Profile of 24-hour plasma glucose and insulin concentrations. Their variation with two methods of total parenteral nutrition administration.

The concentration of glucose and insulin in the plasma during total parenteral nutrition (TPN) was measured every 20 minutes during a 24-hour period in three subjects with granulomatous enterocolitis. During a gravity drip, parallel variations in rate of flow and plasma glucose and insulin concentrations were seen, and both hypoglycemia and hyperglycemia occurred. During a constant (pumped) infusion, plasma glucose and insulin concentrations were stable and normal. Glucose excretion in the urine was negligible and adequate gains in weight occurred, suggesting utilization of the administered nutrients. Hypertonic solutions for TPN should be infused at a constant rate either by careful attention to the flow rate during changes of intravenous bottles and tubing or by using a constant-infusion pump. Infusion of TPN solutions at a constant rate minimizes the risk of hypoglycemia or hyperglycemia.