Lighting, sleep and circadian rhythm: An intervention study in the intensive care unit

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Availableonlineatwww.sciencedirect.com

ScienceDirect

j ou rn a l h o m e p a g e :w w w . e l s e v i e r . c o m / i c c n

Lighting,

sleep

and

circadian

rhythm:

An

intervention

study

in

the

intensive

care

unit

Marie

Engwall

a,∗

,

Isabell

Fridh

a

,

Lotta

Johansson

b

,

Ingegerd

Bergbom

a,b

_,

_Berit

_Lindahl

a

a_Faculty_of_Caring_Sciences,_Work_Life_&_Social_Welfare,_University_of_Borås,_SE-501₉₀_Borås,_Sweden b_Institute_of_Health_and_Care_Sciences_at_the_Sahlgrenska_Academy,_University_of_Gothenburg,_Box_457,_SE

40530Gothenburg,Sweden Accepted4July2015 KEYWORDS Circadianrhythm; Criticalcare; Contentanalysis; Cycledlight;

Intensivecareunit;

Interview;

Mann—Whitney-test; Lighting;

Nursing; Sleep

Summary Patientsinanintensivecareunit(ICU)mayriskdisruptionoftheircircadianrhythm. InaninterventionresearchprojectacycledlightingsystemwassetupinanICUroomtosupport patients’circadianrhythm.PartIaimedtocompareexperiencesofthelightingenvironment intworoomswithdifferentlightingenvironmentsbylightingexperiencesquestionnaire.The resultsindicateddifferencesinadvantageforthepatientsintheinterventionroom(n=48),in perceptionofdaytimebrightness(p=0.004).Innighttime,greaterlightingvariation(p=0.005) was foundintheordinaryroom(n=52).Part IIaimedtodescribeexperiences oflightingin theroomequippedwiththecycledlightingenvironment. Patients(n=19)were interviewed andtheresultswerepresentedincategories:‘‘Adynamiclightingenvironment’’,‘‘Impactof lightingonpatients’sleep’’,‘‘Theimpact oflighting/lightsoncircadianrhythm’’and‘‘The lightingcalms’’. Most hadexperiences fromsleepdisordersand halfhadnightmares/sights andcircadianrhythmdisruption.Nearlyallwerepleasedwiththecycledlightingenvironment, whichtogetherwithdaylightsupportedtheircircadianrhythm.Innight’sactuallightinglevels helpedpatientsandstafftoconnectwhichengenderedfeelingsofcalm.

∗_{Corresponding}_author._Tel.:₊₄₆_733787377.

E-mailaddresses:marie.engwall@hb.se(M.Engwall),isabell.fridh@hb.se(I.Fridh),lotta.johansson@gu.se(L.Johansson), ingegerd.bergbom@gu.se(I.Bergbom),berit.lindahl@hb.se(B.Lindahl).

http://dx.doi.org/10.1016/j.iccn.2015.07.001

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ImplicationsforClinicalPractice

• Mostpatients areawareof the lighting environment,indicating the importanceof adapting lighting topatients’

preferences.

• Lightandlightingwhichfollowanaturalrhythmsupportpatients’circadianrhythm.

• Lightingexperiencesarehighlyindividual.Lightatnightcanbebothdisturbingandprovideafeelingofsecurity.

Background

Thisstudyfocusesonpatients’experiencesandreportsof

beingcaredforinanintensivecareunit(ICU)patientroom,

providedwith a cycled lighting intervention that aims to

supportthepatients’circadianrhythmandhealth.The

cir-cadianrhythmisconstitutedofregulardayandnightover

approximately24hoursandlightanddarknessisimportant

for the human health in supporting the body’s circadian

rhythm(Gaggionietal.,2014;LeGatesetal.,2014).Asearly

as1912Nightingaledescribedlightandtherhythmofnight

anddayastwoimportantfactorsinsupportingandrestoring patient health. Sleep and wakefulness is the most obvi-ouscircadianrhythminhumans(GermainandKupfer,2008) andbothstateshavebeendescribedasbasichumanneeds

by Henderson (1966). The circadian rhythms are driven

bythe circadian pacemaker in the anteriorhypothalamus whichfunctions asthe person’sinner clock (Saperetal., 2004).Exogenousstimuli suchaslightareable tosetthe circadianrhythm inmotion (Veitchetal.,2004). Further-more,lightstimulatestheimmunesystembyregulatingthe pinealneurohormone melatonin(Maestroni,2001),it initi-atestheabsorptionofVitaminD(Masonetal.,2011)andhas beenreportedtoreducethenumberofdaysinhospitalfor patientswithbipolardepression(Benedettietal.,2001).

It is also important to emphasise that light, circadian rhythmandsleepareinterrelatedandinterdependent(Dijk

and Archer, 2009). The presence of nighttime light

sup-pressesthe melatonin level, which is normally highest at night(Duffy and Wright, 2005). The level of melatonin is widely accepted as an indicator for the circadian rhythm

(Benloucif et al., 2005). There are indications that the

constantvariationsincircadianrhythms,duetothe chang-ing hormone levels, experienced by night workers have increasedtheriskofcancer,aswellasinfectiousand autoim-munediseases(Lockleyetal.,2003).

Criticallyillness,lightandcircadianrhythm

Asthemostcriticallyillandvulnerablepatientsarecared for in the ICU it is most important for their survival and health that the environment supports patient restorative processes.Unfortunatelytheordinaryindoorlight environ-ment in ICUs does not always support patients’ circadian rhythms.Lightingissometimesusedathighlevelsatnight, duringtreatments,examinationsandnursingactivitiesand thismayriskdisruptingthecircadianrhythm(Dunnetal., 2010). Mean illumination levels measured in four differ-ent ICUs ranged at night from 2.4 to 145lx and in the

day from55.3 to165lx (Dennisetal., 2010; Frisk etal.,

2004;Meriläinenetal.,2010;Vercelesetal.,2012).These

measurements highlight two main problems, a pattern of lowilluminationlevelsbydayandhighlevelsbynight.

TheICUpatients’nighttimesleepisdescribedas abnor-mal and fragmented with reduced periods of REM sleep

(Elliottetal., 2013).Light inthe nightis oneknown

fac-torforsleepdisruptionwhenitimpairsmelatoninsecretion

(Kamdar et al., 2012). Circadian rhythms are temporally

disturbed in most ICU patients; some develop temporal disorganisation andthe circadian pacemakermay become effectivelyfree-running(Frisketal.,2004;Gehlbachetal.,

2012;Perras etal.,2007).Furthermore,sleepdeprivation

isoneimportantriskfactorforICUdelirium(Girardetal., 2008). Patients’ vulnerability increases withlack of sleep andarecharacterisedbyincreasedsensitivitytolight,noise andactivity(McKinleyetal.,2002).The health,wellbeing andrecovery ofpatients aredependent upontheir ability togetanormalsleepandcircadianrhythm.Mostresearch into light environments affecting the circadian rhythm in anICUcontexthasbeen donewithinfants(Engwalletal.,

2014; Moragand Ohlsson,2011).Based onthe knowledge

concerninglightanditsimportancetothecircadianrhythm itwouldseemimportanttomeasureandthenevaluateand reportpatients’experiences.

Aims

This study consisted of two parts: in Part I, the aim was to evaluate and compare patients’ experiences of light-ingenvironmentsin twoICU rooms withdifferent lighting environments;inPartII,theaimwastodescribepatients’ experiencesofanICUroomequippedwithacycledlighting environment.

Method

This studywasapartofalargerstudyconcerningpatient experiences ofthe ICUenvironment withregardtosleep, restandcircadianrhythms(Engwalletal.,2014;Johansson etal., 2012). Part Iwasa comparative,descriptive study whichincludeddatafromaquestionnaireusedtocompare twopatient groups, oneexposed toa cycled lighting sys-tem and the other to an ordinary lighting system. Part II had an explorative and descriptive design based on data derivedfromnineteeninterviews,subjectedtoqualitative andquantitativecontentanalysis(Krippendorff,2004).

Setting

The studywasconductedinan eight-bedgeneralICUin a regional hospital in Sweden in which a new cycled light-inginterventiondesignedtopromotecircadianrhythmand

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Table1 Scheduleconcerning14 differentlightscenesin periods and illumination levels in the intervention room. IlluminationlevelinluxmeasuredinJanuary2012. Lightscenes

inthe intervention room

Time Illuminationlevelsin luxinhorizontal planeatthepatients headinJanuary2012, interventionroom 1 7—8am 58 2 8—10am 615 3 10—10.30am 450 4 10.30am—1pm 330 5 1—3pm 210 6 3—5pm 450 7 5—6pm 330 8 6—7pm 210 9 7—8pm 81 10 8—8.45pm 58 11 8.45—9pm 30 12 9—9.15pm 12 13 9.15—9.30pm 8 14 9.30—7am 2

healthwasinstalledandusedinamodiﬁedtwo-bedpatient

room (intervention room). An identical two-bed patient

roomwasleftuntouchedforcomparison(ordinaryroom).

In the interventionroom, acycledlighting system was

developed in cooperation with an expert in

environmen-tal psychology andlightingengineers. The lightingsystem

aimed to simulate natural light regarding localisation,

brightnessandcoloursoflight,workedin14differentlight

scenesthatwere allcontrolledautomaticallyby software

roundtheclock.Thelightsourceswerelocatedatﬂoorlevel

andonwallsandalightﬁtmentprovidingindirectlighthung

down45cmfromtheceiling,shiningupwardinordernotto

blindthepatient.Thecolouroflightvariedintwo

differ-enttubes(2700Kand6500K)shiningfromthelightﬁtment.

The day lighting lasted from 07.00 to19.00hours.In the

morning,awarm,low-levellightstartedthedayandwith

a continued brighter morning period that aimed towake

and alert the patients. At noon the levels became lower

anddaylightshonethroughthewindows.Inthe afternoon

thelightinglevelswerehigheragainandintheeveningthe

samewarmcolourandlow-levellightingasinthemorning

wasrepeated.By night,light levels wereevenlower and

Table2 Lightsettingsinilluminationlevelsintheordinary room.IlluminationlevelinluxmeasuredinJanuary2012. Differentlight

sourcesin comparisonroom

Illuminationlevelsinlux inhorizontalplaneatthe patientsheadinJanuary 2012,comparisonroom Lightingsatwall 147 Lightingsinceiling andwalls 810 Nightlamps 0.7

onlythelight sourcesnear theﬂoorwere used.The staff

thenusedlocalisedlightingforworkwhennecessary.Inthe

two-bedordinaryroomwhichwasusedasacontrolthelight

sourceshadbeen installedin1992 andthe staffswitched

thelight onand off manuallyaccording totheir ownand

thepatients’preferences.Bothroomsfeaturednorth-facing

windowswhichletindaylightandprovidedaviewofagrassy

slopeaswellasasmallglimpseofthesky.Lightlevelswere

measuredateachlightsettingintheinterventionroomand

ateachlight sourceinthe ordinaryroom(Tables1and2,

Engwalletal.,2014).

Participants

and

procedure

Patients,whowereadmittedtotheICU,wereassignedto one of the two rooms according to patient ﬂow. If beds inbothroomswereavailable, patientswereassigned ran-domly. In some cases, the patient’s health condition and special needs aswell as the number of staff determined whichroomthepatientwasallocatedto(Fig.1).

Inclusioncriteriaforcompletingthequestionnaire(Part I)werecompetenceinthe Swedishlanguageanda stable health condition. Exclusion criteria were the presence of psychosis,dementia,blindness,heavybraininjuriesor test-ing positive on Confusion Assessment Method for the ICU (CAM-ICU).DemographicdataispresentedinTable3.

Inclusioncriteriaforparticipatingintheinterviewstudy (PartII)wereplacementintheinterventionroomforatleast twonights,competenceintheSwedishlanguage,abilityto rememberthepreviousnightsandbeinghealthyenoughto copewithaninterview.Exclusioncriteriawerethesameas describedabove.Theﬁrstauthorvisitedthepatientsinthe ICUorshortlyafterdischargeinthegeneralward.Patients healthy enough to copewith an interviewwere asked to participate.Atotalof19patientstookpart;twodeclined participation(Table4).Twelveofthe19patientsboth par-ticipatedintheinterviewsandansweredthequestionnaire. Sevenofthe19patientswereonlyabletoparticipateinthe interviews,conductedafterdischargefromtheICU. Their poorhealthsituationpreventedthemfromcompletingthe questionnaire(Fig.1).

Duringtheperiodofdatacollectionaprotocolwas com-pleted,includingallpatientsadmittedtooneofthetwo-bed rooms.Excludedandincludedpatients,demographics,type ofdatacollection, placeandperiodofcare, deaths, con-sentand dischargewere allnoted.Therewere signiﬁcant differences(Table5)betweenpatientsincludedinthestudy andthosewhowereexcludedinrelationtoSimpliﬁedAcute PhysiologyScore(SAPS)andnumbersofmechanically venti-latedpatients.

Data

collection

Part I comprises data collected by means of a writ-tenquestionnaire,developedbyenvironmentalpsychology researchers(KüllerandLaike,1998;KüllerandWetterberg, 1993).Itconsistsof17dichotomous,semantic,seven-grade scales and when using different adjectives it focuses on experiencesoflightingenvironments.Anexampleofanitem fromthequestionnaireisshowedinFig.2.

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at the ICU, from August 2012 to May 2014.

Missed due to nights, weekends and holidays (n=99).

Excluded due to inclusions criterias (n=60). Deaths (n=12).

No signed agreement (n=7). in part II.

7

12

Figure1 Flowchartofpatientselection,PartsIandII.

Table3 Demographic data (numbers ofpatients, age,sex, SAPSandmechanically ventilation) andcomparisons between patientsintheinterventionandtheordinaryroom,inthedayandnight,PartI.

Patientsinthe intervention group,day Patientsin theordinary group,day p-Value, day,t-test. Signiﬁcant value,<0.05 Patientsinthe intervention group,night Patientsinthe ordinarygroup, night p-Value,night, t-test.Signiﬁcant value,<0.05 n 45 50 17 13

Ageinyear,mean 60 62 0.491 63 64 0.844

Genderratio, men(n)

24 25 0.838 12 10 1.000

SAPSscore,mean 51.07 47.74 0.345 52.47 53.46 0.819

Mechanically ventilated(n)a

25 23 0.413 10 6 0.713

a_Number_of_patients_using_invasive_or_noninvasive_ventilation.

Thequestionnairewasusedtocomparepatients’ experi-enceofthelightenvironmentintheinterventionwiththat in theordinary room. Reliabilitywastested and revealed fourorthogonalcomponentsnamed; hedonictone, bright-ness,variationandﬂicker.Thequestionnairehaspreviously beenusedinresearchwithhealthypeople(KüllerandLaike,

1998).

Theassessmentofthelightenvironmentwasperformed inthepatient’sroomattheendoftheirstayintheICUor whentheywereabletoparticipate.Thequestionnairewas administeredbynursingorresearchstaffandcompletedby

Table4 Demographic data(numberofpatients,sex and age,mechanicallyventilated),PartII.

Patientsinthe interventionroom

n 19

Ageinyear,mean 65

Genderratio,men(n) 13 Mechanicallyventilated(n)a ₁₆

a_Number_of_patients_using_invasive_or_noninvasive_ventilation.

thepatients.Sometimesthepatientswerehelpedwiththe writing.Thequestionnairetookaboutﬁvetotenminutesto complete.ThedatawerecollectedfromAugust2012until May2014.

In Part II, semi-structured interviews supported by an interviewguidewereusedtogainadeeperunderstanding of the patients’ experienceof the light environment and circadianrhythm(Fig.3).Interviewswereconducted imme-diately prior toor after patients’ discharge fromthe ICU tothegeneralwardandvariedinlengthfromﬁvetoforty minutesdependingonthepatients’experiencesandhealth. Theinterviewswererecordedandtranscribed.Onlypatients fromtheinterventionroomwereincludedintheanalysisas theresearchers’wereinterestedinpatientexperiencesof thecycledlightingenvironment.Theseinterviewswere con-ductedinJanuary2013andfromSeptember2013untilApril 2014. The patientsweredrawn fromthedataset (n=194) and(n=100)basedoninclusioncriteria(Fig.1).

Analysis

PartIshowsscoresandmeanvaluesforeveryfactorwhich were statistically analysed (IBM software® _SPSS ₂₁₎ _using

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Table5 Demographicdata(numbersofpatients,age,sex,SimpliﬁedAcutePhysiologyScore(SAPS)andmechanicalventilation) comparisonsbetweenincludedandexcludedpatients,PartI.

Patientsinthe inclusiongroup Patientsinthe excludedgroup p-Value,t-test. Signiﬁcantvalue,<0.05 n 100 281

Ageinyear,mean 61 60 0.431

Genderratio,men(n) 52 168 0.195

SAPSscore,mean 49.40 55.19 0.011

Mechanicallyventilated(n)a ₅₀ ₁₉₃ _0.001

a _Number_of_patients_using_invasive_or_noninvasive_ventilation.

How do you experience the light in this room? Select by ticking the following scale:

Dark Light

Figure2 Anexampleofanitemfromthequestionnaire,Part I.

theMann—Whitneytesttocomparepatients’lighting expe-riencesbetweenthetworooms,bothbydayandatnight.

The interview data in Part II, were subjected to both quantitative (Krippendorff, 2004) and qualitative conven-tional(HsiehandShannon,2005)contentanalysis,focusing onthetext’ssubjectivecontent.

Thetranscriptswerereadseveraltimes;wholenesswas soughtandmeaningfulconceptsnoted.Codeswerecreated whichdescribedsmallpartsofthecontentoftheinterviews. The codes were then assembled in one document andby identifyingandcomparingsimilaritiesinthecodestheywere putintodifferentclusterslinkedtoeachotherbycontent. These clustersformedsubcategories which described sim-ilarcontentandwerethen organisedintocategories.This processwascreatedinductivelyandkeptclosetothe trans-cripts to ensure credibility. There was a quantifying part

in the analysis process asﬁve questions in the interview guidecouldbeansweredwithyesorno.Theseresultsare presentedseparately.

Ethical

considerations

EthicalapprovalwasgivenbytheRegionalUniversityEthics ResearchCommittee(no695-10).TheHelsinki declaration ofEthicalPrinciples forMedicalResearchinvolving human subjectsguidedthestudy(WorldMedicalAssociation,2013). Patientsreceivedbothverbalandwritten informationand wereinformedoftheirrightsasvoluntaryparticipantsprior toprovidingwritten consenttoparticipationinthe study. Patientswereaskedtoparticipatewhentheirhealth situ-ationwasstable:atthebeginning,middle orend oftheir stay.Researchersevaluatedthepatients’abilityto partic-ipateregardingtheirhealthsituationincollaborationwith theICUheadandtheallocatednurse.Patientsweretreated sensitively and the data collection was ended if patients wereunabletocompletequestionnairesorinterviews.Every dayintheperiodofdatacollectiononeoftheresearchers wasresponsiblefor the processat theICU. Patientswere admittedto the ICU around the clock and were asked to participateassoonasitwaspossible.

1. How have you been sleeping in this room during the nights here in the ICU?

2. How has it been for you to fall asleep?

3. Have you been afraid to go to sleep?

4. Have you woken up during the night?

5. What or who woke you up?

6. Do you remember anything that happened during the nights here in the ICU?

7. What feeling do you get when you think of the nights here in the ICU?

8. Have you had any dreams or visions?.

9. What help did you get to sleep?

10. Did you sleep here in the room during the day?

11. What was sleep during the day like?

12. Did you feel rested during the day?

13. How do you sleep at home?

14. How have you kept track of the time during the day?

15. How have you been able to keep track of the morning, afternoon, evening and night?

16. How have you distinguished between day/night?

17. What time of day is it now?

18. What do/did you think about the lighting in the room?

19. Did the light vary during the day? If yes, describe how.

20. What did you think of the brightness at night? Did the light disturb your sleep?

21. Was it light enough for you to feel safe during the night?

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Table6 Patients’assessmentofthelightenvironment,PartI. Factor Intervention room,day Ordinaryroom, day Mann—Whitney-test Intervention room,night Ordinary room,night Mann—Whitney-test

Mean Mean p-Values

signiﬁcant

p-value,<0.05

Mean Mean p-Values

signiﬁcant p-value,<0.05 Hedonictone 5.18 4.94 0.280 5.28 5.01 0.166 Brightness 4.75 4.07 0.004 3.84 3.73 0.619 Variation 3.95 4.00 0.564 3.50 4.58 0.005 Colour 3.65 3.22 0.325 3.40 3.64 0.753 Flicker 2.26 1.94 0.415 2.15 2.55 0.128

Table7 Patients’experiencesofsleep,nightmares/visions,circadianrhythmandpleasedwiththecycledlightingenvironment, PartII.

Participants Sleptbadly intheICU Sleptbadly athome Experiencesof nightmaresor/and illusions Experiencesof disturbedcircadian rhythm

Pleasedwiththe cycledlighting environment

N=19 11/18a _4/17b _9/19 _9/19 _16/17b

a_One_patient_missing. b _Two_patients_missing.

Results

Theresultsfromthequestionnaire(PartI)arepresentedin

textandinTable6.

Lightingexperiences,PartI

Thequestionnaireinvolved100patients(Fig.1)caredforin oneofthetworoomswhocompletedatotalof95 assess-ments in the daytime and 30 at night; i.e. 25 patients completed assessments for both day and night. A signiﬁ-cant differencewasfound between lighting environments inthetworooms’forbrightness(p=0.004)inthedaytime, favouringtheinterventionroom.Therewasasigniﬁcant dif-ference(p=0.005)forvariationbetweenthetworoomsat night,indicating greater lighting variationin theordinary

room(Table4).

Lightingexperiences,PartII

Whenanalysingtheinterviews,ﬁvequestionsfromthe inter-view guidecould be answered withyes or no. The result indicated that nearly all the patients were pleased with the lighting environment in the intervention room. They sleptworseintheICUthanathome.Nearlyallthosewho experienceddisruptedcircadianrhythmalsohadnightmares

(Table7).

The analysis of the interviews is presented in text in thefollowingmaincategories(headings)andsubcategories (underlined)(Table8).

Adynamiclightingenvironment

This category describesexperiences suchaspleasantness, levelsof lightingsand variation. Most, but notall, of the patientscouldtalkabouttheirmemoriesandexperiencesof

Table8 Patients’experiencesoflighting/lightintheinterventionroompresentedincategoriesandsubcategories,PartII. Adynamiclightingenvironment Impactoflighting

onpatients’sleep

Theimpactof

lighting/lightsimpacton thecircadianrhythm

Thelightingcalms

Pleasantandhealthy lightings

Bothpoorandgoodnight timesleep

Diverseperceptionsof theregularityofdayand night

Anxietyandsearching forsecurity

Acceptablelighting levelsatnights

Levelsaffectingsleep Disturbingimpact Severeanxietyreplaced bycalm

Variationsinthelighting roundtheclock

Supportingimpact Thelightingclarity createdsecurity

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thelightingandthedaylight,bothinthedayandatnight;

othershadonlysporadicmemories.

Patients who recalled the light environment generally

talked about apleasantandhealthylighting environment,

asonepatientsaid:

‘‘Itwasnice,itwasnotsharpanditwasapleasantlight’’

No23.

The lighting affected their wellbeing and health

posi-tively.Theclearmorninglightwasimportantasitincreased

alertness andaffectedtheirmood inagoodway. Lighting

wassometimestakenforgrantedandthepatientshadnot

alwaysreﬂectedonitduringtheirstayintheICUbutthey

wereabletocompareitwithanotherlightingenvironments

e.g.oftenthelightingenvironmentathomebutalsothaton

otherhospitalwards,includingtheonewheretheinterview

wasperformed.Onepatientsaid:

‘‘Ityouthinkback,itismuchmoreupliftingtobeinthat

light(attheICU)thanthis(onageneralward).’’No8.

Several patients recalled that there were

acceptablelightinglevelsatnight. It was not completely

dark but more like twilight. Most did not experience the

lightlevelsatnightasdisturbingalthoughtheywereaware

thatthelightwasbrighterthanathome.Onepatientsaid:

‘‘Itisobviousthatitwasquiteabrightlightbutwedonot

havecompletedarknesswherewesleepeither...itdoes

nothurtme tosleepin half-brightlight,sotospeak’’.

No14.

Lightinglevelswereassessedasacceptable.Therewere

patientswhowantedbrightersurroundings.Someassessed

thelighting levelsasalmosttoohigh buttheyunderstood

that the levelswere a compromise. The room in the ICU

was notonly a placefor patients; it was also a placeof

workforstaffandthepatients’demandsconcerninglighting

levelsthatwerenottheonlyimportantissue.Asonepatient

expressedit:

‘‘Itcouldhavebeendarker,butthestaffmustbeableto

worktheretoo’’.No9b.

Experiences ofvariationsinthelightingroundtheclock

werealso described.There weredifferent opinionsabout

whether the lighting varied between day and night and

duringtheday.Someofthepatientsexperiencedclear

dif-ferencesinthelighting betweenday andnight.Theyalso

noticedthatthelightwasdimmed duringtheeveningand

became darker at night.The variations in lighting during

thedaywerehardertodetect.Afewreportedavague

feel-ingabout changes in lightinglevelsand colourduring the

day.Thetransitionsbetweenthedifferentlightsceneswere

softandun-disturbing.Mostdidnotnoticethetransitions

butinsteadthoughtthatthelightingfollowedthedaylight

outsidethewindows.Onesaid:

‘‘Yes ithas varieddependent on howit wasoutside, I

havenoticedthatat7(pm)whenitstartedtogetdark

outside,atthesametimeitgotdarkerinsidetoo,itwas

probablysomekindofcombination’’.No23.

Impactoflightingonpatients’sleep

Thiscategorydescribes’experiencesofsleepandhowlight

isrelatedtosleep.Patientsemphasisedtheimportanceof

sleep,forrecoveringandregaininghealth.

Bothpoorandgoodnighttimesleep was experienced.

Patientswhoreportedpoor sleepqualitymentioned

difﬁ-cultiesgettingtosleep,nightswithnosleepatallornights

withfrequentwakeningsandwithfragmentedsleep.

‘‘Bad,Ihaveonlysleptforperiodsof30to45minutes,

thenIwaswokenup.Ithasnotbeenanevensleep,one

ofthelongestnightsforages’’.No26.

Othersfelttheysleptwell:

‘‘Yesrelativelywell,Ihavetosay.No27.

Lightinglevelsaffectedtheirsleepbutthepatientshad

different opinions about the lighting levels in relation to

sleep.Someofthemwanteditdarkerwhileafewwantedit

brighter.Mostfeltthatthelightinglevelswereappropriate.

Itwasnotsobrightthatitwasdisturbingbutbrightenough

toorientatethemselvesintheroom.Onesaid:

‘‘...itwasgoodthatyoucouldseealot,andyouwere

notinsideadarksack,sotosay’’.No22.

Somepatientscurrentthepresentlightinglevelstothe

abilitytosleep.Thelightingcouldbeonereasontheirsleep

wasdisturbed.Onepatientsadaboutsleep:

‘‘Abysmal,thankstoitbeingsobright.’’No19.

Otherpatientsthoughtthatthelightinglevelswere

mod-erateforsleepingin.Thefactthatthepatientswereableto

talkabouttheirexperiencesandsawapositiveconnection

betweensleepanddarknesswasclariﬁedintheirreﬂections

concerningsleepandrestduringtheday.Mostofthemhad

sleptonandoffduringthedaydespitethedaylightandthe

lightingandweresurprisedaboutthis.Asoneexpressedit:

‘‘Youhavetakeniteasy,evenifthelightwasswitched

on,youweresotiredthatyoucouldjustcloseyoureyes

forawhile,thenyoufellasleep’’.No23.

Theimpactoflighting/lightsonthecircadianrhythm

This category describes patients’ experiences concerning

circadianrhythmanditsrelationshiptolight.

Thepatientshaddiverseperceptionsoftheregularityof

dayandnight.Forsomeitwashardtokeepanormalrhythm

whichinturnledtobeingconfusedabouttimeandtheloss

oftheabilitytodistinguishbetweendayandnight,which

wasperceived asvery difﬁcult. Another interviewee also

mentionedthissaying:

‘‘NoIhavenotbeenabletodothat,forexampleinthe

night when theytold me that thetime was2 am....it

cannotbetrue,itisinthemiddleoftheday’’.No6.

Otherswerecompletelyorientedastotimeandit was

completelynatural andeasy forthemtoseparatedayand

night.Onerelatedtheabilitytoseparatedayandnightto

hishealthsituation,saying:

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Lighting’s disturbingimpact on the circadian rhythm

whenitwasswitchedonbythestaffduringthenight,was

reportedandexpressedasfollows:

‘‘Whenthelightwasswitchedon,Ididnotknow(ifitwas

dayornight)becauseitwasbasicallythesamelight’’.

No13.

Thelightinglevelswereconsideredlowbutatthesame

timebrighterthanathome.Thiswasperceivedbyafewas

disturbingthemaintainingofthecircadianrhythmandone

said:

‘‘It was a good lighting environment, without dazzle.

Thenthelighting wasreducedat 10pm,Ithink,butit

didnothelpme(toorientateaboutdayandnight)’’.

In answer tothe question about whathelped to

main-tainanormalcircadian rhythmthelightinginsideandthe

daylightsupportingimpactofthewindowswerementioned.

Bothlight and darkness were important for the circadian

rhythm.Answeringaquestionabouthowithadbeenpossible

todistinguishbetweendayandnightonepatientsaid:

‘‘It is the light and everything, the sun is shining

outside...Yes and when the lights were turned up and

downIwasabletofollow(thedayandnight),ohyes...’’.

No9

Thelightingcalms

Thiscategorydescribesexperiencesofanxietyorsecurity.

The following descriptionsshowhow thelighting clariﬁed

theenvironmentandhowanxietywasalleviatedbylight.

Patients often experienced

anxietyandsearchedforsecurity in their surroundings.

Theyponderedmoreover theirhealth situationand

prog-nosis at night and their thoughts could sometimes result

infeelingsof anxietyandfearof losingcontrol overtheir

situation.Onepatientsaid:

‘‘Yes,itwasanight,thesecondorthethird,whenyou

thoughtthat.ThenIhad alotof painandsleptbadly,

whathashappening?Isthisthewayeverythingwillend?

No14.

Others felt secure in spite of the unfamiliar

environ-mentandtheirvulnerablesituation.Thepatientsconnected

to their inner security, which they felt was independent

of the surrounding environment. The lighting

environ-ment alsoaffected their possibilityof feeling secure and

the light allowed severeanxietyreplacedbycalm. Some

patients had been totally terriﬁed during the nights but

therewere alsothose whofelttrust andhad been calm.

Anolderpatientrememberedhowhismothergotthe

chil-drentosleepintheevening,byleavingthelightsswitched

on.Severeanxietywasalleviatedbylightduringthenight.

Duringthemostworrying period,abedside lampcould

beused.This contributed tofeelingsof calmness, asone

patientsaid:

‘‘....Itgotbetterwhenthelightwasswitchedon.Itfelt

moresecureinaway’’.No13.

Mostofthepatientsconsidered thelightinglevelshigh

enoughforthemtofeelsecure.

Despitetheroombeingwell-litsomepatientsfelleasily

asleepandsleptwell duringtheday.Somedescribed that

theyslept, onandoff; the light wasnotdisturbing; staff

werearoundthemandtheyfeltsecure.

Thelightingclaritycreatedsecurity by lighting up the

surroundings. Light was a prerequisite for perceiving the

surroundingobjectsintheroominarealisticway.Fearand

anxietycouldoccurwhenthepatientswereunableto

ori-entatethemselvesintheroom.Thelightinglevelsenabled

themtoseeandidentifythestaff.Thestaffplayedan

impor-tantroleincreatingcalminthepatientsandbeingableto

see them and have aface tofocus onwascomforting. It

conﬁrmed that they existed and that someone wasthere

andabletohelpthem.Onepatientexpressedthis:

‘‘...security were moreabout seeingthe staff...’’.No

19.

Discussion

Reﬂectionsontheﬁndings

Thisstudydoesnotshowclearlythatthecurrentlight

inter-ventionaffected suchfactorsasmaintenanceof circadian

rhythm withsubsequent beneﬁttothe patient’srecovery.

However,developingknowledgeaboutpatientexperiences

oflightenvironmentsandtheirrelationtocircadianrhythm

andhealthisanimportantstartingpoint.Thepresentstudy

showsthatpatientscouldthinkaboutandassesslight

envi-ronments despite severe illness and complex treatments.

This is animportant result.Ourﬁndingsindicate acycled

light system in advantageous and that people

continu-ouslyinteractwiththeirsurroundingenvironment(Olausson

et al.,2013; Rashid, 2006). Light is one importantfactor

inthisandourﬁndingsaremeaningful,butmoreresearch needstobedone.

The results from the questionnaire showed signiﬁcant differences in favour of the intervention room regarding factorforbrightnessindaytime.Thisfactorcomprisedthe adjectiveslight,weak,drabandbrilliant.Accordingto pre-vious knowledge, itis importanttoget bright lightin the morningandinthedaytimetostartupandsupportthe cir-cadianrhythm.Brightlightinthemorningincreaseshuman alertnessandmood,bysuppressingthehormonemelatonin (highestinthenight)andincreasingcortisol,thehormone of alertness (Chan etal., 2012; Fiigueiro andRea, 2010). Thesechangesinhormoneactivityduetolightlevelsareone importantpart ofthecircadianrhythm whichinturn sup-portshealth.Resultsfrompreviousmeasurementsoflightin theinterventionroomreportedluxvaluesas615between

8and10am(Table1,Engwalletal.,2014).Togetherwith

thepresentstudy’sresultsitindicatethatthecycled light-ingenvironmentbettersupportpatients’circadianrhythm thanthelightingenvironmentintheordinaryroom.Inthis roomonlythelightingatwallnormallywereswitchedonin daytimeandheretheluxvalueswereonly147.Lightingsin ceilingandwallsreportedvaluesat810lx(Table2).These highvaluesoflightwerenormallyonlyafactwhenspecial examinationswereperformed.

The patients in the ordinary room were also able to detectdifferencesinvariationsofthelightingdistributions

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atnighttime(8—8.45pm)andassessedthelighting environ-mentasmorevarying.Thefactorforvariationcomprisedthe adjectives concentrated, evenly distributed and focused. The patients maybeidentiﬁeda coupleof differentlight sourcesthatspreadthelightin ashiftingway.Incontrast to the intervention room where the indirect light spread the light more uniformly, as here shone upwards in the ceilingand on thewall. A smooth,well distributed light-ing environment without partsof dark shadows andglare is recommended and is more comfortable for individuals

(CanadianCentreforOccupationalHealthandSafety,2014).

The intervention room is not only a place where the patientcanrestandrestore.Itisalsoaplacewherethestaff shouldbeabletoworkandthelightlevelsshouldpromote writingandallowassessmentofpatients’conditionsandbe abletoreadandwatch overthetechnologicalequipment. Patientswereawareofthissituationwhentheyassessedthe lightlevelsatnightasacompromise.Inspite ofimpaired healthconditiontheyinteractedwiththephysical environ-mentandthestaffandwereabletoprioritiseothers’needs beforetheirown.Onewaytoovercomecompetinglighting demands is to includepatients, staff and relatives in the designprocedure(Perkins,2013).

Most patients reported that their sleep was worse in the ICU than at home. This corresponds with previous research (Littleet al., 2012) where light was one of ﬁve mostfrequentlycitedreasonsforsleepdeprivation.These researchers proposed nocturnal modiﬁcation such as dim lightthat canbecomparedwithourcycledlighting inter-vention.

Nineintervieweesreporteddisruptedcircadianrhythm. This is also well-known from previous research (Verceles et al., 2012). Eight of these nine patients also reported nightmares or visions and seven slept badly and were mechanically ventilated. Sleep disorders, nightmares and disrupted circadian rhythm are present in patients with ICU delirium and previous research shows that 60—80% of mechanically ventilated patients and 20—55% of non-ventilated ICU patients with experiences from delirium

(Pisanietal.,2009;Thomasonetal.,2005).

Patients’ inner clocks were perceived as being incon-sistent withclock time, a knowneffectof light exposure betweenmidnightanddawninmammals(Hutetal.,1999), asitturnstheinnerclockbackwards.Earlierresearchshows that brighterlight affectsthe inner clock more than dim light(Duffyetal.,1996).Somepatientsinthepresentstudy reportedverydisturbedinnercircadianrhythmsaswellas lightexposureatvariouspointsthroughthenight.The light-ing levels also, however had a comforting effect on the patientsinthenightastheycouldseeandrelatetostaff. This ﬁndingisin agreementwithstudies inan emergency wardwherepatientssaidthatseeingthenurseenteringthe roomincreasedtheirsenseofsafetyandsecurity(Shattell

etal.,2005).

The cycled lighting environment based on scientiﬁc researchconcerninglight,circadianrhythmandhealthwas reportedaspleasantby16/17 interviewed.Froma caring perspectiveit is importanttoreﬂect onpatients’ individ-ual experiences. It is important with a balance between supporting the circadian rhythm by lighting and making patientsfeelsafeandcomfortable.Themostpositivewayof designingalightingenvironmentmightbetoallowpatients

to decide individually about in the lighting environment tomeet theirrequirements (Thompson etal., 2012). The patient is in many ways the caring expert and it is very important that their preferences should guide the caring process(Coulter etal., 2008).It is alsopossible that dif-ferentdiseasesandhealthconditionsmayrequirediffering light environments. In the future, the ability to individu-aliseanenvironmentallightingprotocoltomeettheneeds ofeachpatientwouldbeidealin creatingamore healing environmentintheICU.

Knowledgeaboutpatients’perceptionsandexperiences oflightenvironments,togetherwithphysicalmeasurements oflightinganddaylight’sroleinestablishingthecircadian rhythmareconsideredusefulforfutureresearch.

Criticalreﬂections

Two differentmethodological approaches were used. The questionnairehasbeenusedin previousstudies butisnot designed speciﬁcally for ICU environments. The 17 ques-tionswererelativelyeasytocomplete butpatientfatigue andreduced ability to concentrate could bea weakness. However, many patients completed the questionnaire by themselvesoraskedtheresearcherforsupplementary infor-mation.Mostofthepatientsweretiredandexhaustedwhich precludedopen-endedinterviews.Aninterviewguidewith shortandsimplequestions(KvaleandBrinkmann,2009)was usedasmoresuitedtothepatients’conditionandabilityto narratetheirexperiences.Onepatientwasabletonarrate spontaneouslywithoutsupportfromtheinterviewguide.In other cases thequestionnaire worked well in relation for itspurpose.Contentanalysiswasfoundusefulforanalysing relativelyshorttranscriptions.

Somepatientsusedtheinterviewsasachancetovoice their ICU experiences in general. Interviews may have a supportingfunctioninprovidingthepatientswiththe oppor-tunity to have somebody listen who is familiar with ICU careandthusabletounderstand(NordentoftandKappel, 2011).The interviewer (ME) is experienced inprehospital andcriticalcareandtheotherresearchers,apartfrombeing experienced in intensive care, arealso familiar with ICU research.Interviewsallowfollow-upquestionstobeasked, giving a deeper and clearer understanding. Today’s seda-tionpracticeshavemovedfromadeepertowardsalighter sedationregimen.Thisissomethingtoconsideraspatients aremoreawakeandthussensitivetothesurroundingspace

(Egerodetal.,2013).

Allocationof patientstothetworoomswassometimes determinedbytheirspecialneedsintheICU.However,no signiﬁcantdifferencesbetweenthetwogroupswerefound inrelationtosex,age,useofrespiratorandSAPS.Thismade itpossibletocomparethetwopatientgroups’experiences oflight.

The participants represented various ages, had severe differentdiseasesortraumasandhadundergoneindividual treatments involving the use of potent drugs. Extra pro-tection was given, in terms of a sensitive approach and collaboration with staff and next of kin, when planning andcollecting the databecause of the patients’ vulnera-bilityandtheincreasedriskofpersonalharm(Liamputtong, 2007).Themostcriticallyillpatientscouldnotbeincluded

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inthestudyastheywereunabletocooperate.Theywere includedintheexclusiongroupandhadsigniﬁcantlyhigher SAPSvaluesandmechanicalventilatoruse(Table3). Unfor-tunatelythisgroup’sexperiencesweremissed.Theresearch group had joint discussions concerning the analysis. The quotationsin the result section arean expression of the authenticityoftheparticipants’statementsandthecontext

(EloandKyngäs,2008).

Conclusions

Manyof the patientsin the ICU had experiences of sleep disordersanddisruptedcircadian rhythms. Acycled light-ing system that copied the natural light was considered important and was assessed as pleasant and together with daylight, supported for the circadian rhythm. Most patients were aware of and able to assess light environ-mentseveniftheyhadexperiencesfromcriticalillnessand treatments.Appropriatelightinglevelsintheenvironment helpedpatientsandstafftoconnecttoeachother, which engenderedfeelingsofcalmandsecurity.

Acknowledgements

Thanks to Fagerhults Lighting AB for constructing and installing the cycled lighted system, Annelie Ryberg, Anna-KarinWindellandEwaLagerströmforexcellenthelp with the data collection, Göran Jutengren for important guidance regarding statistics and Pat Shrimpton for the languagereview.

Funding

Theauthorshavenosourcesoffundingtodeclare. Conﬂictofintereststatement

Theauthorshavenoconﬂictofinteresttodeclare. Ethicalstatement

None.

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