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Boise State University

ScholarWorks

Nursing Faculty Publications and Presentations

School of Nursing

6-1-2017

Risk Factors for Pressure Injuries Among Critical

Care Patients: A Systematic Review

Jenny Alderden

Boise State University

June Rondinelli

Kaiser Permanente Southern California Health Services

Ginette Pepper

University of Utah College of Nursing

Mollie Cummins

University of Utah College of Nursing

JoAnne Whitney

University of Washington

This document was originally published by Elsevier in International Journal of Nursing Studies. This work is provided under a Creative Commons Attribution-NonCommercial-NoDerivitaves 4.0 license. Details regarding the use of this work can be found at:http://creativecommons.org/licenses/ by-nc-nd/4.0/. doi:10.1016/j.ijnurstu.2017.03.012

Publication Information

Alderden, Jenny; Rondinelli, June; Pepper, Ginette; Cummins, Mollie and Whitney, JoAnne. (2017). "Risk Factors for Pressure

Injuries Among Critical Care Patients: A Systematic Review". International Journal of Nursing Studies, 71, 94-114.

http://dx.doi.org/

10.1016/j.ijnurstu.2017.03.012

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Review

Risk

factors

for

pressure

injuries

among

critical

care

patients:

A

systematic

review

Jenny

Alderden

a,d,e,

*

,

June

Rondinelli

b

,

Ginette

Pepper

a

,

Mollie

Cummins

a

,

JoAnne

Whitney

c

a

UniversityofUtahCollegeofNursing,102000E,SaltLakeCity,UT84112,UnitedStates b

KaiserPermanenteSouthernCaliforniaHealthServices,393EWalnutStreet7thFloor,Pasadena,CA91188,UnitedStates c

UniversityofWashington,Box357266,1959NEPacificSt.,Seattle,WA98195,UnitedStates dBoiseStateUniversity,1910WUniversityDrive,Boise,Idaho83725,UnitedStates e

St.Luke’sMeridianMedicalCenter,520SEagleRoad,Meridian,Idaho83642,UnitedStates

ARTICLE INFO

Articlehistory:

Received18October2016

Receivedinrevisedform24March2017 Accepted25March2017 Keywords: Criticalcare Pressureinjury Riskfactor Skin ABSTRACT

Objective:Toidentifyriskfactorsindependentlypredictiveofpressureinjury(alsoknownaspressure ulcer)developmentamongcritical-carepatients.

Design:Weundertookasystematicreviewofprimaryresearchbasedonstandardizedcriteriasetforthby theInstituteofMedicine.

Datasources:Wesearchedthefollowingdatabases:CINAHL(EBSCOhost),theCochraneLibrary(Wilson), Dissertations&ThesesGlobal(ProQuest),PubMed(NationalLibraryofMedicine),andScopus.Therewas nolanguagerestriction.

Method:Aresearchlibrariancoordinatedthesearchstrategy.Articlesthatpotentiallymetinclusion criteria were screened by two investigators. Among the articles that met selection criteria, one investigatorextracteddataandasecondinvestigatorreviewedthedataforaccuracy.Basedonaliterature search,wedevelopedatoolforassessingstudyqualityusingacombinationofcurrentlyavailabletools andexpertinput.WeusedthemethoddevelopedbyColemanetal.in2014togenerateevidencetables andasummarynarrativesynthesisbydomainandsubdomain.

Results:Of1753abstractsreviewed,158wereidentifiedaspotentiallyeligibleand18fulfilledeligibility criteria.Fivestudieswereclassifiedashighquality,twoweremoderatequality,ninewerelowquality, andtwowereofverylowquality.Age,mobility/activity,perfusion,andvasopressorinfusionemergedas importantrisk factorsforpressureinjurydevelopment,whereasresultsforriskcategoriesthatare theoreticallyimportant,includingnutrition,andskin/pressureinjurystatus,weremixed. Methodologi-callimitationsacrossstudieslimitedthegeneralizabilityoftheresults,andfutureresearchisneeded, particularlytoevaluateriskconferredbyalterednutritionandskin/pressureinjurystatus,andtofurther elucidatetheeffectsofperfusion-relatedvariables.

Conclusions:Resultsunderscoretheimportanceofavoidingoverinterpretationofasinglestudy,andthe importanceoftakingstudyqualityintoconsiderationwhenreviewingriskfactors.Maximalpressure injurypreventioneffortsareparticularlyimportantamongcritical-carepatientswhoareolder,have alteredmobility,experiencepoorperfusion,orwhoarereceivingavasopressorinfusion.

©2017TheAuthors.PublishedbyElsevierLtd.ThisisanopenaccessarticleundertheCCBY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Whatisalreadyknownaboutthistopic?

 Criticalcarepatientsareexposedtouniquepotentialriskfactors for pressure injury (PI) development, such as vasopressor infusionandtheeffectsofsevereillness.

 Although studies have examined PI risk among critical care patients,thereislittleconsensusaboutwhichfactorsinfluence PIriskinthecriticalcarepopulation.

* Correspondingauthorat:BoiseStateUniversity,1910WUniversityDrive,Boise, Idaho,83725,UnitedStates.

E-mailaddresses:Jenny.Alderden@utah.edu,jenny.alderden@gmail.com

(J.Alderden),June.L.Rondinelli@kp.org(J.Rondinelli),Ginny.Pepper@nurs.utah.edu

(G.Pepper),Mollie.Cummins@utah.edu(M.Cummins),joiewhit@uw.edu

(J.Whitney).

http://dx.doi.org/10.1016/j.ijnurstu.2017.03.012

0020-7489/©2017TheAuthors.PublishedbyElsevierLtd.ThisisanopenaccessarticleundertheCCBY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/4.0/).

InternationalJournalofNursingStudies71(2017)97–114

ContentslistsavailableatScienceDirect

International

Journal

of

Nursing

Studies

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Whatthispaperadds

Age,mobility/activity,poorperfusion,andvasopressorinfusion areriskfactorsforpressure-injurydevelopmentamongcritical carepatients.

Future research is needed to evaluate risk conferred by malnutrition,andskin/pressureinjurystatus.

Futureresearchisalsoneededtofurtherelucidateriskconferred byspecificperfusionrelatedvariables includinghighdosesof vasopressors, combinations of vasopressors, and duration of decreased oxygen delivery to tissues (hypotension and/or decreasedbloodoxygencontent).

1.Introduction

Hospital-acquiredpressure injuries (formerlycalledpressure ulcers)arelocalizedareasofdamagetotheskin,underlyingtissue, orboth,asaresultofpressure.Hospital-aquiredpressureinjuries occurin3%–34%ofhospitalizedpatientsworldwideandresultin longerhospitalstays,increasedmorbidity,andincreasedhuman suffering(Cremascoetal.,2013;Frankeletal.,2007;Gravesetal., 2005;SlowikowskiandFunk,2010).

Due tonegativeoutcomesassociated withpressure injuries, standards of practice include a recommendation to conduct pressureinjury riskassessmentandcomprehensiveskin assess-mentuponadmissionandatanytimethereisasignificantchange ina patient’scondition(NationalPressureUlcerAdvisoryPanel etal.,2014).Accurateriskassessmentalongwithcomprehensive skin assessment enables prompt recognition and treatment of pressureinjuries that occuramonghigh-risk patients, which is importantbecauseearly(Category1)pressureinjuriesarehighly treatable(Halfens etal., 2001);however,discernmentof which individualsareathighestriskforpressureinjuriesintheintensive careunit(ICU)isproblematicbecausetherisk-assessmentscales currentlyusedforcritical-carepatientstendtoidentifyalmostall patientsas“highrisk”(Kelleretal.,2002).

Critical-care patients represent a highly specialized patient population,andriskforpressureinjuriesinthispopulationislikely tobedifferentthan riskin otherpopulations, particularlyas it relates to perfusionand general skin status due toseverity of illness and treatments, includingvasopressor infusion,that are uniquetocritical-carepatients(Cox,2013).The purposeofthe current review is to identify factors that are independently associated with increased risk for pressure injuries among critical-care patients specifically. An independent risk factor retainsitsstatisticalassociationwiththeoutcomevariablewhen otherriskfactorsareincludedinthemodel;notethat indepen-dence is a statistical concept and does not imply causality (Colemanetal.,2013;Harrell,2001).

Weevaluatedidentifiedindependentriskfactorsinrelationto clinical relevance and in relation to recent pressure injury conceptualand theoreticalframeworks(NationalPressureUlcer AdvisoryPaneletal.,2014;Colemanetal.,2014).Wealsoevaluated riskfactorsinrelationtostudyquality,asarecentpressureinjury studyconductedinageneralpopulationdeterminedthatmostof theincludedstudieswereoflow orverylow quality(Coleman etal.,2013).

2.Methods

2.1.Researchprotocol

We undertooka systematicreview ofprimary research. Our approachwasbasedonthestandardizedcriteriasetforthbythe Institute of Medicine (Eden et al., 2011) for comparative

effectiveness reviews and modified to appraise risk-factor/ observationalstudies(Colemanetal.,2013).

2.2.Eligibilitycriteria

Weadaptedinclusioncriteriabasedonthemethodemployed byColemanetal.(2013),toinclude(a)primaryresearch;(b)adult sample; (c) ICU setting; (d) prospective cohort, retrospective record review, or controlled trial; and (e) identification of independentriskfactorsforpressureinjury(multivariateanalysis). Exclusioncriteriaincludedthefollowing:(a)limitedtopediatric patient population (age <18 years), (b) >25% of the study populationwereexcludedfromanalysisduetolosstofollowup or missing records, (c) prevalence or cross-sectional study, (d) limitedtoevaluationofa pressureinjuryrisk-assessment scale, and (e) limited tospinal cordinjury (SCI) patients(due tothe specialized physiology involved in spinal cordinjuries and the associated risk for pressure injury among individuals with SCI (Rappl,2008).Therewasnolanguagerestriction.

2.3.Searchstrategy

Wesearchedthemedicalsubjectheadingspressureinjuryand intensivecareunitsinadditiontofield-restrictedkeywordsforthe followingdatabases:CINAHL(EBSCOhost), theCochraneLibrary (Wilson),Dissertations&ThesesGlobal(ProQuest),andPubMed (NationalLibraryofMedicine).Wedownloadedourfinalresultson December 17, 2016. A complete description of the search is outlinedinAppendixA.

2.4.Dataextraction

Twoinvestigators(XX andXX) identifiedpotentiallyeligible studies. Among those deemed potentially eligible, XX noted whether each study met inclusion criteria for this review (or statedthereasonthestudydidnotmeetcriteria)andXXchecked XX’s categorizations. Disagreements were addressedby a third researcher,XX,andagreementwasdeterminedbyconsensus.In addition,oneinvestigator(XX)extracteddatapertainingtostudy design, population, setting, analysis, and results, and a second investigator(XX)reviewedthedataforaccuracy.

2.5.Qualityappraisal

Inanefforttoidentifyaquality-assessmenttoolforthecurrent review,weconductedaliteraturesearch.Wedeterminedthatno currently available checklists or scales fit closely with the objectives of the current review while offering adequate inter-raterreliability.

Weusedtheavailabletoolstoguidedevelopmentofourtoolfor assessingqualityamongpressureinjuryrisk-factorstudies.First, theauthorsofasystematicreviewofquality-assessmenttoolsfor observational studies concluded that available checklists and scalesdidnotdifferentiatewellbetweenpoorstudyreportingand a truly flawed study (Shamliyan et al., 2010). The authors recommendedthatinsteadofassigningasummativescorebased primarilyonreporting,qualityassessmentofobservational risk-factorstudiesshouldbeconductedbydefiningflawsindifferent domains—an approachthat results inmore transparent conclu-sionswhencomparedwithglobalscoringbasedonachecklistor summative evaluation tool. Similarly, authors of a systematic reviewofquality-appraisaltoolsforobservationalepidemiological studies recommended against summative scores and instead advised an approach based on evaluation of bias in particular qualitydomains(Sandersonetal.,2007).

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Thequality-appraisaltooldevelopedforthecurrentreview(see AppendixB)includesthedomainsidentifiedinSandersonetal. (2007)reviewofqualityappraisalamongobservationalstudies: methods for selecting participants, methods for measuring exposureandoutcomevariables,design-specificsourcesofbias, methods tocontrolconfounding, statistical methods(excluding control of confounding), and conflict of interest. Major and moderateflawsarenotedineach domaininwhichpresenceof amajorflawisasignificantindicatorthattheflawhassubstantially compromisedourconfidenceinthestudyconclusions.

Althoughthequality-appraisalmethodemployedinthisstudy

was focused on sources of bias in different domains, we

determined that an evaluative descriptor was necessary to facilitatestudyclassificationaccordingtothedegreeofactualor potential bias. Using the rubric provided in Appendix B, we employedthefollowingevaluationbased onspecificsourcesof bias:

1.High-qualitystudieshad0potentialsourcesofbiaswithmajor implicationsforstudyqualityand1potentialsourcesofbias withmoderateimplicationsforstudyquality;

2.Moderate-quality studies had 1 potential sourceof bias with majorimplicationsforstudyqualityand1potentialsourcesof biaswithmoderateimplicationsforstudyquality;or0potential sourcesofbiaswithmajorimplicationsforstudyqualityand2– 3potentialsourcesofbiaswithmoderateimplicationsforstudy quality;

3.Low-qualitystudieshad 1potentialsourceofbiaswithmajor implicationsforstudyqualityand2–4potentialsourcesofbias with moderate implications for study quality, or 0 potential sourcesofbiaswithmajorimplicationsforstudyqualityand4– 7potentialsourcesofbiaswithmoderateimplicationsforstudy quality;and

4.Very-low-qualitystudieshad2ormorepotentialsourcesofbias with major implications for study quality, or 8 potential sourcesofbiaswithmoderateimplicationsforstudyquality.

Indeterminatesourcesofbiaswereitemsthatmayormaynot haveintroducedbias;indeterminateitemswerenotedbutdidnot counttowardtheevaluativedescriptorcategory.Wesoughtexpert input during tool development, and the final tool reflects consensus among two experts in pressure injury research and oneexpertinobservationalresearch.

2.6.Datasynthesis

Meta-analysiswasnotfeasibleforthisreviewbecauseofahigh degreeofclinicalheterogeneityrelatedtopopulation, predictor

variableoperationalization,preventiveinterventions,anddifferent thresholdsforthepressureinjuryoutcomevariable(newCategory 1 and greater pressureinjury vs. newCategory 2 and greater) according tothe internationalNationalPressureUlcerAdvisory Panel/European Pressure Ulcer Advisory Panel (NPUAP/EPUAP) classificationsystem(NationalPressureUlcerAdvisoryPaneletal., 2014).Thepurposeofthereviewwastoidentifyriskfactorsrather thantoquantifytheeffectsizeoftherelationshipbetweenagiven factorandpressureinjurydevelopment;therefore,weconducteda narrativesynthesis. Weutilized thenarrativesynthesis method previouslyemployedbyColeman et al.(2013).We recordedall potential risk factors entered into multivariate analysis and identified the factors that emerged as independent factors for pressure injury risk. For studies using stepwise regression, we included factors that were not statistically significant upon bivariateanalysisifthosefactorswereidentifiedasindependent riskfactorsforpressureinjuriesinthefinalmodel(Colemanetal., 2013).Finally,wecategorizedrecordedriskfactorsandpotential riskfactorsintodomainsandsubdomains.

DomainswerestructuredaccordingtoColemanetal. (2014) interpretation of theNPUAP/EPUAP conceptual framework (see Fig.1).Domain1encompassesmechanicalboundaryconditionsto includesourcesofpressureandalsofrictionandshear,whichare conceptualizedasmechanicalboundaryconditionsratherthanas patientcharacteristics(Colemanetal.,2014).Domain2comprises thosefactorsthatinfluencethesusceptibilityandtoleranceofthe individual.Somefactorshaveaneffectonmechanicalboundary conditionsandonthe

susceptiblyandtoleranceoftheindividual,andthereforesome overlap exists between the two major domains; for example, diabetes affects mechanical load through sensory deficits and affects individual tolerance and susceptibility through altered perfusion.WedevelopedsubdomainsinrelationtoColemanetal. (2014) theoretical schema of a proposed causal pathway for pressure ulcer development (see Fig. 2), which built upon the NPAUP/EPUAP/Pan Pacific PressureInjury Alliance (PPPIA) con-ceptualframework(NationalPressureUlcerAdvisoryPaneletal., 2014)andidentifiedimmobility,skinandpressureinjurystatus, and poor perfusion as direct causal factors in pressure injury development(Colemanetal.,2014).

3.Results

3.1.Studycharacteristics

Of1753abstractsreviewed,158wereidentifiedaspotentially eligibleand18fulfilledeligibilitycriteria(seeFig.3).Theretained studies included 13 prospective cohort and five retrospective

Fig.1.EnhancementofNPUAP/EPUAP(2009)factorsthatinfluencesusceptibilityforpressureulcerdevelopment(Colemanetal.,2014,p.2229,usedwithpermission). J.Alderdenetal./InternationalJournalofNursingStudies71(2017)97–114 99

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recordreviews.Asummaryoftheincludedstudiesispresentedin Table1.

3.2.Qualityappraisal

Tworesearchersconductedthequalityappraisalandreached “substantial”agreementindependently,asevidencedbyKappa= 0.72 (Viera and Garrett, 2005). Afterinter-rater reliability was calculated,theresearchersreviewedanydiscrepanciesandcame

to agreement. When possible, we contacted study authors for clarificationpurposes.

QualityappraisalresultsareidentifiedinTable2.Theincluded studies had betweenzero and two major sources of bias, and betweenoneandsixmoderatesourcesofbias;overall,fivestudies wereclassifiedashighquality(SlowikowskiandFunk,2010;Cox and Roche, 2015;Suriadi etal., 2008;O’Brien et al.,2014; Cox, 2011),twowereofmoderatequality(Manzanoetal.,2010;Nijs etal.,2009),ninewereoflowquality(Frankeletal.,2007;Kaitani

Fig.2. Theoreticalschemaofproposedcausalpathwayforpressureulcerdevelopment.Thesolidarrowsshowthecausalrelationshipbetweenthekeyindirectcausalfactors andtheoutcome.Interruptedarrowsshowthecausalrelationshipbetweenotherpotentialindirectcausalfactorsandkeyindirectcausalfactorsandbetweendirectcausal factors.Interruptedarrowsalsodemonstrateinterrelationshipsbetweendirectcausalfactorsandindirectcausalfactors(Colemanetal.,2014,p.2229,usedwithpermission) (Colemanetal.,2014).

Fig.3.DecisionProcess.

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Table 1

Summary of Studies.

Study Authors Sample and Country Inclusion Criteria Design and Analysis

No. in Final Model (PI%), No. of PI and Category

Results: No. of Risk Factors (No. in Model), Model Risk-Factor Names: Odds Ration (95% Confidence Interval)

Study Quality

Compton et al. (2008)

713 general ICU patients in Germany 72-h stay

No pressure injury upon admission

Retrospective record review Logistic regression 698 (17%), 121 Categories 2–4 32 (6) Male gender: 1.8 (NR) Moist skin: 2.4 (NR) Edematous skin: 2.2 (NR) Centralized circulation: 2.4 (NR) Mottled skin: 2.0 (NR) Reddened skin: 2.3 (NR) MQS

Coleman et al. (2014) 347 medical–surgical ICU patients in the United States

24-h stay

No pressure injuey upon admission Age18 years Retrospective record review Logistic regression Model 1: 347 (18.7%), 65 >Category 1 Model 2: 327 (13.7%), 45 >Category 2 Model 1: 15 (4) Mobility: 0.439 (0.21–0.95) Age: 1.033 (1.003–1.064)

Length of ICU stay: 1.008 (1.005–1.011) Cardiovascular disease: 2.952 (1.3–6.4) Model 2: 15 (4)

Friction/shear: 5.715 (1.423–22.95) Length of ICU stay: 1.008 (1.004–1.012) Norepinephrine: 1.017 (1.001–1.033) Cardiovascular disease: 3.380 (1.223–9.347)

HQS

Cox and Roche (2015)

306 medical, surgical, and cardiothoracic ICU patients in the United States

24-h stay

No pressure injury upon admission Age18

Received a vasopressor during ICU stay

Retrospective record review Logistic regression 306 (13%), 41Category 1 11 (5) Cardiac arrest: 3.894 (0.998–15.118) Mechanical ventilation72 h: 23.604 (0.998-15.118) Hours of MAP less than 60 mm HG while on vasopressors: 1.096 (1.020–1.178)

Vasopressin: 4.816 (1.666–13.925)

Cardiac diagnosis at admission: 0.035 (0.002–0.764)

HQS

Cremasco et al. (2013)

160 modical–surgical ICU patients in three ICUs in Brazil

24-h stay

No pressure injury upon admission

Prospective cohort Logistic regression 160 (34.4%), 55, Category not reported NR (4) Male gender: 5.4 (1.42–22.09) Length of ICU stay: 1.120 (1.943–1.202) SAPSI score: 1.058 (1.004–1.114) NAS score: 0.916 (0.855–0.980)

LQS

Eachempati et al. (2001)

Phase 2: 412 surgical ICU patients in the United States

Length of stay>7 days Prospective cohort Logistic regression 55 (60%), 33Category 2 7 (5) Emergent admission: 36 (0.2290–0.7694) Age:–0.0131) Days in bed: 1.05 (-0.0013–0.0156) CURS day 8: 1.45 (-0.0048–-0.0833)

Days without any nutrition: 0.51 (-0.1095–-0.0334)

VLQS

Fife et al. (2001) 186 neurologic ICU patients in the United States

No pressure injury upon admission No diagnosis of brain death on life support pending organ donation

Prospective cohort Logistic regression 186 (12%), 23Category 2 NR (2) Braden score: NR (NR)

Low body mass index (BMI): NR (NR)

MQS

Frankel et al. (2007) 820 surgical ICU patients in the United States

Not reported Retrospective record review Logistic regression 820 (3%), 25Category 2 9 (4) Diabetes: 2.7 (1.1–6.4) Age: 2.9 (1.2–7.1) Creatinine: 3.7 (1.2–9.2) Spinal cord injury: 16.8 (1.5–182)

MQS

Kaitani et al. (2010) 98 ICU and high-care-unit patients in Japan

Age20 years

No pressure injury upon admisison 24-h stay Prospective cohort 98 (11.2%), 11 Categories 1–4 6 (2) Scheduled admission: 0.04 (0–0.47) Frequency of turning: 0.45 (0.21–0.97) LQS J. Alderden et al. / International Journal of Nursing Studies 71 (20 17 ) 97 – 11 4 10 1

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Table 1 (Continued)

Study Authors Sample and Country Inclusion Criteria Design and Analysis

No. in Final Model (PI%), No. of PI and Category

Results: No. of Risk Factors (No. in Model), Model Risk-Factor Names: Odds Ration (95% Confidence Interval)

Study Quality Unable to make major and frequent

position changes independently

Logistic regression

Manzano et al. (2010)

299 patients in nine ICUs in Spain Mechanical ventilation Age18 years Nonpregnant Prospective cohort Logistic regression 299 (15.7%), 47Category 2 16 (5)

Day 1 respiratory SOFA: 1.56 (1.026–2.360) Day 4 cardiovascular SOFA: 1.33 (1.066–1.664) Age: 1.042 (1.013–1.072)

Winter: 4.6 (1.99–10.59)

Length of mechanical ventilation: 1.042 (1.005–1.080)

HQS

Nijs et al. (2009) 520 surgical ICU patients in Belgium Age16 years 24-h expected stay Absence of burns Prospective cohort Logistic regression 463 (28.9%), 134 Categories 2–4 19 (9) Dopamine<5 mcg/kg/min: 6.1 (1.9–19.5) Vascular disease: 4.5 (2.0–10.2) Dialysis: 3.8 (1.0–13.9) “Adequate prevention”: 6.0 (1.9–18.6)

Frequency of turning six or more times daily or alternating mattress: 30.2 (12.2–74.8) “Turning”: 6.7 (2.7–16.4) Sedative use: 0.3 (0.1–0.7) Body temperature38.5: 0.2 (0.2–0.9) Sitting in chair: 0.1 (0.0–0.3) HQS

O’Brien et al. (2014) 2695 surgical and burn ICU patients in the United States

Age18 years 48-h ICU stay

Underwent a surgical procedure No pressure injury upon admission

Retrospective record review 2695 (10.7%), 288 Category 2 12 (7) Existing airway: 5.28 (3.63–7.67) Low BMI: 2.7 (1.45–5.04) Noncardiac surgery: 1.84 (1.31–2.59) History of heart failure: 1.78 (1.27–2.49) History of renal failure: 1.75 (1.27–2.39) ASA class 4 or 5: 1.63 (1.19–2.29) Age: 1.02 (1.01–1.03)

HQS

Sayar et al. (2009) 140 medical–surgical ICU patients in Turkey

At risk or at high risk on Waterlow pressure ulcer risk scale

Prospective cohort Logistic regression 140 (14.3%), 20Category 1 5 (2) Length of stay: 1.2 (1.1–1.3) Activity level: 0.3 (.02–0.7) MQS Slowikowski and Funk (2010)

369 surgical ICU petients in the United States

Age16 years Prospective cohort Logistic regression 369 (23.9%), 88, Category not reported 8 (3)

Braden Scale score: 1.3 (1.15–1.47) Diabetes: 1.93 (1.11–3.35) Age70 years: 2.14 (1.27–3.62)

HQS

Suriadi et al. (2008) 253 general ICU patients in Indonesia Age18 years Bedfast

No pressure injury upon admission 24-h stay and anticipated stay72 h

Prospective cohort Logistic regression 253 (28.4%), 72Category 1 NR (3) Interface pressure: 2.2 (1.6–2.9) Body temperature: 2.0 (1.7–2.5) Cigarette smoking: 1.6 (1.1–2.5) HQS

Tayyib et al. (2015) 84 general ICU patients in Saudi Arabia Age18 years Prospective cohort

84 (39.3%), 33 Categories 1–4

Model 1 Categories 1–4: 7 (3) Age: 1.254 (1.054–1.492) Longer ICU stay: 1.23 (1.014–3.309)

Infrequent repositioning: 250.04 (230–11,954.16) Model 2 Categories 2–4: 3 (2)

Longer ICU stay: 1.831 (1.054–1.492) Infrequent repositioning: 2.96 (1.23–7.153) MQS 10 2 J. Alderden et al. / International Journal of Nursing Studies 71 (20 17 ) 97 – 11 4

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Theaker et al. (2000) 286 general ICU patients in the United Kingdom

>24-h stay

No pressure injury upon admission Three or more pressure injury risk factors Prospective cohort Logistic regression 286 (26.9%), 77 Categories 2–4 18 (5) Norepinephrine infusion: 8.11 (3.64–18) APACHE II13: 2.4 (1.4–7.92) Fecal incontinence: 3.27 (1.32–8.3) Anemia: 2.81 (1.24–6.34)

Length of staythree days: 2.76 (1.06–7.05)

LQS

Ulker Efteli and Yapucu Gunes (2013)

70 general ICU patients in Turkey Age18 years

Expected ICU stay7 days No pressure injury upon admission Braden Scale score<12

Prospective cohort Logistic regression 70 (33%), 23Category 1 6 (2) Female gender: 0.15 (0.03–0.71)

Lower serum albumin level: 11.6 (1.92–70.4)

MQS

Yepes et al. (2009) 150 ICU patients in Bolivia Intubated

On mechanical ventilation Received vasopressor Prospective cohort Logistic regression 150 (26.7%), 40Category 2 3 (3) Presence of infection: 4.39 (6.92–18.25) Length of stay in the ICU: 1.13 (1.06–1.22) APACHE II: 1.06 (1.0–1.12)

LQS

NR = not reported. PI = pressure injury. ICU = intensive care unit. NR = not reported.

MQS = moderate-quality study. HQS = high-quality study. MAP = mean arterial pressure. LQS = low-quality study.

SAPSI = Simplified Acute Physiology Score. NAS = nursing activities score.

VLQS = very-low-quality study. CURS = Corneil ulcer risk score.

SOFA = sequential organ failure assessment. ASA = American Society of Anesthesiologists.

APACHE = acute physiology and chronic health evaluation.

J. Alderden et al. / International Journal of Nursing Studies 71 (20 17 ) 97 – 11 4 10 3

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Table2

StudyQuality:PotentialBias. Study MethodsforSelecting

Participants

StatisticalMethodsandControlof Confounding

MethodsforMeasuring Exposure Methodsfor Measuring OutcomeVariable Conflict of Interest Notesand Quality Appraisal Compton etal. (2008)

– Major:Inadequatenumberof eventsforanalysis

Moderate:Unclearstatistical reporting

– Moderate:Nurses

whowerenot speciallytrained identifiedpressure injuries – LQS Strength: Usedan independent cohortto validate model

Cox(2011) – Noteoneventsforanalysis:The authorincludedapoweranalysis indicatingtherewereenough events.

– Moderate:Nurses

whowerenot speciallytrained identifiedpressure injuries – HQS Coxand Roche (2015) – – – – – HQS Cremasco etal. (2013)

– Major:Inadequatenumberof eventsforanalysis

Moderate:Unclearstatistical reporting

Moderate:Non-independent factorsincludedintheanalysis withoutappropriateadjustment

– Major:Nocriteria fordesignationof woundasa pressureinjury Moderate:Nurses whowerenot speciallytrained identifiedpressure injuries Moderate:Limited descriptionofthe outcomevariable – VLQS Eachempati etal. (2001)

Moderate:Restrictedsampling (includedonlypatientswith LOS>6days)

Moderate:Unclearinclusion/ exclusioncriteria

Major:Clearlyincorrectstatistical methods

Moderate:Inappropriatestrategy formodelbuilding

– Major:Nocriteria fordesignationof woundasa pressureinjury Moderate:Nurses whowerenot speciallytrained identifiedpressure injuries Moderate:Limited descriptionofthe outcomevariable – VLQS Fifeetal. (2001)

– Major:Inadequatenumberof eventsforanalysis

Moderate:Unclearstatistical reporting – Moderate:Limited descriptionofthe outcomevariable – LQS Frankeletal. (2007) Indeterminate:Individuals appeartohavebeenexcluded fromthestudybutthe inclusion/exclu-sioncriteriaare notdefined

Major:Inadequatenumberof eventsforanalysis

– Moderate:Nurses

whowerenot speciallytrained identifiedpressure injuries – LQS Kaitanietal. (2010)

– Major:Inadequatenumberof eventsforanalysis

Moderate:>15%losttofollowupor missingrecords/inadequatedata collection

Moderate:Inappropriatestrategy formodelbuilding

Moderate:Variableoperationis unclear

– – LQS

Manzano etal. (2010)

– Major:Inadequatenumberof eventsforanalysis

Indeterminate:Noreportingof missingdataforpredictor variablesdespitehigh likelihoodofmissingdata

– – MQS

Nijsetal. (2009)

– Major:Inadequatenumberof eventsforanalysis

Moderate:Problematicstatistical methodswithmoderate implicationsforstudyfindings

Indeterminate:Potential temporalambiguity(itis possiblethatthepredictor variableoccurredafterthe pressureulcerevent)

– – MQS

O’Brienetal. (2014)

– – – Moderate:Nurses

whowerenot speciallytrained identifiedpressure injuries – HQS Sayaretal. (2009)

– Moderate:Sampledfrom “high-risk”patientsonarisk-assessment scaleandthenincludedattributes ofthesamescaleaspredictor variables

Moderate:Non-independent factorsareincludedinthe analysiswithoutproper adjustment

Moderate:Selectivereporting

– – LQS

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etal.,2010;Sayaretal.,2009;Tayyibetal.,2015;Theakeretal., 2000;UlkerEfteliandYapucuGunes,2013;Comptonetal.,2008; Fifeetal., 2001;Yepeset al.,2009), and twowereof verylow quality(Cremascoetal.,2013;Eachempatietal.,2001)(Table2). Themethodological limitationswe foundweresimilartoother reviewsofpressureinjuryrisk-factorstudiesinthesensethatmost oftheincludedstudies(61%)wereofeitherlowqualityorverylow quality(Kelleretal.,2002;Colemanetal.,2013).Eleven(64%)of the17includedstudiesdidnothaveadequatenumbersofpressure injuryeventsforanalysis, a limitationthatis reflectedin some studiesinthewideconfidenceintervalsassociatedwithreported oddsratios.

3.3.Pressureinjuryoutcomevariable

Twoof the 18 studies included for review didnot describe criteriausedtodesignateapressureinjury(Cremascoetal.,2013; Eachempati et al., 2001). Two studies did not report specific pressureinjurycategories(Cremascoetal.,2013;Slowikowskiand Funk, 2010), six studiesdesignated a pressure injury as a new injuryCategory1(CoxandRoche,2015;Kaitanietal.,2010;Sayar etal.,2009;Tayyibetal.,2015;Theakeretal.,2000;UlkerEfteliand YapucuGunes,2013), eight studiesincludedonlynewpressure injuriesthatwereCategory2(Frankeletal.,2007;O’Brienetal., 2014;Manzanoetal.,2010;Nijsetal.,2009;Comptonetal.,2008; Fifeetal.,2001;Yepesetal.,2009;Eachempatietal.,2001),and two studies included separate models for pressure injuries Category1andCategory2(Table1)(Cox,2011;Tayyibetal., 2015).

3.4.Risk-Factordomainsandsubdomains

Theauthorsof14studiesreportedalloftheriskfactorsentered into multivariate modeling as well as those that emerged as

independentlypredictiveofpressureinjury(Frankeletal.,2007; SlowikowskiandFunk,2010;CoxandRoche,2015;O’Brienetal., 2014;Cox,2011; Manzanoetal.,2010;Nijsetal.,2009;Kaitani etal.,2010;Sayaretal.,2009;Tayyibetal.,2015;Theakeretal., 2000;UlkerEfteliandYapucuGunes,2013;Comptonetal.,2008; Eachempatietal.,2001),whereasauthorsofthreestudiesreported onlythevariablesthatemergedassignificantfrommultivariate modeling(Cremascoet al.,2013;Suriadi etal.,2008;Fifeetal., 2001).A summary of risk factorsentered intothe multivariate model(whenavailable)and thosethatemergedasindependent riskfactorsaresummarizedbystudy(Table1)andbyrisk-factor domain(seeTable3)(Colemanetal.,2013).

3.4.1.Domain1:mechanicalboundaryconditions

Mechanicalboundaryconditionsareaspectsthatinfluencethe magnitudeofthemechanicalload,thetimeduration,andalsothe typeofloading(pressure,friction,shear;Fig.1)(NationalPressure UlcerAdvisoryPaneletal.,2014).Weextendedthiscategoryto includebodysizebecauseofthepotentialforincreased mechani-calloadduetobonyprominenceamongunderweightindividuals.

We also included emergent admission because emergency

department gurneys have a suboptimal surface (Denby and Rowlands, 2010), and surgical time as time in surgery confers immobility.

3.4.1.1.Body size. Onemoderate-quality study(Manzanoet al., 2010)andonelow-qualitystudy(Comptonetal.,2008)included body size in the multivariate analysis, but neither weight nor heightemergedassignificantuponmultivariateanalysis(Table3). Nostudyincludedchangeinweight,however,whichmighthave been useful for assessing fluid shifts. Additionally, no study included a height/weight composite such as body mass index, which would have indicated underweightor excessive adipose tissue.

Table2(Continued)

Study MethodsforSelecting Participants

StatisticalMethodsandControlof Confounding

MethodsforMeasuring Exposure Methodsfor Measuring OutcomeVariable Conflict of Interest Notesand Quality Appraisal ofresults

Moderate:Unclearstatistical reporting Slowikowski andFunk, 2010) – – – Moderate:Limited descriptionofthe outcomevariable – HQS Suriadietal. (2008)

– – Moderate:Unclearstatistical

reporting

– – HQS

Tayyibetal. (2015)

– Major:Inadequatenumberof eventsforanalysis

Moderate:Nonindepen-dent factorsincludedintheanalysis withoutappropriateadjustment

– Moderate:Nurses

whowerenot speciallytrained identifiedpressure injuries – LQS Theakeretal. (2000)

– Major:Inadequatenumberof eventsforanalysis

Moderate:>15%losttofollowupor missingrecords

Moderate:Nonindepen-dent factorsincludedintheanalysis withoutappropriateadjustment

– Moderate:Nurses

whowerenot speciallytrained identifiedpressure injuries Moderate:Limited descriptionofthe outcomevariable – LQS UlkerEfteli and Yapucu Gunes (2013)

Moderate:Restrictedsampling (includedonlypatientswith LOS>6days)

Major:Inadequatenumberof eventsforanalysis

– Moderate:Nurses

whowerenot speciallytrained identifiedpressure injuries – LQS Yepesetal. (2009)

Moderate:Restrictedsampling (includedonlypatientson mechanicalventilationand vasopressorsupport)

Moderate:Nonindepen-dent factorsincludedintheanalysis withoutappropriateadjustment Moderate:Unclearstatistical reporting

– Moderate:Nurses

whowerenot speciallytrained identifiedpressure injuries

– LQS

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Table3

SummaryofEvidenceforRiskFactorDomainsandSubdomains.

Variable StudiesWithVariableSignificant inMultivariateModel

StudyQuality(StudyAuthors)Variable: OddsRatio(95%ConfidenceInterval)

StudiesWithVariableNotSignificant inMultivariateModel

StudyQuality(StudyAuthors)Variable

Domain1:MechanicalBoundaryConditions

Bodysize – MQS(Manzanoetal.,2010)Bodyweight

LQS(Comptonetal.,2008)Bodyweight andheight

Frictionandshear HQS(Cox,2011)Friction/shear:5.715(1.423–22.95) – Emergentvs.scheduledadmission LQS(Kaitanietal.,2010)Scheduledadmission:0.04(0–

0.47)

VLQS(Eachempatietal.,2001)Emergentadmission:36 (0.2290–0.7694)

HQS(O’Brienetal.,2014)Emergent admission

MQS(Manzanoetal.,2010)Typeof admission(medicalvs.surgical) LQS(Tayyibetal.,2015)Emergent admission

LQS(Kaitanietal.,2010)Admissiontype

Domain1Subdomain:Immobility

Mental/neurologicstatus – MQS(Nijsetal.,2009)GCS:openseyes MQS(Nijsetal.,2009)GCS:movement, localizespain

MQS(Nijsetal.,2009)GCS:movement, followscommands

LQS(Comptonetal.,2008)MinimumGCS LQS(Comptonetal.,2008)MaximumGCS LQS(Sayaretal.,2009)Consciousness LQS(Sayaretal.,2009)Cooperation LQS(Theakeretal.,2000)Pain Mobility/activity HQS(Cox,2011)Mobility:0.439(0.21–0.95)

LQS(Sayaretal.,2009)Activitylevel:0.3(0.2–0.7) –

Sensoryperception – HQS(Cox,2011)Sensoryperception

Surgicalfactors HQS(O’Brienetal.,2014)Noncardiacsurgery:1.84(1.31– 2.59)

LQS(Tayyibetal.,2015)Operationtime

Turning/repositioningandsurface HQS(Suriadietal.,2008)Interfacepressure:2.2(1.6–2.9) MQS(Nijsetal.,2009)“Adequateprevention”:6.0(1.9– 18.6)

MQS(Nijsetal.,2009)Frequencyofturningsixormore timesdailyoralternatingmattress:30.2(12.2–74.8) MQS(Nijsetal.,2009)“Turning”:6.7(2.7–16.4) MQS(Nijsetal.,2009)Sittinginchair:0.1(0.0–0.3) LQS(Tayyibetal.,2015)Infrequentrepositioning:2.96 (1.23–7.153)

LQS(Kaitanietal.,2010)Frequencyofturning:0.45 (0.21–.0.97)

HQS(SlowikowskiandFunk,2010)Not repositioned

LQS(Theakeretal.,2000)Toounstableto turn

Domain2:SusceptibilityandToleranceoftheIndividual

Age HQS(Cox,2011)Age:1.033(1.003–1.064) HQS(O’Brienetal.,2014)Age:1.02(1.01–1.03) HQS(SlowikowskiandFunk,2010)Age70years:2.14 (1.27–3.62)

MQS(Frankeletal.,2007)Age:2.9(1.2–7.1) LQS(Tayyibetal.,2015)Age:1.254(1.054–1.492) VLQS(Eachempatietal.,2001)Age:1.08(0.0026–0.0131)

MQS(Manzanoetal.,2010)Age

Bodytemperature HQS(Suriadietal.,2008)Bodytemperature:2.0(1.7–2.5) MQS(Nijsetal.,2009)Bodytemperature38.5:0.2 (0.2–0.9)

LQS(Comptonetal.,2008)Maximum bodytemperature

Diagnosis(exceptingdiagnosisrelatedtooxygenationand perfusion,includedbelowunderSubdomain:PoorPerfusion)

HQS(O’Brienetal.,2014)Historyofrenalfailure:1.75 (1.27–2.39)

LQS(Frankeletal.,2007)Spinalcordinjury:16.8(1.5– 182)

LQS(Yepesetal.,2009)Presenceofinfection:4.39(6.92– 18.25)

HQS(O’Brienetal.,2014)Historyofliver disease

MQS(Manzanoetal.,2010)Multipleorgan failure

MQS(Nijsetal.,2009)Gastrointestinal diagnosis

LQS(Tayyibetal.,2015)Historyofkidney disease

Laboratoryvalues(exceptingvaluesrelatedtooxygenationand perfusion,includedbelowunderSubdomain:PoorPerfusion)

LQS(Frankeletal.,2007)Creatinine:3.7(1.2–9.2) LQS(Theakeretal.,2000)Anemia:2.81(1.24–6.34)

HQS(CoxandRoche,2015)Severeanemia LQS(Theakeretal.,2000)Maximum serumpotassium

LQS(Comptonetal.,2008)Maximum creatinine

LQS(Comptonetal.,2008)Maximum bloodglucose

LQS(Comptonetal.,2008)Maximum c-reactiveprotein

LQS(Comptonetal.,2008)Minimum thromboplastintime

LQS(Comptonetal.,2008)Maximum serumbilirubin

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Table3(Continued)

Variable StudiesWithVariableSignificant inMultivariateModel

StudyQuality(StudyAuthors)Variable: OddsRatio(95%ConfidenceInterval)

StudiesWithVariableNotSignificant inMultivariateModel

StudyQuality(StudyAuthors)Variable

LQS(UlkerEfteliandYapucuGunes,2013) Hemoglobin

LQS(UlkerEfteliandYapucuGunes,2013) Bloodglucose

LQS(Sayaretal.,2009)C-reactiveprotein LQS(Theakeretal.,2000)Coagulopathy Lengthofstay HQS(Cox,2011)LengthofICUstay:1.008(1.005–1.011)

LQS(Sayaretal.,2009)Lengthofstay:1.2(1.1–1.3) LQS(Tayyibetal.,2015)LongerICUstay:1.831(1.014– 3.309)

LQS(Yepesetal.,2009)Lengthofstay:1.13(1.06–1.22) LQS(Theakeretal.,2000)Lengthofstay>3days:2.76 (1.08–7.05)

VLQS(Cremascoetal.,2013)LengthofICUstay:1.120 (1.943–1.202)

VLQS(Eachempatietal.,2001)Daysinbed:1.05 (-0.0013–0.0156)

HQS(CoxandRoche,2015)Hospital lengthofstay

HQS(CoxandRoche,2015)Lengthofstay beforeICUadmission

HQS(CoxandRoche,2015)ICUlengthof stay

MQS(Manzanoetal.,2010)ICUlengthof stay

MQS(Manzanoetal.,2010)Pre-ICU hospitalstay

LQS(Comptonetal.,2008)DurationofICU stay

Medication(exceptingvasopressors)andtreatments MQS(Nijsetal.,2009)Sedativeuse:0.3(0.1–0.7) MQS(Nijsetal.,2009)Dialysis:3.8(1.0–3.9)

HQS(O’Brienetal.,2014)Current corticosteroiduse

HQS(SlowikowskiandFunk,2010) Orthotics

HQS(SlowikowskiandFunk,2010) Hemodialysis

MQS(Nijsetal.,2009)Physicalfixation MQS(Nijsetal.,2009)Majoranalgesics MQS(Nijsetal.,2009)“Floatingheels” LQS(Comptonetal.,2008)Sedation LQS(Comptonetal.,2008)Insulintherapy LQS(Theakeretal.,2000)Current corticosteroiduse

Nutritionandlaboratoryvaluesrelatedtonutritionstatus LQS(UlkerEfteliandYapucuGunes,2013)Lowerserum albuminlevel:11.6(1.92–70.4)

VLQS(Eachempatietal.,2001)Dayswithoutany nutrition0.51(-0.1095–-0.0334)

HQS(Cox,2011)Nutrition

LQS(Comptonetal.,2008)Parenteral nutrition

LQS(Kaitanietal.,2010)Nutrition LQS(Theakeretal.,2000)Serumalbumin LQS(Theakeretal.,2000)Reduced nutritionalintake

Severityofillness/healthstatus HQS(CoxandRoche,2015)Cardiacarrest:3.894(0.998– 15.118)

HQS(O’Brienetal.,2014)ASAclass4or5:1.63(1.19– 2.23)

MQS(Manzanoetal.,2010)Day1respiratorySOFA:1.56 (1.026–2.360)

MQS(Manzanoetal.,2010)Day4cardiovascularSOFA: 1.33(1.066–1.664)

LQS(Yepesetal.,2009)APACHEII:1.06(1.0–1.12) LQS(Theakeretal.,2000)APACHEII>13:2.4(1.4–7.92) VLQS(Cremascoetal.,2013)SAPSIIscore:1.058(1.004– 1.114)

HQS(Cox,2011)APACHE

HQS(CoxandRoche,2015)APACHEII HQS(CoxandRoche,2015)DiedinICU MQS(Manzanoetal.,2010)Hospital mortality

MQS(Nijsetal.,2009)APACHEII LQS(UlkerEfteliandYapucuGunes,2013) APACHEII

LQS(Comptonetal.,2008)ICUmortality LQS(Comptonetal.,2008)TISS LQS(Kaitanietal.,2010)APACHEII LQS(Theakeretal.,2000)Peripheral vasculardisease

VLQS(Eachempatietal.,2001)MODS VLQS(Eachempatietal.,2001)APACHEIII

Domain2Subdomain:PoorPerfusion

IncludingFactorsThatAffectOxygenationandPerfusionStatus/DeliveryofOxygentotheTissues

Bloodpressure HQS(CoxandRoche,2015)HoursofMAPlessthan 60mmHGwhileonvasopressors:1.096(1.020–1.178)

HQS(Cox,2011)Meanarterialpressure HQS(Cox,2011)Systolicbloodpressure HQS(Cox,2011)Diastolicbloodpressure Diagnosisrelatedtooxygenationand/orperfusion(alsoincluded

inglobaldiagnosis,above)

HQS(Cox,2011)Cardiovasculardisease:2.952(1.3–6.4) HQS((CoxandRoche,2015)Cardiacdiagnosisat admission:0.035(0.002–0.764)

HQS(O’Brienetal.,2014)Historyofheartfailure:1.78 (1.27–2.49)

HQS(SlowikowskiandFunk,2010)Diabetes:1.93(1.11– 3.35)

HQS(Suriadietal.,2008)Cigarettesmoking:1.6(1.1–2.5) MQS(Nijsetal.,2009)Vasculardisease:4.5(2.0–10.2) LQS(Frankeletal.,2007)Diabetes:2.7(1.1–6.4)

HQS(O’Brienetal.,2014)Historyof diabetes

MQS(Manzanoetal.,2010)Septicshock MQS(Manzanoetal.,2010)Acute respiratorydistresssyndrome

LQS(Frankeletal.,2007)Vasculardisease LQS(Comptonetal.,2008)Sepsis LQS(Tayyibetal.,2015)Historyof cardiovasculardisease

LQS(Theakeretal.,2000)Diabetes LQS(Theakeretal.,2000)Historyof smoking

Heartrateandmonitoring LQS(Comptonetal.,2008)Maximum heartrate

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Table3(Continued)

Variable StudiesWithVariableSignificant inMultivariateModel

StudyQuality(StudyAuthors)Variable: OddsRatio(95%ConfidenceInterval)

StudiesWithVariableNotSignificant inMultivariateModel

StudyQuality(StudyAuthors)Variable

LQS(Comptonetal.,2008)Invasive monitoring

Oxygenation/ventilation HQS(CoxandRoche,2015)mechanicalventilation longerthan72h:23.604(6.427-86.668)

HQS(O’Brienetal.,2014)existingairway:5.28 (3.63-7.67)

MQS(Manzanoetal.,2010)lengthofmechanical ventilation:1.042(1.005-1.080)

HQS(SlowikowskiandFunk,2010) Ventilatorsupport

MQS(Manzanoetal.,2010)Pa02/Fi02 ratioonDay1

MQS(Nijsetal.,2009)Mechanical ventilation

LQS(Comptonetal.,2008)Minimum PaCO2

LQS(Comptonetal.,2008)Minimum arterialpH

LQS(Comptonetal.,2008)Mechanical ventilation

LQS(Comptonetal.,2008)Cyanosis LQS(Tayyibetal.,2015)Mechanical ventilation

Vasopressor HQS(Cox,2011)Norepinephrine:1.017(1.001–1.033) HQS(CoxandRoche,2015)Vasopressininfusion:4.816 (1.666–13.925)

MQS(Nijsetal.,2009)Dopamine<5mcg/kg/min:6.1 (1.9–19.5)

LQS(Theakeretal.,2000)Norepinephrineinfusion:8.11 (3.64–18)

LQS(Comptonetal.,2008)Vasopressor therapy

LQS(Frankeletal.,2007)Vasopressor therapy

LQS(Theakeretal.,2000)Dopamine LQS(Theakeretal.,2000)Epinephrine LQS(Theakeretal.,2000)Norepinephrine

Domain2Subdomain:Skin/PressureInjuryStatus IncludingFactorsThatAffectSkinandPressureInjuryStatus

Moisture LQS(Comptonetal.,2008)Moistskin:2.4(NR) LQS(Theakeretal.,2000)Moisture Skin/externalskinfactors/PIstatus LQS(Comptonetal.,2008)Edematousskin:2.2(NR)

LQS(Comptonetal.,2008)Centralizedcirculation:2.4 (NR)

LQS(Comptonetal.,2008)Mottledskin:2.0(NR) LQS(Comptonetal.,2008)Reddenedskin:2.3,(NR) LQS(Theakeretal.,2000)Fecalincontinence:3.27(1.32– 8.3)

HQS(CoxandRoche,2015)Peripheral necrosisinpatientsreceivingvasopressors HQS(SlowikowskiandFunk,2010)Edema MQS(Nijsetal.,2009)Pittingedema LQS(Comptonetal.,2008)Lividskin LQS(Comptonetal.,2008)Hyperemic skin

LQS(Kaitanietal.,2010)Edema LQS(Theakeretal.,2000)Edema

OtherFactorsNotIncludedInDomains1or2

Gender LQS(UlkerEfteliandYapucuGunes,2013)Female gender:0.15(0.03–0.71)

LQS(Comptonetal.,2008)Malegender:1.8(NR) VLQS(Cremascoetal.,2013)Malegender:5.6(1.42– 22.09)

LQS(Kaitanietal.,2010)genderG

Risk-assessmentscales HQS(SlowikowskiandFunk,2010)BradenScalescore: 1.3(1.15–1.47)

LQS(Fifeetal.,2001)BradenScalescore:NR(NR) VLQS(Eachempatietal.,2001)CURSDay8:1.45 (-0.0048–-0.0833)

HQS(Cox,2011)BradenScaletotal HQS(CoxandRoche,2015)BradenScaleat hospitaladmission

HQS(CoxandRoche,2015)BradenScaleat ICUadmission

LQS(Comptonetal.,2008)Waterlowscore LQS(Tayyibetal.,2015)BradenScalescore Otherfactors MQS(Manzanoetal.,2010)Winteradmission:4.6(1.99–

10.59)

VLQS(Cremascoetal.,2013)NASscore:0.916(0.855– 0.980)

AdaptedfromColemanetal.(2013). HQS=high-qualitystudy.

MQS=moderate-qualitystudy. LQS=low-qualitystudy. VLQS=very-low-qualitystudy. GCS=GlaslowComaScore.

APACHE=AcutePhysiologyandChronicHealthEvaluation. TISS=TraumaInjurySeverityScore.

MODS=multipleorgandysfunctionsyndrome.

PA02/FI02=ratioofarterialoxygenpartialpressuretofractionalinspiredoxygen. PaCO2=carbondioxidepartialpressure.

MAP=meanarterialpressure. CURS=Corneilulcerriskscore. NAS=nursingactivitiesscore. PI=pressureinjury.

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3.4.1.2.Frictionandshear. Recentdevelopmentsinpressureinjury researchindicatethatfriction-inducedskininjuriesarenottrue pressure injuries, whereas shearing forces cause a decrease in regionalbloodflowandthereforeareimportantinpressureinjury risk(BrienzaandAntokal,2015;Manoramaetal.,2013).Authorsof onlyonestudy(Cox,2011)enteredashear-relatedvariableinto multivariatemodeling;thestudy,whichwasofhighquality,found thatfriction/shear(asdefinedbytheBradenScale)(Bradenand Bergstrom,1987)wasindependentlypredictiveofpressureinjury development(Table3).

3.4.1.3. Emergent versus scheduled admission. We included

emergent admission in Domain 1 because time in the

emergency department is associated with time spent on

suboptimal surfaces such as gurneys. (Denby and Rowlands, 2010) Five study authors entered admission type into their statistical model. (O’Brien et al., 2014; Manzano et al., 2010; Kaitanietal.,2010;Tayyibetal.,2015;Eachempatietal.,2001)In twoofthosestudies(33%),(Kaitanietal.,2010;Eachempatietal.,

2001) emergent admission was found to be independently

predictive for pressure injury development; however, the two studieswereoflow-andvery-lowquality.

3.4.2.Domain1subdomain:immobility

Within Domain 1, Coleman et al. (2014) schema depicts

immobilityas a direct causal factor (Fig. 2). Therefore, factors associatedwiththissubdomainarepresentedbelow.

3.4.2.1.Mental/Neurologicstatus. Researchersinfourstudies,(Nijs etal.,2009;Sayaretal.,2009;Theakeretal.,2000;Comptonetal., 2008)includingonemoderate-qualitystudy(Nijsetal.,2009)and threelow-qualitystudies(Sayaretal.,2009;Theakeretal.,2000; Compton et al., 2008), entered variables related to neurologic statusintomultivariate analysis.Novariables relatedtomental statusemergedinmultivariateanalysis(Table3).

3.4.2.2.Mobility/Activity. Onehigh-qualitystudy(Cox,2011)and onelow-qualitystudy(Sayaretal.,2009)eachidentifiedmobility and activity level, respectively, as independently predictive of pressureinjuries(Table3).

3.4.2.3.Sensoryperception. Sensoryperceptionwasenteredinto thestatisticalmodelofonehigh-qualitystudybutdidnotemerge asanindependentriskfactor(Cox,2011).

3.4.2.4.Surgicalfactors. Informationpertainingtosurgicalfactors was limited. One high-quality study19 found that undergoing noncardiacsurgerywas anindependentriskfactor forpressure injury,whereasonelow-qualitystudy(Tayyibetal.,2015)entered operativetimeintothemultivariatemodel,butitdidnotemergeas anindependentriskfactor(Table3).

3.4.2.5.Turning/Repositioningandsurface. Overall,authorsofsix studiesenteredoneormoreturning-and/orrepositioning-related variablesintothestatisticalmodel(SlowikowskiandFunk,2010; Suriadietal.,2008; Nijsetal.,2009;Kaitanietal.,2010;Tayyib etal.,2015;Theakeretal.,2000);onestudyenteredfourvariables relatedtopositioning(Nijsetal., 2009)(Table3).Resultswere conflicting.Intheirmoderate-qualitystudy,Nijsetal.(2009)found that more frequent turning was an independent risk factor for pressure injury development, whereas two low-quality studies (Kaitani et al., 2010; Tayyib et al., 2015), each found that less frequentrepositioningwas independentlypredictive ofpressure injuryrisk(Table3).Nijsetal.speculatedthatperhapshigh-risk patientsexperiencedenhanced nursingvigilanceinturningand repositioning(Nijsetal.,2009).

3.4.3.Domain2:susceptibilityandtoleranceoftheindividual Domain2includesfactorsthatinfluencethesusceptibilityand toleranceoftheindividual(Fig.1).SubdomainswithinDomain2 are skin/pressure injury status, which includes existing and previous pressure injuries and general skin status, and poor perfusion, which encompasses conditions that alter oxygen deliverytothetissues(Colemanetal.,2014).

3.4.3.1.Bodytemperature. Threestudies,(Suriadietal.,2008;Nijs etal.,2009;Comptonetal.,2008)includingoneofhighquality,one of moderate quality, and one of low quality, included body temperatureinmultivariateanalysis,withconflictingresults.The high-qualitystudyfoundthatfeverwasanindependentriskfactor for pressure injury development (Suriadi et al., 2008); the moderate-qualitystudyfoundthatfeverwas aprotectivefactor (Nijsetal.,2009),andinthelow-qualitystudy(Comptonetal., 2008),feverdidnotemergeassignificantinmultivariateanalysis (Table2).

3.4.3.2. Diagnosis not directly related to oxygenation and

perfusion. Renal failure and high creatinine were each

determined to be independent risk factors for pressure injury developmentinonehigh-qualitystudy(O’Brienetal.,2014)and one low-quality study (Frankel et al., 2007), respectively. Researchers in one high-quality (Slowikowski and Funk, 2010) andonemoderate-qualitystudy(Nijsetal.,2009)entereddialysis intomultivariatemodeling.Inthemoderate-qualitystudy,dialysis was independently predictive of pressure injury development, whereasdialysisdidnotemergeasanindependentriskfactorin the high-quality study. Serum creatinine was independently predictive of pressure injury development in one low-quality study(Frankeletal.,2007)(Table3).

3.4.3.3. Laboratory values. Researchers in six studies (Frankel etal.,2007;CoxandRoche,2015;Sayaretal.,2009;Theakeretal., 2000;UlkerEfteliandYapucuGunes,2013;Comptonetal.,2008), includingonehigh-qualitystudy, enteredlaboratoryvaluesinto multivariate analysis (apart from albumin, which is discussed under“Nutrition,”andblood-gasvalues,whichareincludedinthe oxygenationresults;seeTable2).Onlytwolaboratoryvalueswere statisticallysignificantuponmultivariateanalysis:creatininewas anindependentriskfactorinonelow-qualitystudy(Frankeletal., 2007), and anemia emerged inone low-quality study(Theaker etal.,2000).

3.4.3.4. Length of stay. Length of stay (LOS) independently

predicted risk for pressure injury development in seven

(Cremasco et al., 2013; Cox, 2011; Sayar et al., 2009; Tayyib etal.,2015;Theakeretal.,2000;Yepesetal.,2009;Eachempati et al.,2001)ofthe11studiesthat includedLOSin multivariate analysis(Table2)(Cremascoetal.,2013;CoxandRoche,2015;Cox, 2011;Manzanoetal.,2010;Sayaretal.,2009;Tayyibetal.,2015; Theaker et al., 2000;Comptonet al., 2008; Yepes et al.,2009; Eachempatietal.,2001;Blyetal.,2016).Onlyonestudy(Manzano etal.,2010).however,differentiatedLOSpriortopressureinjury development, which is important, because development of a pressure injury increases thelength of a hospital stay (Allman etal.,1999).

3.4.3.5. Medications. Among five studies that included

medications other than vasopressors (Slowikowski and Funk, 2010;O’Brienetal.,2014;Nijsetal.,2009;Theakeretal.,2000; Compton et al., 2008), one moderate-qualitystudy (Nijs et al., 2009)foundthatsedativeusewasanindependentriskfactorfor pressureinjurydevelopment(Table3).

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3.4.3.6. Nutrition. In the current review, only one low-quality study determined that a nutrition-related variable (serum albumin) was independently predictive of pressure injury risk (UlkerEfteliandYapucuGunes,2013).Fourotherstudiesevaluated nutrition-relatedvariables(Cox,2011;Kaitanietal.,2010;Theaker etal.,2000;Comptonetal.,2008),butnutritiondidnotemergeas predictiveinmultivariatemodeling(Table3).Ofnote,one very-low-qualitybutfrequentlycitedstudyindicatedthatdayswithout nutrition was an independent risk factor for pressure injury development(Eachempatietal.,2001);inthatstudy,however,the datapresentedintablesandtheassociatedoddsratioindicatethe opposite:thatdayswithoutnutritionwasaprotectivefactor.That paradoxicalfindingwasactuallyreplicatedinthebivariateanalysis conducted by Slowikowski and Funk (Slowikowski and Funk, 2010),buttheauthorsdidnotenternutritioninthemultivariate analysis because they thought it might have been a spurious finding.

3.4.3.7.SeverityofIllness/Healthstatus. Eightstudiesincludedthe AcutePhysiologyandChronicHealthEvaluation(APACHE)scoreas amarkerofseverityofillnessintheirmultivariatemodel(Coxand Roche, 2015; Cox, 2011; Nijs et al., 2009; Kaitaniet al., 2010; Theakeretal.,2000;UlkerEfteliandYapucuGunes,2013;Yepes etal.,2009;Eachempatietal.,2001),andtwolow-qualitystudies (Theakeretal.,2000;Yepesetal.,2009),identifiedtheAPACHE scoreaspredictiveofpressureinjuryrisk(Table2).TheAPACHE scoreis calculated usingmeasurements that occur within24h after admission, and the score is not repeated; therefore, the APACHE may not be a sensitive indicator of severity of illness throughouta several-day hospitalcourse (Breslowand Badawi, 2012).Furthermore,expertscontendthattheAPACHEshouldbe usedprimarilytoprovideperformancecomparisonsbetweenICUs ratherthan toprovideanassessment ofan individualpatient’s illnessseverity(BreslowandBadawi,2012).

Amongothermarkersofillnessseverity,anAmericanSocietyof Anesthesiologists(ASA)Class-4orClass-5scorewasan indepen-dentrisk factor for pressureinjuries in one high-quality study, (O’Brienetal.,2014)andsequentialorganfailureassessmentson Days 1 and 4 were also independent risk factors for pressure injuries in a moderate-quality study (Manzano et al., 2010) (Table3).Hospitaland/orICUmortalitywereconsideredinone high-quality study (Cox and Roche, 2015) and two moderate-qualitystudies(Manzanoetal.,2010;Comptonetal.,2008),but mortality did not emerge as statistically significant in the multivariatemodel.

3.4.4.Domain2subdomain:poorperfusion

The subdomain of poorperfusionincludes factorsthat alter oxygendeliverytotissues.PoorperfusionisincludedinColeman etal.conceptualschemaasadirectcausalfactorinpressureinjury development(Colemanetal.,2014).

3.4.4.1.Bloodpressure. Two high-qualitystudiesincludedblood pressure(CoxandRoche,2015;Cox,2011),andbloodpressurewas anindependentriskfactorinoneofthestudies(CoxandRoche, 2015).Coxdefinedbloodpressureasthetotalnumberofhoursin thefirst48hthatthepatienthadameanarterialpressure<60mm Hg,and/orsystolicbloodpressure <90mmHg,and/ordiastolic blood pressure <60mm Hg; however, in that study, the mean lengthofstaywasfivedays,andthereforebloodpressurereadings werenotrecordedformorethanhalfofatypicalpatient’sICUstay (Cox,2011).Inananotherstudy,CoxandRochedeterminedthat thetotalnumberofhoursapatientexperiencedameanarterial

blood pressure of <60mmHg while on vasopressors was

independently predictive of pressure injury development (Cox andRoche,2015).

3.4.4.2. Diagnosis related to oxygenation and/or

perfusion. Researchers in 10 studies (including four high-quality studies (Slowikowski and Funk, 2010; Cox and Roche, 2015;O’Brienetal.,2014;Cox,2011))entereddiagnosesrelatedto potentiallyaltered perfusion(including diabetes,cardiovascular disease, and peripheral vascular disease) into multivariate modeling (Frankel et al., 2007; Slowikowski and Funk, 2010; CoxandRoche,2015;Suriadietal.,2008;O’Brienetal.,2014;Cox, 2011;Manzanoetal.,2010;Nijsetal.,2009;Tayyibetal.,2015; Comptonetal.,2008);thediagnosesemergedasindependentrisk factorsinsix(Frankeletal.,2007;SlowikowskiandFunk,2010;Cox andRoche,2015;Suriadietal.,2008;O’Brienetal.,2014;Nijsetal., 2009), including allfourhigh-quality studies (Slowikowskiand Funk,2010;CoxandRoche,2015;O’Brienetal.,2014;Cox,2011), onemoderate-qualitystudy,(Nijsetal.,2009)andonelow-quality study(Frankeletal.,2007)(Table2).Researchersintwostudies included sepsis, another condition resulting in altered tissue perfusion, in their multivariate modeling, but sepsis did not emergeasasignificantriskfactor(Manzanoetal.,2010;Compton et al., 2008). In addition, researchers in two studies entered cigarettesmokingintomultivariatemodeling(Suriadietal.,2008; Theakeretal.,2000);smokingwasanindependentriskfactorfor pressureinjurydevelopmentinthehigh-qualitystudybySuriadi etal.(Suriadietal.,2008).

3.4.4.3.Heartrateandmonitoring. Onelow-qualitystudyrecorded heartrateand invasivemonitoringanddeterminedthatneither variable was independently predictive of pressure injury development;however, theauthors recordedvariables onlyfor thefirst24hofapatient’sICUstay,despiteinclusioncriteriathat requiredanICUlengthofstay72h(Comptonetal.,2008). 3.4.4.4. Oxygenation and ventilation. Authors of seven studies entered oxygenation and ventilation-related variables into multivariate modeling (Slowikowski and Funk, 2010; Cox and Roche,2015;O’Brienetal.,2014;Manzanoetal.,2010;Nijsetal., 2009;Tayyibetal.,2015;Comptonetal.,2008);amongthose,one high-quality (Cox and Roche, 2015) and one moderate-quality (Manzano et al., 2010) study identified length of mechanical ventilation as independently predictiveof pressure injury risk. Other oxygenation and ventilation-related variables did not emergeasindependentlypredictive(Table3);however,variable operationalizationlimitsthegeneralizabilityofthefindings:only twostudiesincludedblood-gasresults,andbothstudieslimited their data collection to the first 24h (Manzano et al., 2010; Comptonetal.,2008).Furthermore,mechanicalventilationmaybe more indicative of severity of illness than oxygenation status becauseapatientcouldbestablefromarespiratorystandpointbut stillrequiremechanicalventilationsupportduetootherdisease processes.

3.4.4.5. Vasopressors. Vasopressor infusion is commonly

administered to critical-care patients to improve perfusion in shock states, with resulting peripheral vasoconstriction, which mayconfer risk for pressure injury. (Cox, 2011)Authors of six studiesenteredavasopressorvariableintomultivariateanalysis (Frankeletal.,2007;CoxandRoche,2015;Cox,2011;Nijsetal., 2009;Theakeretal.,2000;Comptonetal.,2008)andinfourof thosestudies,includingbothofthehigh-qualitystudies,(Coxand Roche, 2015; Cox, 2011) vasopressor infusion emerged as independently predictive of pressure injury development (Cox andRoche,2015;Cox,2011;Nijsetal.,2009;Theakeretal.,2000) (Table3).Intheirhigh-quality study,CoxandRoche foundthat patientsreceivingvasopressinwereatincreasedriskforpressure

injury development (Cox and Roche, 2015). Variable

operationalization contributed to difficulty comparing across

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studies.Cox(2011)andCoxandRoche(2015)recordedhoursof administration of specific vasopressor agents and hour/dose, respectively, whereas Nijs et al. (2009) recorded dose but not duration of vasopressor infusion and Theaker et al. (2000) dichotomizednorepinephrineinfusionas“yes/no.”

3.4.5.Domain2subdomain:skin/pressureinjurystatus

The subdomain of skin and pressure injury status includes existingand previous pressure injuriesand general skinstatus. Skin/pressureinjury statusis includedin Colemanet al.(2014) conceptual schemaas a direct causal factor in pressure injury development(Fig.2).

3.4.5.1. Moisture. Moisture is included in skin/pressure injury statusduetoitscloserelationshipwithskincondition(Beeckman etal.,2014).Twostudiesevaluatedmoisture(Theakeretal.,2000; Comptonetal.,2008),anditemergedasanindependentriskfactor forpressureinjuryinonemoderate-qualitystudy(Comptonetal., 2008)(Table3).

3.4.5.2.External skinfactors. Researchers in sixstudiesentered variables related to skin status into multivariate modeling (Slowikowski and Funk,2010; Coxand Roche, 2015;Nijs etal., 2009;Kaitaniet al.,2010;Theakeretal.,2000;Comptonetal., 2008).Thevariablesincludedexternalconditions(incontinence), assessmentoftheskin’sappearance,andedema(Table2).Edema emerged from multivariate modeling in one low-quality study (Compton etal.,2008),butwasnotindependentlypredictiveof pressureinjuryriskinonehigh-quality study(Slowikowskiand Funk,2010),onemoderate-qualitystudy(Nijsetal.,2009),andtwo low-quality studies (Kaitaniet al., 2010; Theaker et al., 2000). Peripheralnecrosisduetovasopressorusewasnotanindependent predictorofpressureinjuryinonestudy(CoxandRoche,2015).A singlestudyrecordeddetailedexaminationoftheskin’scondition (Compton et al., 2008); that low-quality study found that centralized circulation, mottled skin, and reddened skin were independentpredictorsofpressureinjurydevelopment,whereas lividskinandhyperemicskindidnotemergefromthemultivariate analysis(Table2).

3.4.6.Otherfactorsnotincludedindomains1and2

3.4.6.1.Gender. Fourstudiesincludedgenderinthemultivariate model(Cremascoetal.,2013;Kaitanietal.,2010;UlkerEfteliand YapucuGunes,2013;Comptonetal.,2008),andinthreeofthefour (Cremasco et al., 2013; Ulker Efteli and Yapucu Gunes, 2013; Comptonetal.,2008),malegenderwasindependentlypredictive ofpressureinjuryrisk.

3.4.6.2.Risk-Assessmentscales. Overall,sevenstudiesincludeda risk-assessment-scale total score in their multivariate analysis (Slowikowski and Funk,2010;Cox and Roche,2015; Cox,2011; Tayyib et al., 2015; Compton et al., 2008; Fife et al., 2001; Eachempatietal.,2001),andinthreestudies(43%)(Slowikowski andFunk,2010;Fifeetal.,2001;Eachempatietal.,2001)thetotal scoreemergedasanindependentriskfactor(Table3).Thetotal scorefortheBradenScale(BradenandBergstrom,1987)emerged inonehigh-qualitystudy(SlowikowskiandFunk,2010)andone low-qualitystudy(Fifeetal.,2001),and didnotemergeintwo high-qualitystudies(CoxandRoche,2015;Cox,2011)andone low-qualitystudy(Tayyibetal.,2015).

3.4.6.3.Otherfactors. Ahigh-quality studyfoundwinterseason wasariskfactorforpressureinjurydevelopment(Manzanoetal., 2010). One low-quality study noted that increased nursing workloadwasaslightlyprotectivefactor(Cremascoetal.,2013).

4.Discussion

Ourfindingsrevealinconsistentresultsamongstudies,aswell asmarkedvariabilityinstudyquality,indicatingthatresearchers shouldavoidoverinterpretationofresultsfromanysinglestudy. Eachstudywassubjectedtoqualityassessment,whichwillallow cliniciansandresearcherstotakequalityintoconsiderationwhen evaluatingresults.

In the current review of pressure injury risk factors among critical-carepatients, age,mobility/activity,perfusion,and vaso-pressor infusion frequently emerged as important factors in pressure injury development, particularly among high-quality studies.Findingsforageandmobility/activityareconsistentwith theresultsfromasystematicreviewconductedbyColemanetal.in anacute,rehabilitative,long-term-carepopulation(Colemanetal., 2014).Thefindingthatmobilityandpoorperfusionareimportant subdomains is in keeping with current theoretical knowledge, given that mobility and poor perfusion are both direct causal factorsinColemanetal.conceptualmodel;however,results for skinandpressureinjurystatus,whichisalsoconceptualizedasa directcausalfactor,weremixed(Colemanetal.,2014).

Resultsfortheperfusionsubdomainweremixed;however,the bulkofevidencefromhigh-qualitystudiesfavoredperfusionasan importantindependentriskfactor,whereasnegativefindingsfrom lowerqualitystudiesmayhavereflectedmethodologiclimitations. Perfusion isa dynamic process,particularly among critical-care patients, whoareatriskfor hemodynamicinstability.Onlyone study incorporated perfusion-related measures throughout the patient’sentireICUstay(CoxandRoche,2015);otherstudiesthat included perfusion-related variables utilized cut points that

presented dynamic hemodynamic processes as dichotomous

variables, an approach that fails to quantify the magnitude of hypotension.Similarly,onlyonestudyrecordedtheduration of hypotension(CoxandRoche,2015).

Vasopressor agents are an important element influencing perfusionamong ICU patients,but are difficulttostudydue to variability in effects on peripheral circulation related to dose delivered and receptorstargeted.Amongstudies in thecurrent review,onlyonestudyincludedthedoseofthevasopressorforthe entiredurationofadministration,andthesamestudywastheonly onetocapturethepotentiallysynergisticeffectsofmorethanone vasopressoragent(CoxandRoche,2015).Despitemethodological limitations,however,resultsfromthecurrentreviewindicatethat vasopressoragentsareimportantinpressureinjurydevelopment. Among twohigh-quality andone moderate-qualitystudiesthat examined various vasopressor-related variables, all found that vasopressorswereindependentpredictors(CoxandRoche,2015; Cox,2011;Nijsetal.,2009).

Cox and Roche (2015) examined a population receiving vasopressortherapyandfoundincreasedriskamongindividuals receivingvasopressin,whichisimportantbecausevasopressinis

typically considered a second-line drug and is commonly

administered along withnorepinephrine for vasodilatory shock (GordonandRussell,2013).Thisisparticularlyinterestinginlight of a prevalence study conducted by Bly et al. (2016) that determinedthatinfusionofmorethanonevasopressorconferred riskforpressureulcers.1Additionalresearchisneededtoelucidate the effects of individual vasopressor agents, the potentially synergistic effects of multiple agents (particularly concomitant useofnorepinephrineandvasopressin),andtheunderlyingeffects oftheshockstatethatthevasopressoragentstreat.

1

ThestudybyBlyetal.(2016)wasaprevalencestudy,andthereforedidnotmeet inclusioncriteriaforthecurrentreview.

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Coleman et al. conceptual model indicates that skin and pressureinjurystatusaredirectcausalfactorsinpressureinjury development (Coleman et al., 2014). The conclusion that skin statusisimportantisalsosupportedbycurrentclinicalpractice guidelinesandbythebroaderpressureinjuryliterature(National PressureUlcerAdvisoryPaneletal.,2014).Unfortunately,however, informationpertainingtoskinand pressureinjurystatusinthe currentreviewwasextremelylimited;onlyonestudyaddressed skinstatus(exceptingedema)throughoutthehospitalization(vs. only on admission) (Cox and Roche, 2015). Additionally, the authorsof10(56%)ofthe18studiesinthecurrentreviewexcluded patients who were admitted to the ICU with a pre-existing pressureinjury, which isunfortunate, because individuals with provenskincompromisearetherefore notrepresentedinmore thanhalfoftheincludedstudies(Cremascoetal.,2013;Coxand Roche,2015;Suriadietal.,2008;O’Brienetal.,2014;Cox,2011; Kaitanietal.,2010;Theakeretal.,2000;UlkerEfteliandYapucu Gunes,2013;Comptonetal.,2008;Fifeetal.,2001).

Althoughnutrition istheoreticallya factorinpressureinjury development,results fromthecurrent review failedto demon-strateaconnectionbetweennutritionstatusandpressureinjury developmentamongcritical-carepatients.Eachempatietal.study concluded that more days without nutrition conferred risk for pressureinjuries;however,carefulanalysisoftheirstudyshows theopposite(Eachempatietal.,2001).InTable4onpage1681,the 33patientswithapressureinjuryexperiencedameanof1.9days withoutnutrition, whereas the22 patientswithout a pressure injuryexperiencedameanof4.3dayswithoutnutrition. Further-more,thereportedoddsratioof0.51indicatesaprotectiveeffect (Eachempatietal.,2001).Intheirhigh-qualitystudy,Slowikowski andFunk(2010)alsofoundthatpatientsreceivingnonutritionhad alowerincidenceofpressureinjury,buttheychosenottoenter nutrition inmultivariate analysisbecausetheywere concerned that it was a spurious finding, citing Eachempati et al. (2001) erroneousconclusionthatdayswithoutnutritionconferredrisk.In the future, researchers should utilize more sensitive nutrition indictors. Guidance on appropriate measurement of nutrition statusamongcritical-carepatientsisavailablefromtheAmerican SocietyforParenteralandEnteralNutritionincoordinationwith theSocietyofCriticalCareMedicine(McClaveetal.,2016).

Inadditiontoskin/pressureinjurystatusandnutrition,more informationisneededabouttherelationshipbetweensurgeryand therisk for pressure injury development. A high-quality retro-spectiverecordreviewof3225surgicalpatients(notlimited to criticalcare)foundthatmultiplesurgeriesandtotalsurgicaltime wereindependentrisk factors for pressureinjury development (Tschannenetal.,2012).Onlytwostudiesinthecurrentreview includedsurgicalfactorsinmultivariate analysis(O’Brien etal., 2014;Tayyibetal.,2015).

Ourstudywaslimitedtocritical-carepatientswithintheICU setting.Therefore,itispossiblethatwefailedtoincluderesearch thatfeaturedcriticallyillpatientsinothersettings,orsubgroup analysisof studiesthat featuredvariouslevelsof acuityamong hospitalizedpatients. Finally,oursearchstrategy included data-bases that are primarily in the English language—CINAHL (EBSCOhost), the Cochrane Library (Wilson), Dissertations & ThesesGlobal(ProQuest),PubMed(NationalLibraryofMedicine), andScopus—whichmayhavefailedtoidentifysomearticlesin languagesotherthanEnglish.

5.Conclusion

Resultsfromthisreviewofpressureinjuryriskfactorsamong critical-care patients underscore the importance of avoiding overinterpretationofasinglestudy,andtheimportanceoftaking studyqualityintoconsiderationwhenreviewingriskfactors.Age,

mobility/activity,perfusion,andvasopressorinfusionemergedas importantriskfactorsforpressureinjurydevelopment,whereas results for risk categories that are theoretically important, including skin and pressure injury status and nutrition, were mixed (National Pressure Ulcer Advisory Panel et al., 2014). Methodologicallimitationsacrossstudieslimitgeneralizabilityof results,andfutureresearchisneeded,particularlytoelucidaterisk conferred by illness severity, nutrition, and skin and pressure injurystatus.Cliniciansmayconsiderextendingmaximal preven-tiveinterventionstocritical-carepatientswhoareolder, experi-encealteredmobility/activity,havealteredperfusion, orreceive vasopressorinfusions. Future research examining theeffects of poornutrition, andespeciallyskinandpressureinjurystatus,is needed.Inaddition,researchisstillneededtoelucidatetheeffects of specific perfusion related variables, including high doses of vasopressors, combinations of vasopressors, and duration of decreased oxygen delivery to tissues (hypotension and/or de-creasedbloodoxygencontent).

Disclosurestatement

This publicationwas supportedby the National Instituteof NursingResearchoftheNationalInstitutesofHealthunderAward NumberT32NR01345andF31NR014608.Thecontentissolelythe responsibilityoftheauthorsanddoesnotnecessarilyrepresentthe officialviewsoftheNationalInstitutesofHealth.

AppendixA.DatabaseSearchStrategies

SearchLexicon

MH RestrictsthesearchtoMeSHheadingsassignedtothearticle TI Keywordsearchfortermsinthearticletitle

tiab Keywordsearchfortermsinthetitleorabstract

+ Medicalsubjectheadingexplodedtoincludeallnarrowersubjectterms “” Exactphrasesearch

* Wildcard–canreplaceanyletteror,attheendoftheword,multiple letters

su ProQuestsubjectheadings

SearchStatementsEmployed

Database SearchStatement Numberof Results Medline

(EBSCO)

((MH“PressureUlcer”)OR(TI“pressureulcer*”)) AND((MH“intensivecare”)OR(MH“intensive careunits”)OR(TIintensivecareunit*)OR(TI “criticalcare”))

243

Medline (EBSCO)

((MH“IntensiveCareUnits+")OR(MH“Critical Care+"))AND(MH“PressureUlcer+")

334

PubMed (pssureinjur*[TI]ORpressureulcer*[TI]OR pressuresore*[TI]ORbedsore*[TI]ORbedsore* [TI]ORdecubitalulcer*[TI]ORdecubitusulcer* [TI]ORulcusdecubitus[TI]OR“Pressure Ulcer”[Mesh])AND(“CriticalCare”[Mesh]OR “IntensiveCareUnits”[Mesh]OR“Burn Units”[Mesh]OR“CoronaryCareUnits”[Mesh] OR“IntensiveCareUnits,Pediatric”[Mesh]OR “IntensiveCareUnits,Neonatal”[Mesh]OR “RecoveryRoom”[Mesh]OR“RespiratoryCare Units”[Mesh]OR“CriticalIllness”[Mesh]OR “CriticalCareNursing”[Mesh]OR“CriticalCare Outcomes”[Mesh]ORcriticalcare[TI]OR CriticallyIll[TI]ORcriticalill*[TI]ORintensive care[TI]ORcardiovascularunit*[TI]ORcoronary care[TI]ORCardiacCare[TI]ORneurocriticalcare [TI]ORneurointensivecare[TI]ORstep-down unit*[TI]ORstepdownunit*[TI]ORburnunit*[TI] ORhighdependencyunit*[TI]ORneurosurgical unit*[TI]ORsurgicalintensivecare[TI]OR

441 112 J.Alderdenetal./InternationalJournalofNursingStudies71(2017)97–114

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