Chapter
8
Hemodynamic Measurements and Dynamics
of
the Assisted Circulation
8.1
Pressure,
Flow
and Dimension Measurements
8.
I.1
Invasive
Blood
Pressure Measurements
8.1.1.1
The Needle-Pressure Transducer System
The combination of a fluid-filled catheter and
a
pressure transducer
continues to be the most commonly used measurement system for in-
vivo recording of pulsatile blood pressure waveforms.
This blood
pressure measurement system can be applied to cardiac chambers, major
arteries and veins,
as
well
as
smaller
(-1
mm) vessels of the circulation.
This
is
because of
the
long,
well-established
and
improved
catheterization techniques in combination with angiographic imaging
modalities in clinical catheterization laboratories.
The catheter system
has the added advantage of the ease of injecting radio-opaque dyes for
visualization of the vasculature, as well as administering therapeutic
drugs.
Balloon catheter for angioplasty applications and micro-pore
catheter for local intravascular drug delivery have also become popular.
The
more recent multi-lumen, multi-functional catheters include
thermodilution, as well as the addition of electrodes for either atrial or
ventricular pacing capabilities. These technological advances have
promoted the popularity of interventional cardiology.
Forssmann and Cournand, who shared the
1956
Nobel prize in
Medicine with Richards, are the original inventors who decades earlier
first recorded blood pressure waveforms in peripheral arteries and
cardiac chambers. The catheter has the flexibility and maneuverability
