Læknablaðið - 15.07.2009, Blaðsíða 17

FRÆÐIGREINAR
RANNSÓKN
17. Branson R. The measurement of energy expenditure:
instrumentation, practical considerations, and clinical
application. Respir Care 1990; 35: 640-56; discussion 56-59.
18. Villet S, Chiolero RL, Bollmann MD, et al. Negative impact
of hypocaloric feeding and energy balance on clinical
outcome in ICU patients. Clin Nutr 2005; 24:502-9.
19. O'Leary-Kelley CM, Puntillo KA, Barr J, Stotts N, Douglas
MK. Nutritional adequacy in patients receiving mechanical
ventilation who are fed enterally. Am J Crit Care 2005; 14:
222-31.
20. Plank LD, Hill GL. Energy balance in critical illness. Proc
Nutr Soc 2003; 62: 545-52.
21. Chiolero R, Revelly JP, Tappy L. Energy metabolism in sepsis
and injury. Nutrition 1997; 13(9 Suppl):45S-51S.
22. Heyland DK, Dhaliwal R, Drover JW, Gramlich L, Dodek P.
Canadian clinical practice guidelines for nutrition support
in mechanically ventilated, critically ill adult patients. JPEN
J Parenter Enteral Nutr 2003; 27:355-73.
23. Rubinson L, Diette GB, Song X, Brower RG, Krishnan
JA. Low caioric intake is associated with nosocomial
bloodstream infections in patients in the medical intensive
care unit. Crit Care Med 2004; 32: 350-7.
24. van den Berghe G, Wouters P, Weekers F, et al. Intensive
insulin therapy in the critically ill patients. N Engl J Med
2001; 345:1359-67.
25. Board. NAoSIoMFaN. Dietary Reference Intakes for Energy,
Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein,
and Amino Acids (Macronutrients) 2005.
26. Hoffer LJ. Protein and energy provision in critical illness.
Am J Clin Nutr 2003; 78: 906-11.
27. Griffiths RD, Jones C, Palmer TE. Six-month outcome
of critically ill patients given glutamine-supplemented
parenteral nutrition. Nutrition 1997; 13: 295-302.
Viðauki
a) Jafna notuð við útreikning á orkunotkun sjúklings (Resting energy expenditure- REE)-1
Hvíldarorkunotkun (REE) = 5,50xVO2+ 1,76VCO? + 1,99UN
Þar sem V02 er súrefnisnotkun (ml/mín), VC02 koldíoxíðframleiðsla (ml/mín) og UN er niturútskilnaður í þvagi á sólarhring. Stærðirnar
V02 og VC02 fást með mælingum á inn- og útöndunarlofti en UN með niturmælingu í þvagi. Þáttur niturs er fremur lítiil í jöfnunni og
gefur í mesta lagi 4% skekkju ef niturútskilnaður er áætlaður og var það gert í þessari rannsókn í samræmi við athuganir annarra.
b) Öndunarstuðull (Respiratory quotient; RQ) fæst með eftirfarandi jöfnu:1
RQ = VC02 / V02.
c) Harris-Benedict-jafnan:
Ýmsar jöfnur hafa verið notaðar til að áætla orkunotkun eintaklinga en algengast er að styðjast við Harris-Benedict-jöfnuna sem var
leidd út frá mælingum á heilbrigðum einstaklingum árið 1919 og tekur mið af hæð (H), þyngd (Þ), kyni og aldri (A):2
1. Orkunotkun karla = 66,45 + 13.75Þ + 5,00H - 6,78A
2. Orkunotkun kvenna = 655,1 + 9,56Þ + 1,85H - 4,68A
Þegar jafnan hefur verið notuð á gjörgæsludeildum til að ákvarða orkunotkun sjúklinga hefur hún oft verið uppfærð með því að
margfalda útkomu hennar með ákveðnum streitustuðli. Með þessum stuðli má taka inn í útreikningana efnaskiptahækkun sem er
talin verða í veikum og slösuðum sjúklingum. Ýmsir streitustuðlar hafa verið notaðir en í þessari rannsókn var notaður stuðull 1 3
(30% aukning á efnaskiptahraða).3
1. Fung EB. Estimating energy expenditure in critically ill adults and children. AACN Clin Issues 2000; 11: 480-97.
2. Harris J, Benedict F. A biometric study of basal metabolism in man. 1919; 297.
3. Reid CL. Poor agreement between continuous measurements of energy expenditure and routinely used prediction
equations in intensive care unit patients. Clin Nutr 2007; 26: 649-57.
Energy expenditure and nutritional support in intensive care patients
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Study objectives: Nutritiona! support of ICU patients
is usually guided by estimations of their caloric needs.
However, recent studies have shown that energy
expenditure (EE) of critically íll patients is not as high as
previously thought. The goal of this study was to measure
EE in ICU patients, compare it with estimated EE and
evaluate nutritional support.
Methods: Energy expenditure was measured with indirect
calorimetry in a broad group of ICU patients requiring
mechanical ventilation >48hours. In comparison EE was
estimated with the Harris-Benedict equation. Nutritional
support during ICU stay was registered.
Results: Mean measured EE of 56 patients was 1820
±419 kcal/day or 22 kcal/kg/day. The Harris- Benedict
equation underestimated EE by 11%, but adding a stress
factor resulted in 15% overestimation. Mean nutritional
support was 1175 ± 442 kcal/day or 67% of EE. The
energy deficit was greatest during the first week of ICU
stay. Mean protein administration was 0,44 g/kg/day.
Conclusion: Measured EE of ICU patients was less
than nutritional support recommended by international
guidelines. These results are in accordance with recent
studies. Nutritional support was only 67% of measured
energy expenditure and protein content less than
recommended. Further studies are needed as it has not be
shown how this might influence outcome.
Kristinsson B, Sigvaldason K, Karason S.
Energy expenditure and nutritional support in intensive care patients. Icel Med J 2009; 95: 491-7
Key words: energy expenditure, indirect calorimetry, Intensive care unit, nutrition, Harris-Benedict equation.
Correspondence: Bjarki Kristinsson, bjarkiknSgmail.com
Barst: 22. desember 2008, - samþykkt til birtingar: 14. maí 2009
LÆKNAblaðið 2009/95 497