Eur Surg (2011) 43/1: 5–6 europeansurgeryACA Acta Chirurgica Austriaca

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DOI 10.1007/s10353-011-0586-x© Springer-Verlag 2011

Editorial: Nutritional support of critically ill or injuredpatients: do it early and do it rightR. Latifi

Dear Readers,

Nutritional support of critically ill or injured pa-tients has undergone significant advances in the last fewdecades. These advances are the direct result of ourgrowing scientific progress and increased knowledge ofthe biology and biochemistry of key nutrient changesinduced by injury, sepsis, and other critical illnesses,both in adults and in children. As this knowledge hasincreased, the science of nutritional support has becomemore disease-based. Depending on the individual pa-tient’s metabolic needs, key nutrients are replenished oradded in larger amounts to supplement specific deficien-cies or to simply prevent further deterioration and clinicalconsequences.

Thus, in recent years, the vocabulary and the practiceof nutritional support have significantly changed. In thisnew nutritional support era, nutripharmaceutics has be-comeanintegralpartofcritically illor injuredpatients’ care.The question is no longer whether or not such patientsshould be fed, but rather when and what to feed them.

The benefit of early institution of enteral nutrition(EN) or total parenteral nutrition (TPN) in the overall careof such patients has now been well established. After acritical illness or injury, the patient’s energy and overallmetabolic requirements greatly increase, in order to sus-tain the increased metabolism and the process of woundrepair. Similarly, protein requirements also greatly in-crease, in order to provide a substrate for protein synthe-sis. Provision of calories and nitrogen in a ratio of 150:1has been shown to be most efficacious in achieving apositive balance. However, it is not yet completely un-derstood whether improved nitrogen balance in patientson TPN is achieved by an increase in protein synthesis orby a decrease in protein (muscle) catabolism. Still, earlyEN or TPN is clearly associated with improved nitrogenbalance. Given current evidence derived from random-ized prospective controlled trials, early provision of nu-trition in critically ill or injured patients is now a Level Irecommendation.

In general, the optimal route for providing nutritionin critically ill or injured patients has been established:

the gastrointestinal tract, whenever possible. But if thepatient will not receive all needed nutrient substrates andcalories enterally, then nutrition should be provided orsupplemented parenterally.

Because of the recent advances in identifying andrecognizing fundamental metabolic changes in key nu-trient substrates in critically ill or injured patients, nutri-tional formulas are being designed to overcome thosechanges. For example, enteral immune-enhancing for-mulas (IEFs) have been shown to improve immune re-sponse in laboratory animals as well as in critically ill orinjured patients. IEFs contain increased amounts of pep-tides; arginine; glutamine; vitamins E, A, and C; nucleo-tides and nucleosides; branched-chain amino acids(BCAAs); and omega-3 fatty acids. It is suggested thatthose key nutrients, if given early and in doses higher thantypically recommended, can modulate and affect a vari-ety of inflammatory, metabolic, and immune processes.Nonetheless, what type of nutritional formula to useremains controversial. The controversy often stems notfrom the scientific evidence or the lack of it, but insteadfrom economic and political factors, including the dy-namics of purchasing nutritional formulas and obtainingthe best contracts between hospitals and industry.

Although the biology of nutritional support is nowmuch better understood, we far from know all we need toknow in this complex field. But we do know that aminoacids and other special nutrients are a key component ofnutritional and metabolic management. To effectivelypractice medicine, we need a working knowledge of themultiple and complex functions of amino acids [1]. Be-cause derangements in amino acid metabolism are com-mon in pathologic states and are detrimental to optimalmetabolic function, we must reverse such derangements(and the physiologic alterations they cause) by providingoptimal nutritional support. We cannot simply ignore themetabolic changes of the amino acid pool and milieuanymore, and we must take them into account whencreating new formulations of nutrient formulas, whetherenteral or parenteral. The use of specific IEFs with aminoacids in higher pharmacologic doses, and in specialcombinations and ratios, is beneficial to critically ill orinjured patients [2].

Standardization – of the methods for studyingnutritional support, of the clinical criteria for using spe-cialized nutrient substrates (such as those fortified withBCAAs), of patient selection for EN and TPN, and of other

Correspondence: Rifat Latifi, MD, FACS, Professor of Surgery, Divi-sion of Trauma, Critical Care and Emergency Surgery, Department ofSurgery, University of Arizona, 1501 N Campbell Avenue, Tucson,Arizona 85724, USA.Fax: þ1-520-626-5016E-mail: latifi@surgery.arizona.edu

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variables – is already adding to the evidence for nutri-tional support and will help resolve the contradictoryfindings of clinical studies. The main difficulties in ob-taining meaningful evidence-based data include the dif-ferent nutrient substrates used, the various criteria forpatient selection, and the array of study endpoints. In thefuture, we should strive to use genetically altered nutrientsubstrates that will mimic, or even better, substitute forthe perfect nutrient substrates for most critically ill orinjured patients, thereby exactly correcting the cellularimbalances caused by the illness, sepsis, or injury. Wemust reverse the pathophysiologic derangements in ami-no acid metabolism, nucleotides, vitamins, and traceelements by ensuring optimal nutritional support withIEFs. Ideally, IEFs should contain high doses of arginine,glutamine, taurine, BCAAs, nucleotides and nucleosides,omega-3 fatty acids, zinc, selenium, and vitamins E, A,and C. Such IEFs need to be inexpensive and available inenteral, as well as parenteral, form. Finally, nutritionalsupport should be an integral part of critical care basedon current evidence-based medicine and guidelines [3].

R. Latifi

Acknowledgment

The guest editor and author would like to express theirgratitude to Mary Knatterud, Ph.D. for her editorial assis-tance on this special issue.

Conflict of interest

The author declares that there is no conflict of interest.

References

[1] Latifi R, Dudrick SJ (eds). The biology and practice of currentnutrition support. 2nd ed. Georgetown, Texas: Landes Biosci-ence; 2003.

[2] Latifi R (ed.). Amino acids in critically ill and cancer patients.Georgetown, Texas: RG Landes Publishing Company and CRCPress; 1994.

[3] McClave SA, Martindale RG, Vanek VW, et al. Guidelines forthe Provision and Assessment of Nutrition Support Therapyin the Adult Critically Ill Patient: Society of Critical CareMedicine (SCCM) and American Society for Parenteral andEnteral Nutrition (A.S.P.E.N.). J Parenter Enteral Nutr 2009;33:277–316.

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