THE EFFECT OF 25 GRAMS IV GLUCOSE ON SERUM INORGANIC-PHOSPHATE LEVELS

Study objective: To determine whether a 25-g IV glucose bolus will res ult in a fall in serum inorganic phosphate levels. Design: Single-blin d, randomized, controlled trial. Participants: Thirty-six healthy, non diabetic, adult volunteers. Interventions: Random allocation to a cont rol group receiving a 50-mL normal saline bolus followed by a normal s aline infusion at 125 mL/hr for three hours; study group 1, receiving a 50-mL bolus of D50W followed by a normal saline infusion at 125 mL/h r for three hours; or study group 2, receiving a 50-mL bolus of D50W f ollowed by an infusion of 2/3:1/3 dextrose:saline solution at 125 mL/h r for three hours. Measurements and main results: Serum inorganic phos phate levels were measured at time zero (baseline) and at 30-minute in tervals for three hours. There was a statistically significant fall in serum inorganic phosphate levels in both groups receiving the glucose bolus. The group receiving the glucose infusion demonstrated a trend toward a further decline in serum phosphate levels. Conclusion: A gluc ose bolus and infusion in the amounts compatible with what is given to patients with altered levels of consciousness produced a significant fall in serum inorganic phosphate levels in healthy, nondiabetic adult s. Because hypophosphatemia may create a clinical picture of altered m ental status very similar to that of hypoglycemia, consideration shoul d be given to administering IV glucose only to patients with finger-st ick-proven hypoglycemia. Consideration also should be given to monitor ing phosphate levels after administration of IV glucose.