Glucose overload results in increased CO 2 production. Which of the following statements are true?

C. In Askanazi's study, increased CO 2 production and difficulty in weaning was associated only with pronounced overfeeding.

DISCUSSION: Few papers have excited as much interest as that by Askanazi, Kinney, and co-workers, which demonstrated that glucose calories given to patients with severe respiratory impairment may result in difficulty in weaning from a respirator. Subsequent research has suggested, however, that this occurs only with severe overfeeding, when the respiratory quotient is greater than 1 and calories are excessive. If one examines the conditions under which Askanazi's patients were studied, these were a group of septic, depleted patients who were taken from almost no nutritional support to a caloric supply of 2.25 times their caloric requirement, most of the calories consisting of glucose. Suffice it to say that, in patients with impaired respiratory function, one should measure VCO2 and, when VCO2 is significantly elevated and appears to interfere with weaning, decrease the amount of glucose calories and increase the amount of fat. If one measures or estimates calorie requirements and does not overfeed, lipid can be utilized for 25% of the caloric requirement and glucose for the remainder, without much fear of excessive CO 2 production.