The excretion of sugars after the intravenous administration of invert sugar.

Until recently glucose was the only sugar used for intravenous administration. Glucose was indeed the obvious choice, for it is constantly present in the blood and it also occupies a central position in carbohydrate metabolism. The results obtained by the intravenous administration of glucose are satisfactory. However, if glucose in a higher concentration than 500 is used difficulties may ensue. The wall of the blood vessel is affected by the hypertonic glucose solution, with the result that in many cases thrombi develop, and continued administration in the same vessel becomes impossible. Moreover, the intravenous administration of large quantities of 1000 glucose causes glycosuria and results in increased diuresis. Not only is part of the glucose again lost in this way. but also the patient loses more fluid than was administered. In many cases in which fluid is administered intravenously this is undesirable. Other nutrients were therefore sought from which to prepare a liquid of high caloric value for intravenous administration. As long as intravenous administration of fat is still in the experimental stage. only carbohydrates and amino-acids should be considered as sources of calories. The highest concentration of amino-acids which can be given intravenously in larger quantities is about 5 If amino-acids are given fairly rapidly in higher concentration, nausea and vomiting will soon occur so that any increase in the caloric value of the infusion liquid must be by increasing the carbohydrate content. An infusion liquid containing 100% carbohydrate and 500 amino-acid has a nutrient value of 600 calories per litre. With such a liquid it is possible, provided the excretion of sugar and amino-acids in the urine is small, to meet to a great extent the caloric need of a patient. Weichselbaum, Elman and Lund (1950) suggested giving invert sugar instead of glucose. They observed that if I0V, invert sugar and 10% glucose were administered at the same rate, the amount of carbohydrate in the urine after administration of glucose was about twice as great as after giving invert sugar. Although fructose is less readily reabsorbed by the kidney than glucose, the rate of utilization of fructose in the body is so high that the fructose level of the blood remains low. The result is that excretion of fructose hardly takes place. This is due to the fact that fructose is absorbed more rapidly by the cells and phosphorylated than is the case with glucose (Cori, 1926). The phosphorylated product is then easily broken down by the organism into pyruvic acid. while at the same time glycogen may be formed (Soskin and Levine, 1952). There are signswhich show that for carbohydrate metabolism liver tissue prefers fructose to glucose (Vestling, Mylroie, Irish and Grant, 1950). In some more recent reports the original observations by Elman are corroborated. It is a remarkable fact that the reaction of the vascular wall to l0 o glucose is greater than to I0 o invert sugar. Lawton, Curreri and Gale (1951) on the other hand consider the advantages of invert sugar less important. The excretion during administration of 10bo glucose is, according to them, not so great that the use of invert sugar is a marked caloric improvement. A secondary advantage is reduced diuresis after the administration of invert sugar. The above-mentioned authors all carried out their observations on adults. However, the problem is also of importance in children, for it is desirable to have an infusion liquid available which will provide by intravenous alimentation not only sufficient fluid but also enough calories. Even more than in adults it is important in the growing child to maintain a caloric balance during acute disorders. For this reason we have studied the retention of intravenously administered invert sugar in children. In connexion with the investigations by Elman we studied first the excretion of fluid and carbohydrates in a number of children who for 24 hours received either 10 o glucose or 10°o invert sugar. These children had been admitted to hospital for