SonoSite S-Cath - Page 57

Chapter 4: Measurements and Calculations 47
Measurements
4 Usingthetouchpad,positionthesecond
verticalcaliperatthepeakofthenext
heartbeat.
5 Savethecalculation.(See“Tosavea
calculation”onpage 38.)
To calculate Cardiac Output (CO) or Cardiac
Index (CI)
TheCOandCIcalculationsrequireStroke
Volumeand He artRatecalculations.CIalso
requiresBodySurfaceArea(BSA).Afterthe
measurementsaresaved,theresultappearsin
thepatientreport.
1 (CIOnly)FillintheHeightandWeightfields
onthepatientinformationform.TheBSAis
calculatedautomatically.(See
“Tocreatea
newpatientinformationform”onpage 27.)
2 CalculateSV.See“TocalculateStrokeVolume
(SV)orStrokeIndex(SI)”onpage 46.
3 CalculateHR.See“TocalculateH eartRate
(HR)”onpage 46.
To calculate Cardiac Output automatically
Thesystemcanmaintaintheaccuracyof
automaticCardiacOutputmeasurementsonlyif
theflowrateis1L/minorgreater.
1 MeasurefromLVOT(2D):
a Onafrozen2Dimage,press Calcs.
b Fromthecalculationsmenu,selectCO,and
thenselectLVOT D.
c Positionthecalipers.(See“Workingwith
calipers”on
page 33.)
d Savethecalculation.(See“Tosavea
calculation”onpage 38.)
2 Traceautomatically(Doppler):
Theautomatictracetoolalwaysmeasuresthe
peakregardlessoftheLiveTracesettingin
Presetssetup.
a DisplaytheDopplerspectraltrace
(waveform).
b ForSweep Speed,selectSlowor
Med.
c Press Trace,andthenpressAboveor

Belowforthepositionoftheautomatic
tracetoolrelativetothebaseline.
Theautomatictrace toolappearsinyellow.
Theresultsappearatthebottomofthe
screen.
d Freezetheimage.
Ifyouwanttochangethewaveform
measured,moveeachverticalcaliperby
clickingandthenusingthetouchpad.
PressSettoupdatetheresults.
Ifyouinvertthefrozenimage,turnthe
cineknob ,ormovethebaseline,
resultsarecleared.
e Savethecalculation.
WARNING:
To avoid incorrect calculation
results, make sure that the Doppler
signal does not alias.
To avoid an incorrect diagnosis:
• Do not use automatic Cardiac
Output calculations as the sole
diagnostic criteria. Use them only
in conjunction with other clinical
information and patient history.
• Do not use automatic Cardiac
Output calculations in neonatal
patients.
To avoid inaccurate velocity
measurements if you use PW
Doppler, make sure that Angle
Correction is set to zero.