GE CARESCAPE - Oxygen measurement interpretation, CARESCAPE respiratory modules; Airway gases practicalities; Ventilation management

Airwaygases
Cardiogenicoscillationsappearwhen:
●AcontinuousfreshgasowisfedintothepatientY-piece.
●SidestreamgassamplingisdoneattheY-piece.
●Thepatientisventilatedwithalongexpirationtimeorlowrespirationtimes,and
whenthereisalongzeroowatend-expirationforsomeotherreason.
Oscillationscanbeeliminatedbyaddingaspacerwitha5mldeadspacebetween
theY-pieceandtheairwayadapter.Increaseddeadspacecreatesabuffervolume
betweentheY-pieceandthesamplingpoint,preventingtheinspiratoryandexpiratory
airfrommixingduringgassampling.MisinterpretationofEtCO
2
informationcanbe
avoidedthroughidentifyingcardiogenicoscillationandunderstandingthereasons
forit.
Oxygenmeasurementinterpretation,
CARESCAPErespiratorymodulesandcompact
airwaymodules
TheCARESCAPErespiratorymodulesandcompactairwaymodulesoxygen
measurementprovides:
●Inspiredoxygenlevel,theactualinspiredoxygenconcentration
●End-tidaloxygenlevel,theexpiredoxygenconcentration
●Inspiratory-expiratoryoxygendifferencereectspatient’sconsumedoxygen
volume-percentagefromtheadministeredgasmix
●Oxygram,adiagnostictoolbothinrealtimeandasatrend
Thepatientoxygenprovidesbreath-by-breathinformationaboutthebreathingcircuit,
alveolarventilationandsomevitalindicatorsofadequateoxygenation.
Oxygramisamirrorimageofacapnograminasteadystateinnormalpatient.Itisa
graphicpresentationofchangesinO
2
concentrationsintheairwaygas.Theoxygram
reectstheoxygenuptakefromthealveoli.Toavoidpatientadministeredhypoxicgas
mixestheinspiredfractionofoxygen(FiO
2
)shouldneverbelowerthat21%.
Airwaygasespracticalities
Ventilationmanagement
Normoventilation(adequatealveolarventilationofapatient)canbemaintained
bymonitoringtheend-tidalcarbondioxideandoxygenconcentrations,and
adequacyofventilationcanbemaintainedbymonitoringairwaypressures,volumes
andspirometryloops.Alveolarminuteventilationisusuallyadjustedtoachieve
normocapnia,whereEtCO
2
isintherangeof4.5%to5.5%(34mmHgto41mmHg).
Thisiscallednormoventilationasitisthenormalsituationinhealthypeople.
AlowEtCO
2
concentration(EtCO
2
<4%/30mmHg)indicateshyperventilation.
NOTE
AlowEtCO
2
valueinitselfisdependentfromtheventilation
volumevs.circulationstatus(lungperfusion).Thismeansthat
incaseoflowbloodpressure(e.g.shock)orshuntinglow
EtCO
2
valuesmaybeobservedwhileusinga“normal”TV/MV.
2062971-001CARESCAPEModularMonitors303