title: Variation in the resting metabolic rate of mechanically ventilated critically ill patients.
abstract: There has been increasing interest in the nutritional support of the critically ill patient. The day-to-day variation in resting energy expenditure (REE) was studied over a 3-5-day period in 17 postoperative mechanically ventilated critically ill patients to gain insight as to how often caloric intake should be reassessed, whether changes observed over 3-5 days are of sufficient magnitude to make frequent adjustments in caloric intake, and what factors are associated with large alterations in metabolic rate. REE was measured daily for 3-5 days, and the percent variation in REE [(highest REE--lowest daily REE)/(lowest daily REE) x 100] calculated. The variation ranged from 4 to 56%, and on further analysis two distinct groups were identified, one with a mean variation of 12 +/- 4% (SD) (range 4-18%) and the other with a mean variation of 46 +/- 8% (range 37-56%). The former group was clinically stable, whereas the latter was not. Clinically stable patients need less frequent measurements than those who are more ill, but when designing a nutritional regimen for them, at least 20-25% should be added to the REE, 15% to account for day-to-day variation and 5-10% for activity.
authors.affiliation: Department of Anesthesiology, College of Physicians and Surgeons, Columbia University, New York, New York.
authors.forename: C
authors.initials: C
authors.lastname: Weissman
authors.forename: M
authors.initials: M
authors.lastname: Kemper
authors.forename: A I
authors.initials: AI
authors.lastname: Hyman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003422:Critical Care; D004734:Energy Metabolism; D006801:Humans; D008875:Middle Aged; D009747:Nutritional Physiological Phenomena; D010101:Oxygen Consumption; D011184:Postoperative Period; D012121:Respiration, Artificial