The effect of varying amounts of intravenous glucose on the metabolic changes after surgery.

The metabolic effects of saline, 30 of glucose a day and 129 g of glucose a day were studied in patients after either cholecystectomy or highly selective vagotomy. In the saline group the blood ketone concentration increased to 3.3 mmol/l on the 5th day after surgery, but this increase was completely abolished by a daily intake of 129 g of glucose and almost completely so by 30 g of glucose. Urine nitrogen excretion expressed as nitrogen to creatinine ratio in the saline group increased from 42.5 to 66.2 by the third day after surgery, and there was a similar increase in the group given 30 g a day of glucose. However, 129 g/day of glucose completely prevented the increase in urine nitrogen, an effect which is similar to that reported in starving subjects given similar amounts of glucose. It is suggested that 129 g of glucose only prevents that part of the increase in nitrogen excretion which is due to starvation and that it has no effect on the increase in nitrogen excretion which happens as part of the metabolic response to surgery.