GE CARESCAPE - Dips in capnogram

Airwaygases
●E:Withascale,theheightofthecapnogramtellsyoutheend-tidalCO
2
concentration.ThemonitorautomaticallycalculatesanddisplaytheEtCO
2
in
numbers.EtCO
2
approximatesthealveolarCO
2
concentrationbecauseitis
measuredwhenthepatientexhalesvirtuallypurealveolargas.
●1aand1d=inhalation
●1band1c=exhalation
EtCO
2
value%EtCO
2
valuemmHgIndicates
4.5%to5.5%34mmHgto41mmHg
normocapnia
<4%<30mmHg
hypocapnia
>6%
>45mmHg
hypercapnia
Dipsincapnogram
Thedipsseeninthecapnogramduringexpirationarerelatedtothesidestreamgas
sampling,thecontinuousgasowtotheY-piece,andpatient’scardiaccontractions,
whichcauseintra-thoracicpressurechangesandthereforeowvariations.
ThealterationsinexpiredCO
2
waveformarecardiogenicmovementsofexhaledand
circuitgasatthesidestreamgassamplingsite.Whentherespiratorygasowdrops
belowthegassamplingrate,avariablemixtureofCO
2
freefreshgasandexhaledCO
2
richgasissampled.ThiscausesvariationsinsampledCO
2
concentrations.
Intheillustrationbelow,CO
2
waveformistheoneontop,andowisthelower
waveform.
1.Expiration
2.Cardiogenicoscillations
302CARESCAPEModularMonitors2062971-001