RevBrasAnestesiol.2014;64(6):391---394
REVISTA
BRASILEIRA
DE
ANESTESIOLOGIA
OfficialPublicationoftheBrazilianSocietyofAnesthesiologywww.sba.com.br
SCIENTIFIC
ARTICLE
Comparison
of
different
tests
to
determine
difficult
intubation
in
pediatric
patients
Mehmet
Turan
Inal
∗,
Dilek
Memis
¸,
Sevtap
Hekimoglu
Sahin,
Isıl
Gunday
DepartmentofAnesthesiologyandReanimation,TrakyaUniversityFacultyofMedicine,Edirne,Turkey
Received4November2013;accepted5February2014 Availableonline11March2014
KEYWORDS Difficultintubation; Pediatrics;
Predictivetests
Abstract
Background: The difficulties with airway management is the main reason for pediatric anesthesia-relatedmorbidityandmortality.
Objective: Toassess thevalue ofmodified Mallampatitest, Upper-Lip-Bite test, thyromen-taldistanceandtheratioofheighttothyromentaldistancetopredictdifficultintubationin pediatricpatients.
Design:Prospectiveanalysis.
Measurementsandresults:Datawerecollectedfrom5to11yearsold250pediatricpatients requiring tracheal intubation. The Cormack and Lehaneclassification was used toevaluate difficultlaryngoscopy.Sensitivity,specificity,positivepredictivevalueandAUCvaluesforeach testweremeasured.
Results:ThesensitivityandspecificityofmodifiedMallampatitestwere76.92%and95.54%, whilethoseforULBTwere69.23%and97.32%.Theoptimalcutoffpointfortheratioofheightto thyromentaldistanceandthyromentaldistanceforpredictingdifficultlaryngoscopywas23.5 (sensitivity, 57.69%;specificity,86.61%)and 5.5cm(sensitivity, 61.54%;specificity,99.11%). ThemodifiedMallampatiwasthemostsensitiveofthetests.Theratioofheighttothyromental distancewastheleastsensitivetest.
Conclusion: TheseresultssuggestedthatthemodifiedMallampatiandUpper-Lip-Bitetestsmay beusefulinpediatricpatientsforpredictingdifficultintubation.
© 2014SociedadeBrasileirade Anestesiologia.Publishedby ElsevierEditoraLtda.Allrights reserved.
PALAVRAS-CHAVE Intubac¸ãodifícil; Pediatria; Testespreditivos
Comparac¸ãodediferentestestesparadeterminarintubac¸ãodifícilempacientes pediátricos
Resumo
Justificativa: Asdificuldadesnomanejodasviasaéreassãoaprincipalcausademorbidadee mortalidaderelacionadaàanestesiapediátrica.
∗Correspondingauthor.
E-mails:[email protected],[email protected](M.T.Inal).
0104-0014/$–seefrontmatter©2014SociedadeBrasileiradeAnestesiologia.PublishedbyElsevierEditoraLtda.Allrightsreserved.
392 M.T.Inaletal.
Objetivo:AvaliarovalordotestemodificadodeMallampati,testedamordidadolábiosuperior, distânciatireomentoniana erelac¸ãoaltura-distânciatireomentonianapara preverintubac¸ão difícilempacientespediátricos.
Projeto: Análiseprospectiva.
Mensurac¸õeseresultados:Dadoscoletadosde250pacientespediátricos,comidadesentre5 e11anos, submetidosàintubac¸ãotraqueal.Aclassificac¸ãodeCormackeLehanefoi usada paraavaliarlaringoscopiadifícil.Osvaloresdesensibilidade,especificidade,preditivopositivo eAUCparacadatesteforamregistrados.
Resultados: AsensibilidadeeespecificidadedotestemodificadodeMallampatiforam76,92% e95,54%,enquantoparaoULBTforam69,23%e97,32%.Opontodecorteidealparaarelac¸ão altura-distânciatireomentonianaedistânciatireomentonianaparapreverlaringoscopiadifícil foi23,5(sensibilidade,57,69%;especificidade,86,61%)e5,5cm(sensibilidade,61,54%; especi-ficidade,99,11%).OtestedeMallampatimodificadofoiomaissensíveldostestes.Arelac¸ão entrealtura-distânciatireomentonianafoiotestemenossensível.
Conclusão:EssesresultadossugeremqueostestesdeMallampatimodificadoedamordidado lábiosuperiorpodemserúteisempacientespediátricosparaaprevisãodeintubac¸ãodifícil. ©2014SociedadeBrasileiradeAnestesiologia.PublicadoporElsevierEditoraLtda.Todosos direitosreservados.
Introduction
Difficultieswith airwaymanagement in pediatric patients
are a major reason for cardiac arrest, brain injury and
death.1---4Thuspreoperativeevaluationofthedifficult
intu-bationisimportant.
Differentpredictivetestsfordifficultlaryngoscopywere usedinadultpatients,5---11buttherewascontroversyabout
theusageofthesetestsinpediatricpatients.
The modified Mallampati test(MMT) isa simpleairway assessmentmethodandiswidelyused.5Theupperlipbite
test(ULBT)foundbyKhanetal.6isanotherpredictivetest.
The measurement of thyromentaldistance (TMD) remains widelyused.7TheratioofheighttoTMD(RHTMD)8isanother
methodfordifficultairwayprediction.
Thegoalofthisstudywastoassessthevalueof differ-entpredictive tests for difficult laryngoscopyin pediatric patients.
Materials
and
methods
After obtaining Ethics Committee approval for the study, writteninformedconsentwasobtainedfromtheparentsof eachchild.Patientsaged5---11yearsrequiringendotracheal intubationweretakenintothestudy.Patientswith limita-tionofcervicalmovementorunabletoopenthemouthwere notincludedinthestudy.
Preoperatively, the MMT, ULBT, TMD and RHTMD mea-surementswere recorded by an anesthesiologist who was unawareaboutthestudy.
TheMMTwasclassifiedasfollows:ClassI---softpalate, fauces,uvula,andpillarscanbeseen;ClassII---softpalate, fauces,anduvulavisualized;ClassIII---softpalateandbase ofuvulacanbeseen;andClassIV---softpalatenotseen.5
ClassIIIandIVareacceptedasdifficultintubationsigns. The ULBT was performed using the following criteria: Class I --- lower incisors can bite the upper lip above the vermilionline, ClassII---lowerincisorscanbitetheupper
lip belowthe vermilionline, andClass III--- lowerincisors cannot bite theupper lip. ClassesI and II wereaccepted aseasy intubation,and Class III wasaccepted asdifficult intubation.6,7,9
TheTMD,describedasthedistancebetweenthe laryn-gealprominenceofthethyroidandthementalprotuberance ofthemandibula,wasrecorded.TheRHTMDwasthen cal-culated.
Standard monitoring wasused for each patient. Intra-venous thiopental(3mg/kg), fentanylcitrate(1/kg)and
atracurium (0.5mg/kg) were used. Anesthesia was main-tainedwith2.0%sevofluraneand1:1O2/N2Oat2Lmin−1.
Anesthesiologists,blindedtothestudy,evaluatedthe air-waybyusingtheCormack---Lehaneclassification.12GradesI
(glottisfullyexposed)andII(glottispartiallyexposedwith anteriorcommissurenotseen)wereacceptedaseasy intu-bations.GradesIII (onlyepiglottisseen) andIV(epiglottis notseen)wereacceptedasdifficultintubations.
Statisticalanalysis
Resultsareexpressedasmean±standarddeviationor num-ber.Areaunderthecurve(AUC)ofthe receiveroperating characteristic (ROC)curve wascalculated.Cut-offpoints, sensitivity,specificity,andpositiveandnegativepredictive values were calculated. AUCs were compared by using z
statistics. A p value <0.05 was considered as statistically significant.
Results
Atotalof250patientsweretakenintothestudy.Ofthese, 131 (52.4%)weremaleand119 (47.6%)werefemale.The meanageofthepatientswas9.34±1.59years,themean weight was 33.40±6.76kg and the mean height of the patientswas134.42±7.11cm(Table1).
Differenttestsanddifficultintubationinpediatrics 393
Table1 Demographicdata.
Gender(M/F) 131/119
Age(year) 9.34±1.59
Weight(kg) 33.4±6.76
Height(cm) 134.42±7.11
Table2 Distributionoflaryngoscopicview. Mallampaticlass(n)
1 133
2 87
3 29
4 1
Cormack-Gradeview(n)
1 153
2 71
3 18
4 8
RHTMD 22.12±1.39
TMD(cm) 6.10±0.28
and24patientshadclassIIIULBT(Table1).In26patients (10.4%)wedetectedCormackandLehaneGrade3or4 air-way(Table2).
Table3showscut-offpoints,sensitivity,specificity, posi-tiveandnegativepredictivevaluesandAUCSforMallampati, ULBT,TMDandRHTMDparameters.Thesensitivityand speci-ficityofMallampatitestandULBTwere76.92%,95.54%and 69.23%,97.32%,respectively.
TheoptimalcutoffpointfortheRHTMDandTMDwas23.5 (sensitivity,57.69%;specificity,86.61%)and5.5cm (sensitiv-ity,61.54%;specificity,99.11%).
AUCs were0.894forMallampati, 0.914for ULBT,0.794 forTMDand0.748forRHTMD.Therewassignificant differ-encebetweenAUCsofMallampati/RHTMDandULBT/RHTMD (p<0.05).
Discussion
Ouraimwastounderstandthevalueofdifferenttestsfor difficult laryngoscopy in pediatric patients. These results suggest that there were significant differences between AUCs of MMT vs. RHTMD and ULBT vs. RHTMD tests. The
MMTtest was themost sensitive andthe RHTMD wasthe leastsensitive.TheTMDhadthehighestspecificity,positive predictivevalue,andaccuracy.
Theincidenceofdifficultairwaymanagementinchildren israre.Eseneretal.13reportedairwaydifficultiesof1.3%in
theirstudy,andanotherstudybyGencorellietal.14reported
airwaydifficultiesof1.7%.
The predictive values of ULBT, MMT,TMD, and RHTMD tests have been reported in the adult patients.6---11 Khan
etal.6 designedaprospective studytocomparetheULBT
and MMT for difficult intubation. They reported that the ULBT showed significantly higher specificity and accuracy than the MMT.They alsoreported that there was no sig-nificantdifferencebetweensensitivity, positivepredictive value,andnegativepredictivevalueofthetests.They con-cludedthattheULBTisanacceptableoptionforpredicting difficult intubation. Anotherstudy made by Salimi et al.7
compared the ULBT with the TMD. The authors reported higherspecificity andpositive predictive value withULBT thantheTMD.Theyconcludedthatthesensitivitiesofthe ULBT and TMD were not significantly different. Krobbua-banetal.8found that theRHTMDhad ahighersensitivity
andpositivepredictive value.The authorsconcludedthat theRHTMD maybeausefultest fordifficultlaryngoscopy. Another study9 compared the ULBT and MMT scores and
foundthatbothtestsarepoorpredictors.Theauthors con-cluded that this result was mainly caused by the large proportionoffalse-negativeratingsintheirtrial.Asimilar studybyHesteretal.10foundthatthesensitivity,specificity,
andpositivepredictivevalueoftheULBTtestwerehigher thanthoseoftheMMT.Honarmandetal.11 concludedthat
theRHTMD may bea useful screening test for predicting difficultlaryngoscopyinobstetricpatients.
Tothisdatethereislittledataabouttheusageofthese predictive tests in pediatric patients. Baudouin et al.15
designed a study to assess the value of MMT and TMD in 347 pediatric patients. The authors found that the usage ofMMTwasimpossibleinpatientsbelow18monthsofage anddifficultbelow5years.Theauthorsalsoreportedthat ahighMMThadpoorconnectionwithCormackandLehane grade.TheyalsoreportedthattheMMTisnotagoodtest topredictdifficultintubationinchildren.TheTMDseemed morereliable. Inadultstheminimal TMDis6cm,whilein infantsand childrenit is smaller.16 It is reportedthatthe
TMDis 4.1---5.8cm in Chinesechildren aged4---12 years.17
WefoundtheoptimalcutoffpointfortheTMDfor predict-ing difficult laryngoscopy tobe 5.5cm. Aggarwal et al.18
madeastudy tofindthepredictors ofdifficult intubation
Table3 Cut-offpoints,sensitivity,specificity,positive,andnegativepredictiveandAUCvalues. True
positive
False positive
True negative
False negative
Accuracy Sensitivity Specificity +PV −PV AUC
RHTMD 19(7.6) 87(34.8) 137(54.8) 7(2.8) 62.4 57.69 86.61 48.6 90.3 0.748a,b
TMD 16(6.4) 2(0.8) 222(88.8) 10(4.0) 95.2 61.54 99.11 93.8 92.1 0.794 Mallampati 20(8.0) 10(4.0) 214(85.6) 6(2.4) 93.6 76.92 95.54 66.7 97.3 0.894b
ULBT 18(7.2) 6(2.4) 218(87.2) 8(3.2) 94.4 69.23 97.32 75.0 96.5 0.914a
PV,positivepredictivevalue.
394 M.T.Inaletal.
in 1---5 years oldpediatric patients. The authors assessed theusefulnessofinterincisorgap,MMT,TMD,sternomental distance,neckcircumferenceandRHTMD.Theauthors con-cludedthattheTMDwasthemostvaluabletestinpredicting difficultintubation.
The possiblelimitationofthisstudy isthatchildren do notcompletelyunderstandtheinstructions.
In conclusion, the MMT and ULBT tests are useful and theirAUCvalueswerehigherthanthoseofothertests;thus they can be used for predicting difficult laryngoscopy in pediatricpatients.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
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