Stroke volume variation derived from uncalibrated pressure waveform
analysis for the prediction of fluid responsiveness in cardiac surgical
patients with impaired left ventricular function

Adequate circulation of blood is dependent of cardiac function and preload: the
amount of blood present in the circulation. The better cardiac function and the
more blood present in the circulation, the better will be tissue oxygenation,
up to a specific maximum. Howver, lessa blood in the ciculation cause a
decrease in tissue oxygenation, and in mechanically ventilated patients in an
increased pulse pressure variation and stroke volume variation. Stroke volume
variation can be measured with a new, recently validated cardiac function
monitor using invasive arterial pulse pressure contour analysis. Variation in
blood pressure is measured as pulse pressure variation, whereas variation in
stroke volume is measured as stroke volume variation. The administraion of
intravenous fluids can cause an improved bloodcirculation. However, in patients
with a decreased left ventricular function, fluid administration may cause
decompensation.

The aim of the study is to investigate the accuracy of this new cardiac output
monitoring system in predicting fluid responsiveness.

This is a multicentre trial. Included are patients scheduled for cardiac
surgery with a decreased left ventricular function. 25 patiënts in the
UMC-Utrecht and 25 patiënts in the University Hospital in Aachen Germany.
Excluded are patients with tachyarrhythmias, central intracardiac shunting, and
children. Informed consent will be obtained during the pre-operative screening
in teh days before surgery.
Maximum observation will be 8 hours. The used catheters will stay in situ as
long as it is indicated, or will be removed if there is a contra-indication for
it (i.e. infection). Data will be obtained and saved anonymously. Data analysis
will be performed according to normal statistical procedures in the department
of peri-operative and emergency care.

According to a protocol for monitoring cardiac surgery patients with a severely
decreased left ventricular function, a pulmonary artery catheter will be placed
as a standard peri-operative monitoring technique. Thereby, it is usual to
administer an peripheral artery line in the radial artery. However, when we do
not succed in placing this radial artery line, the femoral artery in the groin
will be used. For this research, all patients will have an arterial line in a
femoral artery. There is no extra change for harm besides the normal wellknown
complications of administering intravascular catheters.