SonoSite S-Cath - Page 55

Chapter 4: Measurements and Calculations 45
Measurements
Tomakeacorrection,press Undoor
backtrackwiththetouchpad.
d PressSettocompletethetrace.
e Savethecalculation.
Forinformationontheautomatictracetool,see
“Totrace automatically(Doppler)”onpage 37.
To calculate Isovolumic Relaxation Time
(IVRT)
1 OnafrozenDopplerspectraltrace,press
Calcs.
2 Fromthecalculationsmenu,selectMVand
thenselectIVRT.
Averticalcaliperappears.
3 Usingthetouchpad,positionthecaliperatthe
aorticvalveclosure,and thenclick.
Asecondverticalcaliperappears.
4 Usingthetouchpad,positionthesecond
caliperatonset
ofmitralinflow.
5 Savethecalculation.(See“Tosavea
calculation”onpage 38.)
To calculate Delta Pressure: Delta Time
(dP:dT)
ToperformthedP:dTmeasurements,theCW 
Dopplerscalemustinclude velocitiesof300 cm/s
orgreateronthenegativesideofthebaseline.
(See“Spectraltracecontrols”onpage 23.)
1 OnafrozenCWDopplerspectraltrace,press
Calcs.
2 Fromthecalculationsmenu,selectMV, and
thenselectdP:dT.
A
horizontaldottedlinewithanactivecaliper
appearsat100cm/s.
3 Usingthetouchpad,positionthefirstcaliper
alongthewaveformat100cm/s,andthen
click.
Asecondhorizontaldotted linewithanactive
caliperappearsat300cm/s.
4 Usingthetouchpad,positionthesecond
caliperalongthewaveformat
300cm/s.
5 Savethecalculation.(See“Tosavea
calculation”onpage 38.)
To calculate Aortic Valve Area (AVA)
TheAVAcalculationrequiresameasurementin
2DandtwomeasurementsinDoppler.Afterthe
measurementsaresaved,theresultappearsin
thepatientreport.
1 MeasurefromLVOT(2D):
a Onafrozen2Dimage,press Calcs.
b Fromthecalculationsmenu,selectAo/LA,
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 MeasurefromLVOT,and thenmeasurefrom
AV(Doppler):
•ForVm ax, see“Tomeasurepeakvelocity”
onpage 43.Fromthecalculationsmenu,
selectAV,selectsamplesite,andthen
selectVmax.
•ForVTI,see“To
calculateVelocityTime
Integral(VTI)”onpage 43.Fromthe
calculationsmenu,selectAV,selectsample
site,andthenselectVTI.