Patients admitted to the PICU with septic shock; Hypotension (systolic blood pressure less than 2 standard deviations below age normal) plus 3 or more of the following: temperature greater than 38 or less than 36 degrees Celsius; heart rate greater than 90th percentile for age; respiratory rate greater than 90th percentile for age; WBC greater than 12,000/mm3 or less than 4,000/mm3 or greater than 10% band forms; perfusion abnormalities including lactic acidosis, oliguria, or an acute alteration in mental status