2 year-old male had a recent adjustment in parenteral nutrition infusion cycle from 18 to 12 hours. There was no change in PN concentration. As a result, the glucose of infusion rate changed from 14 to 25 mg/kg/minute. Mother calls to complain that has symptoms of polydipsia and dehydration during daytime. During overnight PN, the patient is voiding more frequently. What is the most likely problem?
The correct answer is d. Typically, PN infusions should be adjusted slowly to allow for metabolic compensations. When PN rates or concentrations are adjusted, the glucose infusion rate should be calculated. Typically, the glucose infusion rate may be increased by 2 mg/kg/minute with each PN change. It had been thought that patients could tolerate a maximal glucose infusion rate of 14 mg/kg/minute. Some patients may tolerate glucose infusion rates much higher anecdotally – however, this must be done with caution and monitoring. A side effect of infusing glucose higher too fast is hyperglycemia. Symptoms of hyperglycemia include polyuria, polydipsia, and hyperphagia. You can monitor tolerance of rising PN glucose infusion rate by checking blood sugar during PN infusion or urine dipstick (generally normal kidneys spill glucose when blood sugar >190).