GE CARESCAPE - References used for MAC and MACage values; MAC values of different anesthetics in oxygen

Airwaygases
TheMACvaluescorrespondtothoseofhealthyadultsofabout40yearsold,and
cannotbeappliedtochildrenorelderlypatients.Ageandsomeotherindividual
factorsinuencingtheeffectofvolatileagentsarenottakenintoaccount.
Theothercalculationmethod,MACage,takesthepatient'sageintoaccount.Theage
rangeis0to150years.Thecalculationuses0ifageislessthan0,and100ifageis
morethan100.Inaddition,MACagecalculationsincludetheatmosphericpressure
andthepatient’s(highestmeasured)temperaturevalues.Ifnopatienttemperatureis
measured,37°Cisusedinstead.Forvolatileagentsthiscalculationmethodmeans
about6.7%decreaseofMACvaluewitheachincreasingdecadeoflife.MACageis
calculatedifitisenabledinthecareunitsettingsandthepatient’sageisgivenonthe
monitor.Ifnoageisgiven,MACiscalculateddespitethecareunitsetting.
ReferencesusedforMACandMACagevalues
Thealveolarconcentrationsoftraditional(MAC)andagedependent(MACage)values
arebasedonthefollowingreferences:
●ReferencesforanestheticagentMACvalues:
￭MaplesonW.W.:EffectofageonMACinhumans:ameta-analysis.Br.J.of
Anaesthesia1996;76:179-185
￭RampilI.J.;ZwassM.;LockhartS.;EgerE.I.II;JohnsonB.H.;YasudaN.;Weiskopf
R.B.:MACofI653insurgicalpatients,Anesthesiology.Tram-Rac71(3A):A269,
September1989
￭SchellerM.S.,PartridgeB.L.,SaidmanL.J.:MACofsevouraneinhumansand
theNewZealandwhiterabbit.Anesthesiology1987;67:A373
￭ISO21647:2004+C1:2005,Medicalelectricalequipment-Particular
requirementsforthebasicsafetyandessentialperformanceofrespiratory
gasmonitors.
●ReferencesforMACagecalculations:
￭Eger,E.I.II.:Age,minimumalveolaranestheticconcentration,andminimum
alveolaranestheticconcentration-awake.Anesth.Analg.2001;93:947-953
￭RampilI.J.;ZwassM.;LockhartS.;EgerE.I.II;JohnsonB.H.;YasudaN.;Weiskopf
R.B.:MACofI653insurgicalpatients,Anesthesiology.71(3A):A269,September
1989
MACvaluesofdifferentanestheticsinoxygen
Normalvalues(40-year-oldpatient)andcompensatedvalues(65-year-oldand
3-year-oldpatients):
1MAC
1MAC(65yrs)1MAC(3yrs)
Halothane
0.75%0.63%0.97%
Enurane
1.70%1.43%2.2%
Isourane
1.15%0.97%1.5%
Sevourane
2.05%1.73%2.65%
Desurane
6.00%5.05%7.80%
N
2
O100%82%
N/A
ThefollowingillustrationshowstheAgent%correspondingto1MACasfunctionofage:
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