Boluses of Ringer's in Surgical Kids (BRiSK Study)

Inclusion Criteria: 1. Males or females age 12 months to 21 years. 2. Weight \>= 8 kg. 3. Patients with an uncomplicated abdominal or thoracic surgical procedure in which the expected postoperative length of stay is anticipated to be at least 2-5 days. 4. Patients admitted to a regular bed following surgery. 5. Patients who will be inpatient for approximately 4-8 days postoperatively. 6. Parental/guardian permission (informed consent). Exclusion Criteria: 1. Patients with a history of diabetes, seizures, hyperglycemia, and hypoglycemia. 2. Patients prescribed insulin. 3. Patients receiving parenteral nutrition. 4. Patients with excessive GI losses (small bowel obstruction, severe diarrhea, large-volume ascites or drainage). 5. Complicated surgery that requires an ICU or ICU transfer immediately after surgery. 6. Patients with any form of hypersensitivity to the study fluids. 7. Laboratory abnormalities that indicate clinically significant hematologic, hepatobiliary, or renal disease: * Serum Sodium \<130 or \>145 mmol/L * Serum Potassium \<3.0 or \>5.0 mEq/L * Serum Chloride \<90 or \>110 mEq/L * Serum Creatinine ≥ 1.6 mg/dL * Serum Glucose \<60 or \>180 mg/dL * Alanine Aminotransferase \>200 U/L * Total Bilirubin \>12.0 mg/dL 8. Pregnant or lactating females. 9. Parents/guardians or subjects who, in the opinion of the Investigator, may be non-compliant with study schedules or procedures.