GE CARESCAPE - SvO2 measurement description; SvO2 troubleshooting

Mixedvenousoxygensaturation(SvO₂)
SvO
2
measurementdescription
TheSvO
2
valueismeasuredcontinuouslybyspectrophotometry.Thealgorithm
consistsofvedifferentparts:
●Initialization:Whenconnected,anumberofstart-upproceduresareperformed
priortonormaloperation.Theseproceduresincludetransferofcalibrationfactors
andinitializationofLEDcurrents.
●Calibration
●SignalprocessingandSvO
2
calculation:Lightofvariouswavelengths(red660nm
andinfrared810nm)istransmittedtothebloodthroughasingleplasticoptical
berintheoximetrycatheter,andreectedbackthroughaseparateopticalber
toaphotodetector.Thelightiselectricallytransmittedandanalyzed.Fromthe
amountofreectedlightitispossibletomeasuretheamountoflightabsorbed
byhemoglobinandoxyhemoglobin,resultingintheSvO
2
value.TheSvO
2
value
isdisplayedasapercentage.
●Automaticgaincontrol:Theintensityoftheredandinfraredsignalscanbe
ampliedbyfourdifferentgains.Thegainisselectedautomaticallytoachieve
optimalsignallevels.
●Signalquality
SvO
2
troubleshooting
ProblemSolution
SvO
2
levelsaretoohigh●Positionthecathetercorrectly.
●Calibrateinvivo.
Invivocalibrationfails●Checktheconnections.
●Checkthattheopticalcableshavenosharpbends.
●Iftheinvivocalibrationfailsagain,replacethecatheterand/orthe
opticalmodule,andrepeattheprocedure.
2062971-001CARESCAPEModularMonitors279