Abstract
BACKGROUND: Because carbohydrate metabolism results in the production of carbon dioxide (CO2), spontaneously breathing patients with the inability to increase minute ventilation (VE) in the face of an increase in CO2 load from car-bohydrate intake may develop CO2 retention and respiratory acidosis. Also, con-trol of carbohydrate intake in patients with diabetes mellitus is necessary. Crit-ically ill patients often receive intravenous 5% dextrose infusions in addition to their nutritional support regimens for medication delivery and systemic hydration. We sought to quantitate the contribution of such infusions to the total caloric intake and the proportion of carbohydrate provided. METHODS: We measured resting energy expenditure daily by direct calorimetry and quantified the con-tribution of the dextrose solutions to carbohydrate and total caloric intake in a group of 17 critically ill, mechanically ventilated postoperative patients studied for a total of 143 patient-days. Total carbohydrate intake, total caloric intake, caloric intake from nutritional support formulations, and caloric intake from intravenous 5% dextrose were computed. 5% dextrose was provided on 123 of 144 study-days, with intake from intravenous 5% dextrose ranging from 20 to 934 Kcal/day with mean (SD) of 150 (140), which represented from 1-43% of the total caloric intake 12 (18)%. RESULTS: 5% dextrose intake provided an average of 12% of all calories and increased the proportion of carbohydrate-to-total calories from 37 to 50%. CONCLUSION: The amount of intravenous 5% dextrose should be considered when designing and monitoring nutritional support regimens, par-ticularly in patients with marginal pulmonary function.
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