Abiomed Impella LD, User Manual

Page: 11 / 176

9 Impella LD
®
Circulatory Support System
PRESSURE SENSOR DRIFT AND
PLACEMENT SIGNAL NOT RELIABLE
SENSOR
MANUALLY ZEROING THE DIFFERENTIAL PRESSURE SENSOR
The electrical signal produced by the differential pressure sensor may drift
over time. This drifting is normal behavior and is characterized by an upward
or downward shift in the placement signal on the controller display. The
amplitude (peak-to-trough, or maximum to minimum) of the waveform will
not change. In addition, when sensor drifting occurs, the displayed flow rate
may not match the P-level.
If you observe that the placement waveform has shifted up or down on the
display, or the expected flow does not match the current P-level setting, zero
the differential pressure sensor by performing the following steps:
1.
Press the MENU key and select “Start Manual Zero.”
2.
Press OK to adjust flow level.
3.
The controller displays “Wait until the new flow level is reached” and
then “Offset calculation is in process.”
4.
Select OK to accept the new setting when the controller displays the
“Placement Signal Offset Adjust finished” message.
5.
The Impella ® will automatically be reset to the previous P-level.
ZEROING THE DIFFERENTIAL PRESSURE SENSOR WHEN THE
IMPELLA LD
®
CATHETER IS RUNNING
The controller software contains a data table listing the expected differential
pressure for a given motor current when the motor speed is set to a specific
value. To zero the differential pressure sensor while the Impella LD Catheter is
running, the software sets the motor speed and measures the motor current.
Using the data table, the software determines what the measured differential
pressure should be, then adjusts the signal from the differential pressure
sensor so that it matches the expected value.
PLACEMENT SIGNAL NOT RELIABLE AND EFFECTS ON FLOW
CALCULATIONS
If the pressure sensor fails, the controller can no longer calculate the flow
rate. The controller displays a “Placement Signal Not Reliable” alarm. The
placement screen displays a table with estimated flows and corresponding
MAPs in the bottom-left corner of the display. The Home screen displays
a yellow question mark over the heart icon and “Placement Monitoring
Suspended.” To silence this alarm, go to MENU and select SETTINGS/
SERVICE .
PLACEMENT SIGNAL NOT RELIABLE AND EFFECTS ON
POSITION CONTROL
If the pressure sensor fails, placement monitoring is switched off because
it is not possible to display the position of the catheter. In this case, the
motor current signal or imaging procedures can be used for position control.
As long as the motor current signal is pulsatile, the Impella LD Catheter is
correctly positioned across the valve. This signal must be monitored closely
because the catheter can become dislodged (displaced) when moving the
patient or changing the patient’s position. Therefore, if patient hemodynamics
change—for example, if arterial pressure falls or there are signs of left
ventricular failure—check the correct positioning of the catheter using
imaging procedures (eg, TEE) and the motor current signal.
SUCTION DETECTION DURING SENSOR DRIFT OR
PLACEMENT SIGNAL NOT RELIABLE
If sensor drift occurs or the pressure sensor fails, the controller can no longer
detect suction. The effectiveness of Impella LD Catheter support can only
be assessed by monitoring patient hemodynamics, cardiac imaging, and the
Impella LD Catheter motor current.
Signs of suction include:
• A drop in the patient’s arterial pressure
• Decreased output, if a cardiac monitor is in place
• Dampened or flat motor current waveforms
If imaging reveals that the suction is caused by the catheter inlet area in close
proximity to the intraventricular wall, reposition the catheter. If hemodynamic
parameters, such as low aortic pressure or high pulmonary artery pressure,
indicate suction caused by inadequate filling volume, reduce performance level.
OPERATING THE IMPELLA LD
®
CATHETER
WITHOUT HEPARIN IN THE PURGE
SOLUTION
The Impella LD Catheter is designed to be operated with a purge solution
that contains heparin. Operation of the system without heparin in the
purge solution has not been tested. In the event that a patient is intolerant
to heparin, due to heparin-induced thrombocytopenia (HIT) or bleeding,
physicians should use their clinical judgment to assess the risks versus
benefits of operating the Impella ® System without heparin.
If it is in the best interest of the patient to operate the system without
heparin, the dextrose solution is still required, and physicians should consider
systemic delivery of an alternative anticoagulant. DO NOT add any alternative
anticoagulant (such as a direct thrombin inhibitor) to the purge fluid. The
Impella LD Catheter has not been tested with any alternative anticoagulants
in the purge solution.
OPERATING THE IMPELLA LD CATHETER
IN ELECTROMAGNETIC FIELDS
The Impella LD Catheter contains a permanent magnet motor that emits an
electromagnetic field. This field may produce electromagnetic interference
with other equipment. In addition, other equipment that emits a strong
electromagnetic field may affect the operation of the Impella LD Catheter
motor.
ELECTROANATOMIC MAPPING (EAM) SYSTEMS
Examples of EAM Systems
• CARTO
®
3 System and
• CARTO
®
XP Navigation System (Biosense Webster, Inc.)
The electromagnetic field emitted by the Impella LD Catheter may produce
interference with the magnetic location detection component of the
electroanatomic mapping (EAM) system, particularly when the mapping
catheter is close to the Impella LD Catheter motor. For example, mapping
in the right or left ventricular outflow tracts places the mapping catheter in
close proximity to the Impella LD Catheter motor in the ascending aorta.
Electromagnetic interference may appear as:
• Instability in the displayed location of the mapping catheter
• Magnetic interference errors generated by the electroanatomic
mapping system
E
NG
LI
SH