The purpose of this study is to evaluate predictability of an abdominal compression-induced change of blood pressure for fluid responsiveness in children.

The purpose of this study is to evaluate predictability of an abdominal compression-induced change of blood pressure for fluid responsiveness in children.

When there are clinical signs of hypovolemia, such as hypotension, decreased urine output and central venous pressure less than 5 mmHg, right upper abdomen is gently compressed for 10 seconds. Changes of blood pressure are continuously recorded during this period. About 3 min later, intravenous colloid fluid 10 mL/kg is infused for 20 min.

To evaluate the change of cardiac output, transesophageal or transthoracic echocardiography is performed before and after fluid administration. In addition, hemodynamic parameters including pulse pressure variation, systolic pressure variation, pleth variability index and central venous pressure are also recorded before and after fluid administration.

Finally, patients will be divided into fluid responder group and non-responder group. If cardiac output measured using echocardiography increases over 15% after fluid administration, the patient is fluid responder. Using ROC curve, diagnostic power of abdominal compression-induced blood pressure change for fluid responsiveness will be evaluated.

Inclusion Criteria:

• Pediatric patients undergoing elective surgery, who require invasive blood pressure and central venous pressure monitoring during surgery

Exclusion Criteria:

• renal, hepatic and pulmonary disease
• preoperative infection: increased CPR, WBC over 10,000, and with fever
• genetic and hematologic disease
• intracardiac and extracardiac shunt
• single ventricle
• right heart dysfunction
• any intracardiac valve pathology
• increased intracranial pressure