Philips Expression MR400 - CO2 Low Flow and Occlusion Conditions

9‐4MonitoringAgentsandGases(AGENTOption) ExpressionMR400InstructionsforUse
Thebreathratelimitforaccuratelyresolvedend‐tidalgasvalues(atanI:Eratioof1:1)maybe
foundinAppendixA.TheeffectofotherI:Eratiosmaybecalculatedbydeterminingthelengthof
the
shortestinspiratory/expiratoryeventthatcanberesolvedaccurately:
t
resolved
=60/(2xBR
limit
(1:1)
BR
limit
(I:E)=60/((I+E)xt
resolved
)
Thedifferenceintheseresultswhencomparedtotherisetime'sspecificationisthatrise time's
onlytests10‐90%performance.Thisspecificationisfor(0+accuracy)to(100‐accuracy)%andis
thusmuchtougher.Theabilitytoproperlyresolveend‐tidalvaluescanbemeasuredbyusing
the
set‐updescribedinISO80601‐2‐55:2011figure201.101.Inshort,themethodconsistsof
samplinggasfromtwodifferentsourcesconnectedtoanelectricallycontrolledpneumaticvalve
topermitrapidswitchingbetweenthetwosources.Duringthetest,thevalveissettoswitchgas
sourceata
numberoffrequencies(simulatingtherangeofspecifiedbreathrates)andforeach
frequencytheend‐tidalvaluepresentedbythegasanalyzerisnoted.Fromadiagramofend‐tidal 
valueoverfrequency,thefrequencyatwhich thegasanalyzerisnolongerabletoresolveend‐
tidalvalues
accordingtospecificationisidentified.Thisabilitytoproperlyresolveend‐tidalvalues
islistedinthespecification.
CO2 Low Flow and Occlusion Conditions
CO2LowFlowwillbedisplayedandanalarmwillsoundintheeventofalowflowcondition
(wheneverthegasflowfallstoanamountthatis10percentlessthanthesampleflowratefor
theselectedpatienttype),asshowninthetablebelow.
Occlusionwillbe
displayedandanalarmwillsoundintheeventofanocclusioncondition
(wheneverthegasflowratehasfallenbelow40ml/minforatleast1second. Thetypicalcauseof
Fi error
Percent
Time
Et error
- - at gas sampling site
— as presented by gas analyzer
Patient Type Sample Flow Rate Flow Rate when Low Flow is Declared
Adult 200 ml/min ≤ 180 ml/min
Pediatric 200 ml/min ≤ 180 ml/min
Neonate 150 ml/min ≤ 135 ml/min