Hepatic and peripheral glucose metabolism in intensive care patients receiving continuous high- or low-carbohydrate enteral nutrition.
BACKGROUND
The suppression of endogenous glucose production during parenteral nutrition is impaired in critically ill patients. It is, however, unknown whether enteral administration of carbohydrates, which normally promote hepatic glucose uptake, improves hepatic glucose metabolism in such patients.


METHODS
We studied two groups of 7 patients during a 3-day continuous isocaloric enteral nutrition. A high-carbohydrate, low-lipid (EN-C) or a high-lipid, low-carbohydrate (EN-L) nutrient mixture was administered.


RESULTS
Endogenous glucose production assessed with [2H7]glucose was similarly increased in both groups, indicating absence of its suppression by carbohydrate feeding. Gluconeogenesis estimated from [13C]glucose synthesis during [13C]bicarbonate infusion also was not suppressed by EN-C compared with EN-L. Systemic appearance of exogenous glucose was monitored by enteral infusion of [6,6-2H]glucose and was not different from the rate of glucose equivalent administered enterally, indicating no significant hepatic uptake of glucose in both groups. Plasma glucose and insulin concentrations were slightly higher with EN-C, although not significantly, and plasma triglycerides were similar in both groups. Both nutrition formulas were well tolerated clinically.


CONCLUSIONS
These results indicate that enteral carbohydrate administration, whatever its quantity, fails to suppress endogenous glucose production and to promote net splanchnic glucose uptake in critically ill patients.
Tappy
L
L
Institute of Physiology, University of Lausanne, Switzerland.
Berger
M
M
Schwarz
J M
JM
McCamish
M
M
Revelly
J P
JP
Schneiter
P
P
Jéquier
E
E
Chioléro
R
R
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D002247:Carbon Isotopes; D003422:Critical Care; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D004750:Enteral Nutrition; D005260:Female; D005943:Gluconeogenesis; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000097:blood; D008099:Liver / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D002247:Carbon Isotopes; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D007328:Insulin; D014280:Triglycerides; D005947:Glucose