CritCareNursJ.2018August;11(3):e87976.                                                                       doi: 10.5812/ccn.87976.
                Publishedonline2019January28.                                                                                        ReviewArticle
                ComparisonofEnteralandParenteralNutritioninPatientsAdmitted
                totheICU:ANarrativeReviewStudy
                MahdiPoornazari            1, SomayehMohammadi                 1, MostafaRoshanzadeh              2 andAliTajabadi          3, *
                1NursingFacultyof Broujen,Shahr-e-Kord,Iran
                2ShahidBeheshtiMedicalEthicsandLawCenter,Tehran,Iran
                3ParamedicalFaculty,SabzevarUniversityof MedicalSciences,Sabzevar,Iran
                *Correspondingauthor:Ph.DStudent,ParamedicalFaculty,SabzevarUniversityof MedicalSciences,Sabzevar,Iran.Email:alitaj58@yahoo.com
                Received2018December19;Revised2018December31;Accepted2019January05.
                  Abstract
                  Context: Nutrition support is part of the standard care in the intensive care unit. There is a paradox in the use of enteral and
                  parenteralnutritionmethodsinICUpatients.
                  Objectives: Theaimof thisstudywastocomparetheeffectsof enteralandparenteralnutritionmethodsinpatientsadmittedto
                  theICU.
                  DataSources: Thisarticleisanarrativereview. Atotalof 619articles, wereextractedduringtheyearsof 2000-2018,onnutrition
                  methodsinICUpatients, withkeywordsenteralnutrition, parenteral nutrition, and nutrition in critical patients in databases of
                  internal (SID, Iran Medex, Medlib) and external publications (PubMed, Scopus, Web of Science, Google Scholar); finally, 19 articles
                  wereanalyzed.
                  Results: Enteraladministrationreducedtheassociatedinfectiousmorbidity,hospitalizationtime,mortality,costs,non-infectious
                  complications,multipleorganfailure,systemicinfections,localsepticcomplications,andtheneedforsurgery. Italsocausesearly
                  returningof intestinal movements, faster preoperative weight gain, easier fluid and electrolyte management, reduction of hyper
                  metabolic responses, more complete nutrition, preservation of the gastrointestinal mucosa, and the ability to complete the pro-
                  grambythepatient. Parenteralnutritionincreasesinfectiouscomplications,hyperglycemia,coagulationdisordersandduration
                  of hospitalstay,aswellaseffectsoninvasiveventilation.
                  Conclusions: Enteralnutritionissaferandlesscomplicated. Byimprovingtheawarenessof careersthrougheducation,patients
                  canbeimprovedfaster.
                  Keywords:EnteralNutrition,IntensiveCareUnit,ParenteralNutrition
                1. Context                                                           malnutrition in advanced countries (5). Most patients in
                                                                                     theintensivecareunit(ICU)areunabletofulfilltheirown
                    Forovertwodecades,variousstudieshaveshownthat                    nutritional needs; thus, they are at a high risk in develop-
                malnutrition is common in hospitalized patients (1). It              ingenergydeficit. Theprevalenceof malnutritionis44% -
                shouldbeacknowledgedthatthelackofadequateappetite                    88% intheICU(6).Metabolicchangesinresponsetostress
                duetoillness, increased nutrient intake, and nutrient ab-            lead to increased protein catabolism, a certain reduction
                sorptioninpatientsareamongthemostimportantfactors                    in body mass, and an increase in the incidence of compli-
                in the incidence of malnutrition intensification in hos-              cations,especiallyinfectionsandinappropriateoutcomes
                pitalized patients (2). Medical treatment and nutritional            in the patient. Malnutrition in ICU patients, due to weak-
                nursing care are important for patients’ nutritional con-            nessoftheimmunesystemandtheuseofventilator,leads
                dition and may prevent malnutrition. The nurses’ skills              to prolonged dependence on ventilator and increased in-
                and knowledge are crucial when creating secure care for              fectiousmorbidityandmortality(7).
                the patient. This places nurses in a unique position to se-               Nutrition support has been recognized as essential
                curegoodnutritionalnursingcare(3).Severalstudieshave                 therapiesformaintainingtheactivemassofthebody,bal-
                shown that in patients who are admitted, malnutrition                anceintheimmunesystem,andreducingmetaboliccom-
                variesfrom30% to87% (4).Accordingtoexistingresearch,                 plications(8).Thefirstattemptinnourishingpatientswho
                about50% of patients admitted to hospitals are at risk of            were not able to eat was in the late 19th century; in 1872
                Copyright© 2019,CriticalCareNursing.Thisisanopen-accessarticledistributedunderthetermsoftheCreativeCommonsAttribution-NonCommercial4.0International
                License(http://creativecommons.org/licenses/by-nc/4.0/)whichpermitscopyandredistributethematerialjustinnoncommercialusages,providedtheoriginalworkis
                properlycited.
                                                                          PoornazariMetal.
                   a person called Clouston used a method for the intragas-         fectious complications, most likely due to hyper alimen-
                   tric tube and began infusing milk, eggs, alcohol, sugar,         tation and hyperglycemia, as consistently shown in ear-
                   andjelly. At the beginning of the 20th century the diges-        lier meta-analyses.   These clinical data have translated
                   tivetracttechniqueswereimproved,andsince1937,Elman               intoawidespreadconsensusamongcurrentinternational
                   performedintravenousinfusionofcaseinhydrolyzed,and               guideline recommendations and expert opinions where
                   thenothermaterialssuchasaminoacids,hypertonicglu-                theenteralrouteispreferredincriticallyillpatientswith-
                   cose, and nitrogen were injected into the central vein (9).      out a contraindication to EN (19). Recently, Harvey and
                   Since 1960, parenteral nutrition was accepted in the care        coworkers conducted the largest randomized controlled
                   of patients with chronic non-functional gastrointestinal         trial (RCT) to date with respect to the effect of the route
                   tract(10).                                                       of nutritionontheoutcomeof criticallyilladultpatients.
                       There is a significant improvement in the care of pa-         In this pragmatic RCT involving 2388 patients, neither a
                   tients receiving intestinal and venous nutrition; however,       significantdifferenceinmortalitynorinfectiouscomplica-
                   theeffectsandconsequencesofthesemethodsarestillnot                tionswasfoundbetweenthepatientsreceivingtotalPNor
                   clear. Further studies are needed to understand the im-          ENwithin36hoursafteradmissionanduptoamaximum
                   pactofthesetwomethodsandtheircomplications(11).Itis              of five days. These results have challenged the paradigm
                   difficulttofindameaningfulcomparisonbetweenenteral                  thatENissuperiortoPNwithregardtoclinicaloutcomes
                   and parenteral nutrition. There is a physiological differ-        incriticalillness(20).
                   ence between these two methods of nutrition. Appropri-               Thedatafromthereviewofnutritionalmethodsofin-
                   ate nutritional clinical outcomes include mortality, mor-        tensive care units indicate that they are not properly ob-
                   bidity,qualityoflife,andcarecoststhatrequirelargestud-           servingtheindicationsandcontraindicatingtheadminis-
                   ies. On the other hand, it is easy to obtain some criteria,      tration of enteral and parenteral nutrition, and it seems
                   suchasdeterminingtheserumproteinoranthropometric                 thattheyarenottakingintoaccountthecomplicationsof
                   measure,however,thesearenotthetruecriteriaforachiev-             eachof these methods, especially the parenteral method;
                   ingnutritionaladequacyinpatients;theycanonlybeused               the patient’s condition is prioritized care and treatment.
                   aspredictivefactors(12).                                         The question being asked is which nutritional method is
                       The use of enteral method was reported as 92% - 93%          moreeffectiveinpatientsadmittedtotheICU?Toanswer
                   andparenteralmethodtobebetween12% -71% inpatients                this question, we examinedtheindications, contraindica-
                   admitted in the ICU. Several factors are influence on the         tions, complications, and the rates of each of these meth-
                   choice of enteral and parenteral methods, one of which           ods.
                   is to estimate the usefulness of the nutritional method
                   andits harm (13). In many articles, the use of the enteral       2. Objectives
                   method has been more beneficial than parenteral; how-
                   ever, the proof of such a claim requires studies based on            Theaimofthisstudywastocomparetheeffectsofen-
                   evidenceaswellasinformationregardingthesideeffects                teral and parenteral nutrition methodsinpatientsadmit-
                   of each of these nutritional methods (14). Safety interven-      tedtotheICU.
                   tionshavereducedtherateofcentralvenouscathetercon-
                   tamination; the acceptable level is now zero in hospital-
                   ized patients (15). This may improve the safety of intra-        3. DataSources
                   venous nutrition due to the fact that the increase in in-
                   fection in this methodisthemostcommondifferencebe-                    Thedesignof this study is a narrative review. Articles
                   tweenthetwomethodsofnutrition(16).                               weresearchedinthefieldofnutritionalmethodsinICUpa-
                       Usingtheenteralrouteisconsideredtobemorephysi-               tients with keywords (enteral nutrition, parenteral nutri-
                   ologic, providing nutritional and various non-nutritional        tion, nutrition in critically patient), in databases SID, Iran-
                   benefits including maintenance of structural and func-            Medex, Medlib, as well as publications such as PubMed,
                   tional gut integrity as well as preserving intestinal micro-     Scopus,WebofScience,andGoogleScholar. Theinclusion
                   bial diversity (17). The disadvantage of enteral nutrition       criteria included: existence of a study in the field of nutri-
                   (EN) is related to a potential lower nutritional adequacy        tion of patients admitted to the ICU, research and review
                   particularly in the acute disease phase and in the pres-         studies, consideration of time constraints (2000 - 2018),
                   enceof gastrointestinal dysfunction (18). In contrast, par-      published articles in journals in or outside the country,
                   enteral nutrition (PN) may better secure the intended nu-        andthefocusofthestudybeingonthecomparisonofen-
                   tritional intake; however, it is associated with more in-        teral nutrition withparenteral. Theexclusioncriteriaalso
                   2                                                                                         CritCareNursJ.2018;11(3):e87976.
                                                                      PoornazariMetal.
               includednon-EnglishandPersianlanguage,lackof access              those who receive catecholamine (such as epinephrine,
               to the full text of the article, abstracts of congresses and     phenylephrine and dopamine) need to have these agents
               seminars, a letter to the editor, a brief report, as well as a   to maintain hemodynamic stability. Food should be in-
               case report. Some articles searched in several phases and        fusedintothesmallintestine. Inaddition,inICUpatients,
               deleted.Inthewidersearch,215000articleswereobtained.             if thereisariskofaspiration,orintolerancetostomachnu-
               Subsequently,6160articleswereselectedrelatedtothenu-             trition, it should be put in ways to get the enteral into the
               tritioninhospitalizedpatients,andthen,619articleswere            smallintestine(26).Enteralnutritionmethodisalsoapre-
               obtainedbyfocusingonthenutritionofpatientsadmitted               ferred nutritional method in ICU patients with acute and
               totheICUandtakingintoaccounttheinclusionandexclu-                chronicliverdisease.Patientswhohaveliverfailureshould
               sioncriteria. Atotalof99articlesremainedbylimitingthe            avoidproteinrestriction.Thepatientswhoareillandhave
               searchtothestudypurposeandconsideringtheoverlapof                acutepancreatitisshouldbefittedagastrointestinaltract
               articles,whichultimatelyresultedin19fulltextarticles.In          andfedmorequicklybyfluidregeneration.Thesepatients
               order to evaluate the quality of the collected articles, two     canbefedbythemethodoffeedingtheenteralstomachor
               researchersreviewedthearticlesintermsoftitle,abstract,           jejunum(27).
               introduction,method,results,anddiscussion(Figure1).                  Of course, there are some limitations to the meth-
                                                                                odsof feeding enteral. Absolute contraindications for us-
               4. Results                                                       ingtheenteralmethodinclude: Illness-relatedIleus, mul-
                                                                                tiple trauma associated with retroperitoneal hematoma,
                   The reviewed articles in this study were divided into        peritonitis, intestinal obstruction, active gastrointestinal
               avariety of studies (four clinical trials, two meta-analysis,    hemorrhage, hemodynamic instability, and intestinal is-
               three reviews, four prospectives, one retrospective, four        chemia. Relative contraindications include diverticulum
               cross-sectional descriptives, and one guideline). The re-        abscesses,earlystagesof smallintestinesyndrome,severe
               viewedstudiespresenteddifferentresultsandsuggestions              malabsorption, small intestinal fistulas, and the need for
               regarding the priority of using two methods of nutrition         earlynutritionsupportisnotfeasibleforfullfeeding(28).
               for patients who are hospitalized in the ICU, according to           Enteralnutritionhassideeffectslikeanyotherinvasive
               thetypeof illness and conditions of the patient. Patients’       procedure. Complications of this nutritional method are
               whocannot have more than three days of oral nutrition            dividedintofourcategories,includingmechanicaleffects
               mustbenutritionallysupported(21).Intestinalnutritional           (esophageal tracheal fistula, tube displacement and dis-
               support (enteral) should be initiated in ICU patients that       charge,tubeobstruction,foodleak,andpulmonaryaspira-
               are unable to receive food voluntarily, should also clearly      tion),metabolic(suchashyperosmolaritis,hyperglycemia
               state the ultimate goal of using it, and measured the en-        and hypoglycemia, electrolyte imbalance blood, refeed-
               ergy requirements clearly at the start. Efforts should be         ing syndrome, hypercapnia and hypertonic depression),
               madetoprovidemorethan50% -65% ofthecalorietarget                 infections (sinusitis, otitis, pneumonia, necrotic peritoni-
               inordertoreachtheclinicalgoalsofenteralnutritiondur-             tis, and enteritis), and digestive complications (diarrhea,
               ingthefirstweekofhospitalization(22).                             constipation, vomiting, abdominal distension and hep-
                   Theuseofenteralnutritionmethodmustbefittedinto                atomegaly)(29).
               thenutritiontubeintheICUwithinthefirst24to48hours                     Another method is parenteral for feeding patients in
               of admission, and should be started if the patient has in-       theICU,whoseindicationsaregiveninTable1.
               testinal sounds as well as gas and stool excretion, to re-           Theuseofparenteralnutritionisconsiderediftheuse
               ducethefoodintolerance,theriskofdysfunctionoftheim-              of enteral nutrition is not available or not possible in the
               munedefenses, and infections. Enteral nutrition should           first seven days of admission to the ICU, the patient has a
               provide 25 - 30 kcal/kg body weight per day (23). Indica-        good health status before illness, and the patient has no
               tions for using an enteral nutritional method include: (1)       malnutrition of protein and calories. However, the onset
               in cases nutrition oral contraindication; (2) inability to       of parenteralattheadministrationtimeisallowedifthere
               meet nutritional needs of the patients by oral nutrition;        is evidence of malnutrition of calorie protein at the time
               and (3) the need for supportive nutrition due to reduced         ofadmissionandthelackofavailablesupplyofenteralnu-
               absorption(24).                                                  trition. In addition,if thepatientislikelytohavegastroin-
                   Enteral nutrition is prescribed in patients who are          testinal surgery and it is not possible to feed the enteral,
               pronetodigestivedisorders,sepsis,hypotension,andthen             parenteral nutrition should be started under certain con-
               anincreasedriskof ischemicinjuryandre-perfusion(25).             ditions(30).
               Patients with hypotension (MAP < 60 mmHg), especially                In the malnourished, parenteral nutrition should be-
               CritCareNursJ.2018;11(3):e87976.                                                                                            3
                                                                                      PoornazariMetal.
                        Search in different databases by keywords (215000)
                                                                                   Removal of unrelated articles with nutrition in admitted patients (208840)
                        Review articles in the field of nutrition in the icu (619)
                                                          
                                                                                  Deleted articles according to purpose and overlaping (520)  
                        Review the fulltext article related to the to pic (19)
                      Figure1.Reviewarticlesanddatacollectionprocess
                      Table1.ParenteralNutritionIndications
                        IndicationofParenteralNutrition                                         RelatedStudies
                        Inabilitytoabsorbenoughdigestivenutrition(largeintestinalresection,     Pontes-Arrudaetal.(30),“Influenceofparenteralnutritiondeliverysystemonthe
                        shortintestinalsyndrome,enteritiscausedbyradiotherapy,severe            developmentofbloodstreaminfectionsincriticallyillpatients:Aninternational,
                        diarrhea).                                                              multicenter,prospective,open-label,controlledstudy”
                        Completeorfalseintestinalobstruction,acuteabdomen,orileusand            Mundietal.(31),“Managementofparenteralnutritioninhospitalizedadult
                        persistentdigestivehemorrhage.                                          patients”
                        Extremecatabolismwhenthedigestivesystemisnotusableforfiveto              Preiseretal. (32),“Metabolicandnutritionalsupportof criticallyillpatients:
                        sevendays.                                                              consensusandcontroversies”
                        Failuretoachieveenteralnutritionroute.                                  Edmundsetal.(26),“TheeffectsofdifferentIVfatemulsionsonclinicaloutcomes
                                                                                                incriticallyIllpatients”
                        Disabilitytoprovideadequatefoodandfluidsintheenteralmethod.              McClaveetal.(27),“Guidelinesfortheprovisionandassessmentofnutrition
                                                                                                supporttherapyintheadultcriticallyIllpatient:Societyof criticalcaremedicine
                                                                                                (SCCM)andAmericanSocietyforParenteralandEnteralNutrition(A.S.P.E.N)”
                        Pancreatitisassociatedwithjejunumintolerance.                           Hvasetal.(25),“Qualityandsafetyimpactontheprovisionofparenteral
                                                                                                nutritionthroughintroductionofanutritionsupportteam”
                        Traumarequiringfrequentgastrointestinalsurgicalprocedures.              Justoetal. (28),“Enteralorparenteralnutritionintraumaticbraininjury:A
                                                                                                prospectiverandomizedtrial”
                      ginwithinfivetosevendaysbeforesurgeryandcontinue                                 Table 2 shows the studies that carried out the benefits
                      inthepostoperativeperiod.Parenteralnutritionmayhave                        of enteralnutritioncomparedtoparenteral.
                      dangersforthepatientinperiodsoflessthanfivetoseven                               Inastudycomparingenteralandparenteralnutrition
                      days,thus,theyshouldstartforatreatmentperiodofmore                         patterns, by using an enteral method a definite reduction
                      thansevendays. Of course,itispossibletobeginthefeed-                       in infectious morbidity was demonstrated. The specified
                      ing of the parenteral before seven days if the energy re-                  reduction has also been reported in non-infectious com-
                      quirementsarenotavailableafteraweek(31).                                   plications and the duration of hospitalization in the ICU.
                           ICU patients with respiratory failure are not recom-                  Some of the studies did not report the difference in the
                      mendedforroutineusehigh-fatandlow-carbohydratefor-                         mortality of these two methods, and even showed a de-
                      mulations designed for respiratory problems and CO2 re-                    crease of mortality despite the increased infectious com-
                      ductions; however, they should be considered for patient                   plicationsbyparenteralmethod(33).
                      formulaswithlimitedfluidandhighcalorie(32).                                      In order to compare the complications of the two
                      4                                                                                                       CritCareNursJ.2018;11(3):e87976.