GE CARESCAPE - Automatic agent identification with E-sCAiO, E-sCAiOV, E-CAiO, E; Basics of CO₂ measurement; Normal CO2 waveform; The origin of the CO2 waveform

Airwaygases
Anincreasedbalancegasvaluemayindicatetheamountofnitrogenushedoutfrom
thepatientintothecircuit.Theincreasemaybeduetoanaccumulationofnitrogen
duringlowowanesthesia.
Themonitorcalculatesend-tidalbalancegaswhenoxygenandCO
2
measurements
areactive.IfoxygenorCO
2
statusisinvalidoragentidenticationfails,themonitor
displaysthebalancegasvalueasinvalid.
AutomaticagentidenticationwithE-sCAiO,
E-sCAiOV,E-CAiO,E-CAiOVandE-CAiOVX
modules
TheE-moduleswithagentidenticationoptionwillautomaticallyidentifyandselect
Isourane,Desurane,Sevourane,EnuraneandHalothane.Themodulesareable
toidentifytwoagentssimultaneouslyanddisplayingthemasprimaryandsecondary
agents.Theinspiratoryandexpiratoryconcentrationsoftheagentaredisplayedin
anumericparameterwindow.Minimumconcentrationfortheidenticationis0.15
vol%.Theagentselectionremainsactiveeveniftheconcentrationdecreasesbelow
0.15vol%.Automaticagentidenticationisoperationalafterthenormalwarmupof
themodule(approximatelyveminutes).
●Ifrapidagentconcentrationchangesarerequired,freshgasowmustbe
increased.
●Anestheticagentconcentrationinthecircuitisaffectedbypatientuptake,
breathingsystemvolumeandthefreshgasow.Itquantiesthespeedofwash-in
andwash-outanestheticagents.
BasicsofCO₂measurement
NormalCO
2
waveform
TheCO
2
waveformisreferredtoascapnogramanditreectsthedifferentstagesin
breathing.Thecapnogramofahealthypatientundercontrolledventilationhasa
normalshape.ChangesintheCO
2
waveformmayindicatecompromisedpatient
respiratoryand/orcirculatoryfunctionorimpropermechanicalventilatorfunctionality.
TheoriginoftheCO
2
waveform
Thefollowingillustrationshowsanormalcapnogram.Inthisillustration,theletters
indicatethefollowing:
●A:Thegasrstexhaledisfromtheanatomicalandapparatusdead-space.It
containsnoCO
2
becauseithasnotbeeninthealveoliandnogasexchangehas
takenplace.
●B:Briey,theexhaledgasisamixtureofgasfromtheanatomicaldead-space
andgasfromthealveoli.
●C:Aplateauisreachedwhenthegasexhaledisentirelyfromthealveoli.The
end-tidalCO
2
(EtCO
2
)concentrationismeasuredattheendofthisplateau.
●D:Whenthenextinspirationstartsthecapnogramrapidlyfallstowardsthe
baseline.TheminimumlevelofCO
2
measuredduringtheinspiratoryphaseiscalled
theinspiredCO
2
concentration(normally0.0%).
2062971-001CARESCAPEModularMonitors301