Rev. Bras. Anestesiol. vol.67 número1

REVISTA

BRASILEIRA

DE

ANESTESIOLOGIA

www.sba.com.br

SCIENTIFIC

ARTICLE

Design

and

validation

of

an

oral

health

questionnaire

for

preoperative

anaesthetic

evaluation

夽

Gema

Ruíz-López

del

Prado

_,

_Vendula

_{Blaya-Nováková}

,

Zuleika

Saz-Parkinson

,

Óscar

Luis

Álvarez-Montero

,

Alba

Ayala

,

Maria

Fe

Mu˜

noz-Moreno

,

Maria

João

Forjaz

a_{HospitalClínicoUniversitario,DepartamentodeMedicinaPreventivaySaludPública,Valladolid,Spain}

b_{HospitalGeneralUniversitarioGregorioMara˜nón,ServiciodeMedicinaPreventivayGestióndeCalidad,Madrid,Spain} c_{InstitutodeSaludCarlosIII,AgenciadeEvaluacióndeTecnologíasSanitarias,Madrid,Spain}

d_{HospitalClínicoSanCarlos,InstitutodeInvestigaciónSanitaria,Madrid,Spain}

e_{HospitalUniversitarioInfantaLeonor,DepartamentodeOtorrinolaringología,Madrid,Spain} f_{HospitalUniversitarioPuertadeHierro,DepartamentodeOtorrinolaringología,Madrid,Spain} g_{InstitutodeSaludCarlosIII,EscuelaNacionaldeSanidad,Madrid,Spain}

h_{HospitalClínicoUniversitario,UnidaddeInvestigaciónBiomédica,Valladolid,Spain}

Received20May2015;accepted17August2015 Availableonline21March2016

KEYWORDS Patientsafety; Dentalinjury; Oralhealth; Oralhygiene; Questionnaire

Abstract

Backgroundandobjectives: Dentalinjuriesincurredduringendotrachealintubationaremore

frequentinpatientswithpreviousoralpathology.Thestudyobjectivesweretodevelopanoral

healthquestionnaireforpreanaesthesiaevaluation,easytoapplyforpersonnelwithoutspecial

dentaltraining;andestablishacut-offvaluefordetectingpersonswithpoororalhealth.

Methods:Validationstudyofaself-administeredquestionnaire,designed accordingtoa

lit-eraturereviewandanexpertgroup’srecommendations.Thequestionnairewas appliedtoa

sampleofpatientsevaluatedinapreanaesthesiaconsultation.Raschanalysisofthe

question-nairepsychometricpropertiesincludedviability,acceptability,contentvalidityandreliability

ofthescale.

Results:Thesampleincluded115individuals, 50.4%ofmen,with amedianageof58years

(range:38---71).Thefinalanalysisof11itemspresentedaPersonSeparationIndexof0.861and

goodadjustmentofdatatotheRaschmodel.Thescalewasunidimensionalanditsitemswere

notbiasedbysex,ageornationality.Theoralhealthlinearmeasurepresentedgoodconstruct

validity.Thecut-offvaluewassetat52points.

夽

ThisworkshallbeattributedtotheDepartmentofPreventiveMedicineandPublicHealth,ClinicUniversityHospital,Valladolid,Spain, andNationalSchoolofPublicHealth,InstituteofHealthCarlosIII,Madrid,Spain.Theclinicalpartofthestudywascarriedoutatthe DepartmentofAnesthesiologyandResuscitation,InfantaLeonorUniversityHospital,Madrid,Spain.

∗_{Correspondingauthor.}

E-mail:jforjaz@isciii.es(M.J.Forjaz). http://dx.doi.org/10.1016/j.bjane.2015.08.007

Conclusions: Thequestionnaireshowedsufficientpsychometricpropertiestobeconsidereda

reliabletool,validformeasuringthestateoforalhealthinpreoperativeanaesthetic

evalua-tions.

©2016SociedadeBrasileiradeAnestesiologia.Publishedby ElsevierEditoraLtda.Thisisan

openaccessarticleundertheCCBY-NC-NDlicense(

http://creativecommons.org/licenses/by-nc-nd/4.0/).

PALAVRAS-CHAVE Seguranc¸ado paciente; Lesãodentária; Saúdebucal; Higienebucal; Questionário

Projetoevalidac¸ãodeumquestionáriodesaúdeoralparaavaliac¸ãopré-anestésica nopré-operatório

Resumo

Justificativaeobjetivo: Aslesõesdentáriasqueocorremduranteaintubac¸ãotraquealsãomais

frequentesempacientescompatologiaoralprévia.Oobjetivodoestudofoidesenvolverum

questionáriodesaúdebucalparaavaliac¸ãonoperíodopré-anestesia,defácil aplicac¸ão por

pessoalsemformac¸ãoodontológica,eestabelecerum valorde corteparadetectarpessoas

commásaúdebucal.

Métodos: Estudodevalidac¸ãodeumquestionárioautoadministrado,projetadodeacordocom

umarevisãodaliteraturaerecomendac¸õesdeum grupodeespecialistas.Oquestionáriofoi

aplicadoaumaamostradepacientesavaliadosemumaconsultapré-anestesia.AanáliseRasch

daspropriedadespsicométricasdoquestionárioincluiuviabilidade,aceitabilidade,validadede

conteúdoeconfiabilidadedaescala.

Resultados: Aamostraincluiu115indivíduos,50,4%dehomens,comidademedianade58anos

(variac¸ão:38-71).Aanálisefinaldos11itensapresentouumíndicedeseparac¸ãodosindivíduos

de0,861eumbomajustedosdadosaomodelodeRasch.Aescalafoiunidimensionaleseus

itensnãoforaminfluenciadospelosexo,idadeounacionalidade.Amedidalineardasaúdebucal

apresentouboavalidadedeconstruto.Ovalordecortefoifixadoem52pontos.

Conclusões: Oquestionáriomostrou propriedades psicométricassuficientes para ser

consid-erado uma ferramentaconfiável,válida paramedir oestadodesaúdebucalnas avaliac¸ões

pré-anestesiaantesdaoperac¸ão.

©2016SociedadeBrasileiradeAnestesiologia.PublicadoporElsevierEditoraLtda.Este ´eum

artigo OpenAccess sobumalicenc¸aCCBY-NC-ND(

http://creativecommons.org/licenses/by-nc-nd/4.0/).

Introduction

Damage to teeth and oral tissues is one of the most frequent complications of endotracheal intubation and general anaesthesia in general.1,2 _{The incidence varies}

widely, with different studies reporting values between 1:4574 and 1:3 intubated patients.3---13 _{Previous dental}

pathology,6,8,10,11_{generalanaesthesia,}9,10_laryngoscopy3_and

difficult intubation4,6,8,11 _{have been commonly associated}

withdentalinjuryduringananaestheticprocedurein obser-vationalstudies.

Dentalinjuriesasacomplicationofgeneralanaesthesia areafrequentsubjectofreviewarticles,recommendations and guidelines issued by scientific societies.14---17 _Several

authors suggested specific charts for a systematic docu-mentation of the state of patients’ dentition before the interventionin ordertoavoid possiblelitigations,13,14,18---20

but little has been published about effective prevention strategies.

Perioperativedentalinjuriesseemtobemorerelatedto diseasesoftheoralstructuresthemselvesthantomedical errors during anaesthesia,11,21 _{dental injury risk}

minimi-zation should therefore start with a careful oral health evaluationduringthepreanaesthesiaconsultation.Because

correctassessmentoforal healthmaybedifficultfor per-sonnelwithout specialdentaltraining,6 _{andapplicationof}

commonly recommended and often extensive oral health surveysmaybetime-consuming,wehavedecidedtodesign asimple guidancetoolfor evaluatingthe oral healthin a preanaesthesiaclinic.

Theprincipalobjectiveofourstudywastodevelopa self-administeredquestionnaireoforalhealthandoralhygiene habitsforpatientsundergoinggeneralanaesthesiaand vali-dateitusingaRaschanalysis.Thesecondaryobjectiveofthe studywastoestablishacut-offvaluefordetectingpersons withpoororalhealth.

Methods

ThestudywasapprovedbytheInstitutionalReviewBoardin linewiththeprovisionsoftheDeclarationofHelsinki,and writteninformedconsentwasobtainedfromallsubjects.

Studypopulation

procedureingeneralanaesthesiainthishospitalare eval-uatedin this clinic. Minors, patients with legal guardians andpatientswithintellectuallimitationswhichmayimpede correctunderstandingofthequestionnairewereexcluded.

Questionnairedesign

A short, self-administered questionnaire was designed basedona review of literature identifiedthrougha Med-line search (using MeSH terms ‘‘oral health’’, ‘‘tooth loss/epidemiology’’and‘‘periodontaldiseases’’)and opin-ions of a panel of experts consisting of four members (maxillofacial surgeon, dentist, otorhinolaryngologist and anaesthesiologist) whohelped to adapt the questionnaire foritsuseinthepreanaesthesiaclinic.

Thequestionnaireoriginallyconsistedof23items identi-fiedthroughthebibliographicsearch.Theresponsescaleof theitemswasLikert-type,withresponseoptionsbasedon frequency.Eachresponsewasgivenascore,whichaddedup toamaximumof100pointsintotal.Theagewascategorized into8groups(18---25,26---35,36---45,46---55,56---65,66---75, 76---85, >85 years), assigning incremental values of 5---40 pointstoeachoneofthem.Thebodymassindex(BMI)was categorizedinto 3 groups (<25, 25---30, >30kg/m2_). Infor-mationabouthabitsconsidereddetrimentalfororalhealth (smoking, alcohol consumption), medication and other diseases(diabetes,osteoporosis,liverdisease,HIV,cancer or rheumatoid arthritis)wasalsoadded. The initial ques-tionnairewasanalysed independently by each oneof the expertsbasedontheirknowledgeandclinicalexperience.

Thepanelrecommendedexcludingthequestion‘‘howdo yourateyour oralhealth?’’asitwasconsidered tobetoo subjectiveand relatedmoretothequalityof lifeaspects (aesthetics and self-perception) rather than to true oral habits.Bisphosphonateswereaddedtothelistofharmful medicationsbecauseof itsassociationwithosteonecrosis. BMIdatareplacedthequestion‘‘areyouobese?’’asamore objectivemeasure.Theexpertsconsidered itnecessary to askabouttoothmobility,gumbleeding,toothacheand miss-ingteeth,astheseareunequivocalsignsofpoororalhealth. Thefinalversionofthequestionnaireincluded18items grouped into three dimensions. The general information groupconsistedoffiveitems;13itemswererelated exclu-sivelywithoralhealth:eightoftheseaddressedoralhealth and oral health habits and five items were dedicated to habitsandconcomitant diseaseswhich areknowntohave a negativeeffect on oral health. Higher scores indicated worseoralhealth.

The questionnaire wasfirst pilot-tested on10 patients andthenappliedtothestudypopulation.Thepatients com-pleted the questionnaire in the waiting room before the preanaesthesia assessment. The anaesthesiologist, previ-ouslytrainedinoralexplorationbyadentist,evaluatedthe stateoforalhealthandclassifieditasgood,fairorpoor.This oralexplorationincluded directobservation witha dental mirror,periodontalprobing,toothmobilityexaminationand calculationofthedecayed,missing,filledteeth(DMF)index. Aglobalratingoforalhealth(good,fair,poor)wasprovided bytheanaesthesiologistandthedentist,whoexaminedthe patientsindependentlyaftertheanaesthesiologist.

Statisticalanalysis

TheRaschmodelwasusedtotestthemeasurement proper-tiesoftheoralhealthquestionnaire.22_{TheRaschanalysisis}

themostcurrentvalidationscalemethodwhichfollowsan additiveprocessofjointmeasurementofpersonsanditems in the same dimension or construct.23 _{Information about}

Rasch analysis,explainedina friendlyway,maybefound elsewhere.23_{First,responsecategoriesofsomeoftheitems}

werecollapsedwherenecessaryinordertoensurethatthe categorythresholds(pointofequalprobabilityofresponse betweentwoneighbouringcategories)wereordered.Items with standardized residuals above ±2.5 were eliminated. A non-significant chi-squareof the item-trait interaction, withBonferronicorrection,indicatedagoodfittotheRasch model. The reliability was examined through the Person SeparationIndex(PSI)withthecriterionof≥0.7forgroup comparisonsand≥0.85forindividualcomparisons.23

Princi-palcomponentanalysisoftheresidualsandindependency

t-testwereusedtoensurethatallitemsofthescaleformed auniquedimension,withsignificantvaluesof<10%or the lowerconfidenceintervallimitofthebinomialof <0.05.24

Theitemsshouldbelocallyindependent,whichmeansthat correlationsbetweenstandardized residualsshouldnotbe high(criterionfixedat0.3).Theitemswerefreefrombias by sex, age (by median: ≤58, >58 years) and nationality (Spanish,other)ifthep-valueoftheBonferronicorrection associatedtotheanalysisofvariance(ANOVA)ofdifferential itemfunctioning(DIF)wasnotsignificant.Ifmorethanone itempresentedDIFforacertainfactor,atop-down purifi-cation analysiswasperformedandtheimpureitems(with a bias) were subject to a DIF analysis, because if differ-entitemsactinoppositedirections,theDIFgetscancelled out.25

Afterobtaininga fit totheRasch model,psychometric properties(normality,acceptabilityandconstructvalidity) ofthelinearscalewereexamined.TheKolmogorov---Smirnov test wasusedtoverifythenormal distributionofthe lin-earmeasure.Dataacceptabilitywasanalysedthroughthe differencesbetweenmeanandmedian(arbitrarystandard of ≤10% of the maximum score)26 _{and floor and ceiling}

effects(below15%).27_{Theknowngroupsvaliditywas}

exam-ined through the Student’s t-test and ANOVA in order to examinesignificant differencesinoralhealth bysex, age, obesity,nationalityandlevelofeducation.Criterion valid-ity was established by comparing the oral health linear measure with the results of dental examination (good, fair, poor), using ANOVA. The inter-observer concordance in the rating of oral health between the anaesthesiol-ogist and the dentist was assessed through the kappa index.

Finally,aReceiverOperatingCharacteristic(ROC)curve was calculated in order to identify a cut-off value for detecting poor oral health. The results of the oral cavity examination (poorvs.good/fairoral health)wereusedas the criterion variable.Sensitivity, specificity, positive and negativepredictivevalues(PPV,NPV)andpositiveand neg-ative likelihoodratios (LR+,LR−)were calculatedfor the selectedcut-offvalue.

The Rasch analysiswas performed withthe RUMM2030 program,28 _{andIBMSPSSStatisticsversion19.0(IBMCorp.,}

Results

Theadministeredversionofthequestionnaireincluded 18 items,5aboutgeneralinformationand13concerningoral health.Theestimatedtimeforcompletingthe18-item ques-tionnairerangedbetween1.5and2min.Theinter-observer concordance between the oral-cavity examination by the anaesthesiologist anddentistwasfoundtobesatisfactory after3daysoftraining(kappaindex=0.78;standarderror, SE=0.18).

Three ofthe118patients whowereapproachedin the preanaesthesiaclinicrefusedtoparticipateduetoimpaired visionandinabilitytowrite.Allquestionnairesanalysedhad 100% of the itemscompleted. Of the 115 patients,50.4% were men, witha mean age of 55.1 (standard deviation, SD=19.1;range:18---88)years.Ninety-threepatientswere Spanish (80.9%). The mean BMI was 26.8kg/m2_{; 24} per-sons were obese (BMI >30kg/m2_{; 20.9%). As for thelevel} ofeducation,68patientshadlessthansecondaryeducation (59.2%).Oralhealthwasconsideredasgoodin32patients (28.1%);fairandpoor oralhealth wasfound in37 (32.5%) and45patients(39.5%),respectively(Table1).

The first analysis of the 13 oral health items did not show good adjustment of data to the Rasch model. Two itemswere recoded:lastvisittothedentist (‘‘<6months ago’’and‘‘between6monthsand1yearago’’were com-bined) and gum bleeding frequency (‘‘very often’’ and ‘‘always’’ were combined). The items concerning drink-ing alcohol and smoking were eliminated because they measuredanotherconstruct(standardizedresiduals >2.5).

Table 1 Descriptive statistics of the patient sample (n=115).

Mean± SD;n(%)

Age 55.1± 19.1

Sex

Male 58(50.4)

Female 57(49.6)

BMI(kg/m2_{) 26.8±4.2}

BMIcategorized(kg/m2₎

<25 41(35.7)

25---30 51(44.3)

>30 23(20)

Nationality

Spanish 93(80.9)

Other 22(19.1)

Educationlevel

None 31(27.0)

Primarystudies 37(32.2)

Secondarystudies 27(23.5)

Universitystudies 20(17.4)

Oralhealth(basedonanoralexamination)

Good 32(28.1)

Fair 37(32.5)

Poor 45(39.5)

SD,standarddeviation;BMI,bodymassindex.

Location 3.0 2.0 TMOB. 3 TMOB. 2 TMOB. 1 RVD. 3 TBF. 2 PAIN. 1 LVD. 2 FMU. 3 FMU. 2 FMU. 1 TBF. 1 TMISS. 1 RVD. 1 GBF. 1 LVD. 1 TMISS. 3 DIS. 1 PAIN. 3

PAIN. 2 TBF. 3

RVD. 2 TMISS. 2 DIABE. 1 MEDIC. 1 GBF. 2 × × ××××××× ×××× × × × × × ×× × × × × × × × × × × ×× × × × × × × ×× × × × × × × × ×× × × × × × × × × ×× × × × × × × × ×× × × ×× ××× ××× × × × × = ×× ×× × × × × ×× × × × ×× ××××× × ××× × × × ×× × × ×× × 1.0 0.0 –1.0 –2.0 –3.0 –4.0 –5.0 person –6.0

Persons Items [uncentralised thresholds]

1

Figure1 Person-item thresholddistribution,inlogits(final

Raschmodel).

(DIABE,Diabetes;DIS,Diseases;FMU,Frequencyofmouthwash

use;GBF,Gumbleedingfrequency;MEDIC,Medication;LVD,Last

visittothedentist;PAIN,Painonchewing;RVD,Reasonfor

vis-itingthedentist;TBF,Toothbrushingfrequency;TMISS,Number

ofmissingteeth;TMOB,Toothmobility).

Analysis of the remaining 11 items presented good reli-ability (PSI=0.861) and good adjustment of data to the model(2(44)=64.168;p=0.025),withfitstatisticsof0.027

(SD=1.248)fortheitemsand−0.196(SD=0.914)for person-fit.Table2presentsthefinalversionofthequestionnaire, withascoring example.The fitstatisticsfor eachitemof thefinalmodelaresummarizedinTable3.

Theunidimensionality ofthescalewasconfirmed,with 7.83%significantt-testandanacceptableconfidence inter-valof thebinomial(95%confidenceinterval,CI95%=0.038; 0.118).The items ‘‘tooth brushingfrequency’’ and ‘‘pain onchewing’’ showedDIFby sexin opposite directions,so theDIFgotcancelledout(p=0.740).Theitem‘‘numberof missingteeth’’presentedDIFby age.NoitemshowedDIF bynationality.

Thethirdthresholdoftheitem‘‘toothmobilityinalmost allteeth’’represented the most severe oral health prob-lem, and the first threshold of the item ‘‘tooth brushing frequency≥3times/day’’representedtheleastsevereoral healthproblem(Fig.1).

Table2 Preanaesthesiaoralhealthevaluationquestionnairewithascoringexample.

Value 0 1 2 3

1.Howfrequently

doyouuse

mouthwash?

Morethan

oncea

day

Oncea

day

Sometimes Never

2.Howoftendoyou

brushyourteeth?

3ormore

timesa

day

1---2

timesa

day

Sometimes Never

3.Whenwasthe

lasttimeyou

wenttothe

dentist?

Lessthan

1year

ago

1year

ago

Morethan 2yearsago

4.Whatwasthe

reasonforyour

lastvisittothe dentist?

Check-up/cleaning

Fillings/root canal treat-ment

Tooth extrac-tion

Placementofacrown, bridgeorprosthesis

5.Howmanyteeth

doyouhave

missing?

None 1---2

teeth

Morethan 2teeth

Mostteeth

6.Doyou

experiencegum

bleeding?

Never Sometimes Very

often

7.Doyou

experiencepain

onchewing?

Never Sometimes Very

often

Always

8.Doyou

experiencetooth

mobility?

No Only1tooth 2---5 teeth

Almostallteeth

0 1

9.Areyoudiabetic? No Yes

10.Doyouhaveany

ofthefollowing

diseases?Cancer,

Osteoporosis,HIV,

Rheumatoid arthritis,Liver

disease(cirhosis)

No Yes

11.Doyoutakeany

ofthefollowing

medications? Corticoids, Phenytoin (antiepileptic), Bisphosphonates

(Fosamax,Boniva)

No Yes

Finalscorea _Column

sumscore A=5

Column sum-score B=6

Columnsumscore C=6

Raw score=A+ B+C=17

Linear mea-sure=66.861

a_{Calculationofthefinalscore:Step1,Sumupthescoreofitemsmarkedwiththevalue1(A=5);Step2,Sumupthescoreofitems}

markedwiththevalue2(B=6);Step3,Sumupthescoreofitemsmarkedwiththevalue3(C=6);Step4,Obtaintheinitialrawscore (A+B+C=17);Step5,Findthelinearmeasureassociatedwiththisrawscoreintheconversiontable(Table5).Inourexample,witha rawscoreof17,theassociatedlinearmeasureisof66.861ona0---100scale.

amean of 49.01(SD=17.85),mean---median differenceof 4.38%,and nofloor or ceilingeffects. Validity results are listedinTable5:oralhealthwassignificantlyworsein peo-ple over the age of 58 years and Spanish nationals, with

Table3 FitstatisticsfortheitemsofthefinalRaschmodel.

Item Difficulty SE Residuals 2(df=4) Probability

Frequencyofmouthwashuse −1.814 0.141 0.262 2.663 0.616

Toothbrushingfrequency −1.084 0.152 −1.478 6.170 0.187

Lastvisittothedentist −0.858 0.154 1.919 12.006 0.017

Reasonforvisitingthedentist −0.849 0.129 0.445 4.777 0.311

Numberofmissingteeth −0.495 0.132 −0.895 2.314 0.678

Gumbleedingfrequency 0.200 0.169 1.104 2.425 0.658

Diseases 0.551 0.236 −0.780 7.747 0.101

Painonchewing 0.840 0.141 1.339 5.732 0.220

Diabetes 0.999 0.252 −0.576 6.550 0.162

Toothmobility 1.098 0.145 −1.965 6.192 0.185

Medication 1.412 0.273 0.918 7.594 0.108

SE,standarderror;df,degreesoffreedom.

Table4 Conversiontablefromrawscorestothelinearmeasure.

Rawscore Linearmeasure(logits) Linearmeasure(0---100) Rawscore Linearmeasure(logits) Linearmeasure(0---100)

0 −5.250 0.000 13 0.015 57.908

1 −4.024 13.484 14 0.218 60.141

2 −3.190 22.657 15 0.420 62.363

3 −2.623 28.894 16 0.623 64.595

4 −2.198 33.568 17 0.829 66.861

5 −1.854 37.352 18 1.041 69.193

6 −1.559 40.596 19 1.264 71.645

7 −1.296 43.489 20 1.504 74.285

8 −1.054 46.150 21 1.771 77.222

9 −0.826 48.658 22 2.082 80.642

10 −0.607 51.067 23 2.474 84.954

11 −0.396 53.388 24 3.036 91.135

12 −0.189 55.664 25 3.842 100.000

health than the rest of the participants. The oral health linearmeasure increasedwithdentalexamination scores, followingasignificantlineartrend.

A ROCcurve wascalculated for thelinear scale, using thedentalexamination(poorvs.good/fairoral health)as variablecriterion,withanareaundercurve(AUC)of0.935 (SE=0.018,CI95%=0.92---0.99).Thecut-offvaluewassetat

52points(specificity=0.96;sensibility=0.86).ThePPV,NPV, LR+andLR−forthiscut-offvaluewere0.811,0.967,6.593 and0.052,respectively.

Discussion

The goal of the preanaesthesia evaluation is to detect patientswithanincreasedriskofcomplicationsanddesign effectivepreventionmeasures.The methodsusedfor pre-dictingpostoperativeproblemsfocusonthediseaseseverity, surgicalcomplexity,identificationofcomorbidities,and car-diacrisk,amongothers.Nevertheless,theconsequencesof oraldamagesecondarytoanaesthesiashouldnotbe under-estimatedasoral healthisimportantforagoodqualityof

life29,30 _{andfor goodhealth ingeneral.Ourobjectivewas}

todesign ascreening toolfor assessingthe oral healthof patientsundergoingpreanaesthesiaevaluation.

Thequestionnaireisshort,easytounderstand, accept-abletopatientsandfeasibletoapplyintheclinicasitonly takesabout 2min tocomplete. The timing of the admin-istration --- after examination by the nurse while waiting tobeseenbytheanaesthesiologist---favourstheresponse andcompletionrateand increasespatients’awareness of thiscomplication.Theresponseoptionsaresimilar,butnot exactlythesameforeachquestion,whichpreventsthe cen-traltendencybias.Thecontentvaliditywassupportedbya panelofexperts.

The questionnaire is reliable,allowing for comparisons betweenindividuals.23 _{Furtherstudies thatadministerthe}

questionnairein differentoccasions areneeded to evalu-atethetest---retestreliability.Theunidimensionalityofthe scale,representingasingleconstruct,permitsthescoreof alltheitemstobeaddedasalinearmeasure.Alinear mea-sureisimportantforinterventionstudiesandclinicaltrials asitallowsapplyingparametricstatisticaltests.

Almost all items were free from bias by sex and age. However,olderpatientsscoredhigherintheitem‘‘number of missing teeth’’, a fact previously documented.29 _The

questionnairedisplayedadequatediscriminantvalidityand allowedastatisticaldifferentiationaccordingtowell-known oralhealthriskfactors:educationlevel31---33_andBMI.34,35_The

Table5 Descriptiveanalysisofdataandparametrictests(Student’st-testandANOVA)for thelinearmeasureofpoororal

healthaccordingtodifferentsociodemographicvariables.

Variable Frequency(n) Mean SD p

Age(years) <0.001

≤58 58 38.7 16.7

>58 57 59.5 11.9

Sex 0.209

Male 58 51.1 13.2

Female 57 46.9 21.5

Nationality 0.017a

Spanish 93 50.9 17.7

Other 22 40.9 16.5

Educationlevel <0.001

None 31 63.4 11.1

Primarystudies 37 53.1 9.7

Secondarystudies 27 45.4 10.6

Universitystudies 20 24.0 18.4

BMI(kg/m2_{) <0.001}

<25 41 40.0 22.0

25---30 51 51.2 12.9

>30 23 60.2 9.8

Oralhealth <0.001

Good 32 30.7 17.1

Fair 37 45.8 11.4

Poor 45 64.1 7.6

SD,standarddeviation;BMI,bodymassindex.

a_{Non-significantwhenadjustedbyage.}

comparedtothedentalexamination,butfurtherstudiesare neededtoexaminethepredictivevalidityofthe question-nairebycomparingthescoresobtainedwiththeintubation outcome.Onestudyreportedthat80%oftheinjurieswere classifiedas ‘‘unavoidable’’, which raises the question of theusefulnessofpredictingthisevent.Severalauthorshave foundthatitisdifficulttopredictdentaldamage,however, theyhavelookedatpredictingadifficultintubation8,13,19,36

ratherthantheriskofdentalinjuryitself.

Dentalinjuryhasnotbeendemonstratedtobemore fre-quentinemergencysurgeries8,10,12,13,19,36_{ortobeassociated}

withthelevelofexperienceoftheanaesthesiologist.7,12,19

Severalmajorstudies have emphasizedthat dentalinjury wasup to50 times morelikely tooccur in patients with previousdentalpathologies,8,10_{whichsuggeststhatthe}

per-sonalpredispositionis moreimportantthantheactionsof theanaesthesiologist.Thedesignofthequestionnairewas basedonthispremise.At thesametime,itisthebiggest limitationofourstudy:thereisnoevidenceuptodatethat beingaware of theoral health conditionsof the patients decreasestheriskofdentalinjuryduringananaesthetic pro-cedure. Acohort study of patients evaluatedthroughour questionnaireandfollowed-upfor theincidenceof dental injuryaftertheanaestheticprocedurewouldbenecessary toestimate itsutility in reducing dentaldamage. Still, a carefulexaminationoftheoralcavityisconsideredan inte-gralpartofthepreanaesthesiaevaluation.Onestudynoted that while pre-existing dental pathology was present in

two-thirds ofthecases, itwasnoticed bythe anaesthesi-ologistinonlyone-fifthofthepatientspriortointubation.6

Therefore, our questionnaire for detecting patients with poororalhealthmayserveasaguidancetothe anaesthe-siologist assessingthe risk of dentalinjury.In addition,it offersacut-offvaluefordetectingpoororalhealth.

Otherlimitationsofourstudyincludearelativelysmall samplesize37_{andthefactthatthedatawerecollectedfrom}

asinglecentre.Despite thesmallnumberof participants, wehaveachievedagoodfittotheRaschmodel.

Itisnotclearwhichpreventivemeasures totake when apatientisconsideredatanincreasedriskofdentalinjury. The useofprotectivedevicessuchasmouthguardsis con-troversial:whilesomeauthorsarguethattheydecreasethe alreadylimited amount ofspace available,6,12 _others

con-cluded that the differencein timeneeded for intubating apatientwithor withouta mouthguardwasnotclinically relevant.38 _{Custom-made mouthguards may be less bulky}

thanothermethodssuchasusinganimpressionputty,20_but

theyaremore costly andrequire timetomanufacture.If theriskofdentalinjuryisconsideredtobehigh,previous dentalassessmentisrecommended.Alternativeanaesthesia andintubationtechniquesmayalsobeconsideredwhenever possibleinsuchcases.Onegroupproposedaspecial tech-niqueforprotectingverylooseteeth,39_{butpreservationof}

Summary

Ourgoalwastodevelopandvalidateaquestionnaireoforal healthandoralhabitssuitableforapreanaesthesiaclinic. Thisquestionnairehasdemonstratedsufficient psychomet-ric properties to be considered a reliable and valid tool formeasuringthestateoforalhealth, andalsotakesinto accountsociodemographicfactors knowntobeassociated withoralhealthandgeneralhealthstateofthepatient.

Someofthebenefitsofourquestionnairemaybe classi-fyingpatientsaccording tothedentalinjuryrisk, alerting the anaesthesiologist about complicated patients where additional precautions would be necessary during intuba-tion, informing patients with higher scores about their increasedrisk,raisingpatients’awarenessaboutthe impor-tance of good oral health, suggesting dental treatment beforesurgeryinordertopreventaninjury,anddecreasing thecompensationclaimswhichwouldresultinsavings.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

Acknowledgments

The authors would like to thank Dr. Juan Carlos Llodrá-Calvo, DMD,PhD, professorof Preventive and Community DentistryattheUniversityofGranada,Granada,Spain,Dr. FernandoNájera-Sotorrio,MD,maxillofacialsurgeonatthe Quirón Hospital, Madrid,Spain, and Dr.José María Calvo-Vecino,MD,PhD,HeadoftheDepartmentofAnaesthesiology attheInfantaLeonorUniversityHospital,Madrid,Spain,who servedasscientificadvisorsonthepanelofexperts,fortheir collaborationinthisstudy.

Nofundingwasreceived.

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