Prediction of Difficult Laryngoscopy in Pregnant Women Undergoing Cesarean Section Using the Hyomental Distance in fully extended and neutral position of neck, in Comparison With four usual bedside tests: A prospective blinded study

Abstract

Background:�Unexpecteddifficultintubationthatmaybeconsideredtofailedintu- bationisamajorfactortoberelatedtomortalityandmorbidityfollowinggeneral� anesthesia. We aimed to elucidate the role of hyomental Distance in fully extended andneutralpositionofneckwithotherprevailingtestandtheirpossiblecorrelationin� predictingdifficultlaryngoscopyinparturientundergoingcesareansection. Materials and Methods: After institutional approval and obtaining inform consents, 716�consecutiveparturientASAphysicalstatusIandIIscheduledforelectivecesar- eansectionundergeneralanesthesia,�wereenrolledtothisstudy.�Eachpatientwas� evaluatedregardingHyomentaldistanceinextended�(HMDe)�andneutralposition� ofneck(HMDn),�NeckcircumferencetoThyromentalDistance(NC/TMD),�Ratioof� heighttoThyromentalDistance(RHTMD),�ModifiedMallampattiTest�(MMT)�and� UpperLipBiteTest(ULBT)��beforeinduction.�Laryngoscopicresultwasgradedac- cordingtoCormack-LehaneClassification.� Sensitivity,�specificity,� positivepredictive� valueandAUCorROCforeachairwaypredictorinisolationandincomparisonwith� eachotherwasestablished.� Results:�ThesensitivityofHMDeandHMDnwas�49.2�and�47.7%�respectively.��Sen- sitivityofMMTasanoldpredictivetestwas�79.3%�incomparisonwithsensitivity� ofNC/TMD,�RHTMDandULBT�(58.3%,�41.6%�and�50.7%�respectively).�Thedif- ferencesofAreaunderCurveinalltestsexceptULBTwerestatisticallysignificant� (P�<�0.05).� Conclusion:�InadditiontoMMT�(asanancientpredictor),�NC/TMDandHMDin� neutral position and fully extended of the neck; in parturient are good and reliable predictorsofdifficultlaryngoscopyandintubation.�