Intravenous nutrition does not have a positive effect on the recovery of critically ill patients if it is administered early. Recovery from critical illness is in fact faster when patients receive supplementary intravenous nutrition one week after their admission to intensive care.
Critically ill patients receive intravenous nutrition – via an infusion in a large vein – when nutrition via a stomach or intestinal tube is insufficient. There is international dispute over the correct timing of intravenous nutrition: European guidelines recommend administering intravenous nutrition within 48 hours to prevent malnutrition. In the United States and Canada, intravenous nutrition is administered after 8 days because it also has disadvantages, such as increased blood sugar levels. Because the food is administered directly into the blood, there is no natural reflex to balance the blood sugar level. Increased blood sugar levels damage cells in critically ill patients.
In a study led by Professor Greet Van den Berghe and Dr. Michael Casaer of the Department of Intensive Care Medicine at K.U.Leuven, 4,640 patients were monitored and treated in seven intensive care units in Leuven and Hasselt. The two systems of intravenous nutrition were compared, while elevated blood sugar levels were avoided with insulin.
Despite the very limited intake of food, patients who only received intravenous nutrition after a week had a greater chance of leaving the intensive care unit more quickly and without complications. They had fewer infections and reacted more efficiently to them, spent less time on respirators or dialysis machines and had fewer liver problems. As a result, the patients recovered more quickly.
According to professor Van den Berghe, the explanation is to be found in the natural cleaning system of the cells. “Critical illness causes damage to the cells of all vital organ systems. Damaged mitochondria – energy factories in cells – and functional proteins can only be cleared by autophagy: a cleaning system that is activated by fasting and which is suppressed by feeding. In additional experimental research, we demonstrated that a lack of food during the first week of serious illness improves the clearing of such cell damage.”