GE CARESCAPE - Sidestream gas sampling; Minimum Alveolar Concentration (MAC); MAC and MACage

Airwaygases
Volume
sampledduring
expiration
10ml5ml3.33ml2.5ml
Totalvolume
sampled
15ml7.5ml5ml3.75ml
Sidestreamgassampling
TheE-modulesuseasidestreamgassamplingmethod.Itmeansthatasampleof
patient’srespiredgasesfromthesamplingsiteistransportedthroughasampling
linetothemoduleforanalysis.
Asidestreamgasanalyzertakesaconstantsamplefromthepatientairwayadapter
atthefollowingsamplerates:
●CARESCAPErespiratorymodules:120ml/min
●Compactairwaymodules:200ml/min
●E-miniC:150ml/min
Totalsamplesizevolumeduringonerespiratorycycledependsontherespirationrate.
MinimumAlveolarConcentration(MAC)
NOTE
CARESCAPErespiratorymodulesandcompactairway
modulesonly.
TheuseofeithertraditionalMACorMACageisselectedduringmonitorconguration.
TheMACageprovidesageandtemperaturecompensatedmeasurement.Toenable
MACagecalculations,enterpatient’sagetothemonitorandattachatemperature
sensor.Ifthepatient’sageisnotgiven,themonitorshowsnormalMACevenif
MACagehasbeenselected.
NOTE
TheMACvaluedisplayedbythemonitoristhatofexhaled
air,anditdoesnotalwayscorrespondtotheamountof
anestheticinthepatient’sorgans.
CAUTION
Patient-specicMACisaffectedbyseveralfactorssuchas
patientageandbodytemperature.
MACandMACage
Theminimumalveolarconcentration(MAC)conceptisbasedontheassumptionthat
inasteadystate,thealveolarpartialpressureofagasisequaltothepartialpressure
intheeffectororganofthecentralnervoussystem.MACvaluesareusedtoestimate
thelevelofanesthesiacausedbyvolatileanesthetics.
TheMACvaluecanbedisplayedinanumericparameterwindow:1MACisthealveolar
concentration(end-tidal)oftheagentatwhich50%ofpatientsdonotrespondto
anoxiousorsurgicalstimulus.Thevalueiscalculatedfromtheactualmeasured
anestheticagentandN
2
Ovalueswithempiricalformulasbasedonstatisticalstudies
withanesthetizedpatients.
ThemonitorcandisplaytwodifferentMACvalues,MACorMACage,basedondifferent
formulas.TheuseofMACorMACageisselectedduringinstallationandconguration.
298CARESCAPEModularMonitors2062971-001