Background: Aging adversely affects nitrogen accretion during health, but its effect during critical illness is unknown. Nitrogen balance (NB) response to varying protein intakes was compared between critically ill, older and younger patients. Methods: Adult patients admitted to the trauma intensive care unit, given enteral or parenteral nutrition, and who had a NB determination within 5–14 days after injury were evaluated. Patients with renal or hepatic disease were excluded. Patients were categorized as older (≥60 years) or younger (18–59 years of age). Data are given as mean ± SD or median [interquartile range]. Results: Fifty-four older (69 [65, 77] years) and 195 younger (35 [27, 47] years) patients were evaluated. NB was blunted for the older patients with an observed trending improvement in NB from −13.5 ± 5.5 to −5.6 ± 8.8 g/d (P = NS) noted at 1.5−1.99 g/kg/d. NB improved from −22.2 ± 8.2 to −11.8 ± 9.9 g/d (P = .05) at 1–1.49 g/kg/d and modestly thereafter for each 0.5-g/kg/d increase in protein intake for the younger patients. Serum urea nitrogen concentration during the NB was highly variable but overall greater for the older patients (20 [14, 33] vs 15 [10, 20] mg/dL, P = .001). Conclusions: Improvement in nitrogen accretion was blunted at lower protein intakes in critically ill, older patients compared with younger patients. Individualization of protein intake is warranted.
DickersonRNPittsSLMaishGOIII. A reappraisal of nitrogen requirements for patients with critical illness and trauma. J Trauma Acute Care Surg. 2012;73:549-557.
2.
ShawJHWolfeRR. An integrated analysis of glucose, fat, and protein metabolism in severely traumatized patients: studies in the basal state and the response to total parenteral nutrition. Ann Surg. 1989;209:63-72.
3.
DoigGSHeighesPTSimpsonFSweetmanEA. Early enteral nutrition reduces mortality in trauma patients requiring intensive care: a meta-analysis of randomised controlled trials. Injury. 2011;42:50-56.
4.
RappRPYoungBTwymanD. The favorable effect of early parenteral feeding on survival in head-injured patients. J Neurosurg. 1983;58:906-912.
5.
SacksGSBrownROTeagueDDickersonRNTolleyEAKudskKA. Early nutrition support modifies immune function in patients sustaining severe head injury. JPEN J Parenter Enteral Nutr. 1995;19:387-392.
6.
GuilletCProd’hommeMBalageM. Impaired anabolic response of muscle protein synthesis is associated with S6K1 dysregulation in elderly humans. FASEB J. 2004;18:1586-1587.
7.
VolpiEMittendorferBRasmussenBBWolfeRR. The response of muscle protein anabolism to combined hyperaminoacidemia and glucose-induced hyperinsulinemia is impaired in the elderly. J Clin Endo Metab. 2000;85:4481-4490.
8.
KoopmanRWalrandSBeelenM. Dietary protein digestion and absorption rates and the subsequent postprandial muscle protein synthetic response do not differ between young and elderly men. J Nutr. 2009;139:1707-1713.
9.
OstermannMChangR. The RIFLE criteria: are the foundations robust?Crit Care Med. 2007;35:2669-2670.
DickersonRNMedlingTLSmithAC. Hypocaloric, high-protein nutrition therapy in older vs younger critically ill patients with obesity. JPEN J Parenter Enteral Nutr. 2013;37:342-351.
14.
KatsanosCSKobayashiHSheffield-MooreMAarslandAWolfeRR. Aging is associated with diminished accretion of muscle proteins after the ingestion of a small bolus of essential amino acids. Am J Clin Nutr. 2005;82:1065-1073.
15.
RasmussenBBFujitaSWolfeRR. Insulin resistance of muscle protein metabolism in aging. FASEB J. 2006;20:768-769.
16.
Iannuzzi-SucichMPrestwoodKMKennyAM. Prevalence of sarcopenia and predictors of skeletal muscle mass in healthy, older men and women. J Gerontol. 2002;57:M772-M777.
17.
BakerSPO’NeillBHaddonWJrLongWB. The injury severity score: a method for describing patients with multiple injuries and evaluating emergency care. J Trauma. 1974;14:187-196.
18.
AbrahamEMatthayMADinarelloCA. Consensus conference definitions for sepsis, septic shock, acute lung injury, and acute respiratory distress syndrome: time for a reevaluation. Crit Care Med. 2000;28:232-235.
19.
HarrisJABenedictFB. A Biometric Study of Basal Metabolism in Man. Washington, DC: Carnegie Institution of Washington; 1919. Report No. 279.
20.
MelzerKLaurie KarsegardVGentonLKossovskyMPKayserBPichardC. Comparison of equations for estimating resting metabolic rate in healthy subjects over 70 years of age. Clin Nutr. 2007;26:498-505.
21.
NeelemaatFvan Bokhorst-de van der SchuerenMAThijsASeidellJCWeijsPJ. Resting energy expenditure in malnourished older patients at hospital admission and three months after discharge: predictive equations versus measurements. Clin Nutr. 2012;31:958-966.
22.
DickersonRNMitchellJNMorganLM. Disparate response to metoclopramide therapy for gastric feeding intolerance in trauma patients with and without traumatic brain injury. JPEN J Parenter Enteral Nutr. 2009;33:646-655.
23.
DickersonRNSwiggartCEMorganLM. Safety and efficacy of a graduated intravenous insulin infusion protocol in critically ill trauma patients receiving specialized nutritional support. Nutrition. 2008;24:536-545.
24.
DickersonRNWilsonVCMaishGOIIICroceMAMinardGBrownRO. Transitional NPH insulin therapy for critically ill patients receiving continuous enteral nutrition and intravenous regular human insulin. JPEN J Parenter Enteral Nutr. 2013;37:506-515.
25.
DickersonRNMasonDLCroceMAMinardGBrownRO. Evaluation of an artificial neural network to predict urea nitrogen appearance for critically ill multiple-trauma patients. JPEN J Parenter Enteral Nutr. 2005;29:429-435.
26.
CockcroftDWGaultMH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16:31-41.
27.
BoyceEGDickersonRNCooneyGFGibsonGAMullenJL. Creatinine clearance estimation in protein-malnourished patients. Clin Pharm. 1989;8:721-726.
28.
MinvilleVAsehnouneKRuizS. Increased creatinine clearance in polytrauma patients with normal serum creatinine: a retrospective observational study. Crit Care. 2011;15:R49.
DickersonRNTidwellACMinardGCroceMABrownRO. Predicting total urinary nitrogen excretion from urinary urea nitrogen excretion in multiple-trauma patients receiving specialized nutritional support. Nutrition. 2005;21:332-338.
31.
MackenzieTAClarkNGBistrianBRFlattJPHallowellEMBlackburnGL. A simple method for estimating nitrogen balance in hospitalized patients: a review and supporting data for a previously proposed technique. J Am Coll Nutr. 1985;4:575-581.
32.
BlumenkrantzMJKoppleJDGutmanRA. Methods for assessing nutritional status of patients with renal failure. Am J Clin Nutr. 1980;33:1567-1585.
33.
MorganLMDickersonRNAlexanderKHBrownROMinardG. Factors causing interrupted delivery of enteral nutrition in trauma intensive care unit patients. Nutr Clin Pract. 2004;19:511-517.
34.
WalrandSBoirieY. Optimizing protein intake in aging. Curr Opin Clin Nutr Metab Care. 2005;8:89-94.
35.
BosCBenamouzigRBruhatA. Short-term protein and energy supplementation activates nitrogen kinetics and accretion in poorly nourished elderly subjects. Am J Clin Nutr. 2000;71:1129-1137.
36.
VolpiEFerrandoAAYeckelCWTiptonKDWolfeRR. Exogenous amino acids stimulate net muscle protein synthesis in the elderly. J Clin Invest. 1998;101:2000-2007.
37.
VolpiEMittendorferBWolfSEWolfeRR. Oral amino acids stimulate muscle protein anabolism in the elderly despite higher first-pass splanchnic extraction. Am J Physiol. 1999;277:E513-E520.
38.
CampbellWWCrimMCDallalGEYoungVREvansWJ. Increased protein requirements in elderly people: new data and retrospective reassessments. Am J Clin Nutr. 1994;60:501-509.
39.
FAO/WHO/UNU. Energy and protein requirements: report of a joint FAO/WHO/UNU Expert Consultation. WHO Tech Rep Series. 1985;724:1-206.
40.
BirkhahnRHLongCLFitkinDJeevanandamMBlakemoreWS. Whole-body protein metabolism due to trauma in man as estimated by L-[15N]alanine. Am J Physiol. 1981;241:E64-E71.
41.
CarlottiAPBohnDMatsunoAKPastiDMGowrishankarMHalperinML. Indicators of lean body mass catabolism: emphasis on the creatinine excretion rate. QJM. 2008;101:197-205.
42.
SchillerWRLongCLBlakemoreWS. Creatinine and nitrogen excretion in seriously ill and injured patients. Surg Gynecol Obstet. 1979;149:561-566.
43.
WolfeRRMillerSLMillerKB. Optimal protein intake in the elderly. Clin Nutr. 2008;27:675-684.
44.
FliserDZeierMNowackRRitzE. Renal functional reserve in healthy elderly subjects. J Am Soc Nephrol. 1993;3:1371-1377.
45.
ManattMWGarciaPA. Nitrogen balance: concepts and techniques. In: NissenS, ed. Modern Methods in Protein Nutrition and Metabolism. San Diego, CA: Academic Press; 1992:9-66.
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