|The CardioQ uses an interactive monitor. The screen displays the waveform which confirms optimal probe position. There is a continuous display of the patient's haemodynamic parameters.
The CardioQ's default display parameters are
CO (cardiac output)
SV (stroke volume)
FTc (corrected f low time)
PV (peak velocity)
MD (minute distance)
HR (heart rate)
CardioQ waveform and measured variables
With the exception of systemic vascular resistance, any six of the above parameters can be displayed at once and all are automatically trended. A navigator control knob is rotated to browse the menu and pushed to select. This includes the input of patient biometric data into the fixed stored nomogram that is used to estimate aortic cross sectional area. Speakers are included in the unit which gives an audible display of the doppler frequency shift spectrum produced by red blood cells moving in the path of the ultrasound beam. Listening to the audible signal aids optimization of the waveform.
All newer generations of doppler equipment contain sound frequency or velocity spectrum analyzers for hard copy recording. They display a spectrum of the various velocities present at anytime and are, therefore, called spectral velocity recordings. This results in the typical waveform seen on the monitor of blood flow velocity in the descending thoracic aorta. The display is accomplished by microcomputers that are able to de-code the returning complex doppler signal and process it into its various velocity components. There are two basic methods for accomplishing this. The most popular is Fast Fourier Transform and the other is called Chirp-Z Transform.
How to use the CardioQ monitor (streaming video)