up for re-evaluation. Applicants' weights will be measured again with the same weighing machine. The differences between initial and after one week weight measurement will be accepted as the gold standard method for volume loss. The weight loss of the patient, the dehydration findings detected on physical examination and the caval index will be compared.

Data will be collected on predesigned data sheets, by an investigator and subsequently will be entered into a spreadsheet (Excel 2007; Microsoft, Redmond, WA). All recorded data will be checked by an another investigator to identify possible errors. Results will be submitted at least every two months.

Linear regression will be performed with dehydration as the dependent variable and the caval index as the independent variable.

Inclusion Criteria:

• Patients between 6 months and 18 years of age who presented to the Emergency Department with gastroenteritis

Exclusion Criteria:

• congenital heart disease
• chronic liver disease
• chronic renal disease
• patients or parents who doesn't want to enroll the study