16
Guidelines to Prevent Air Entrainment during Support
Guidelines to prevent air entrainment during support include the following:
Monitor the volume with TEE and pressures.
Reduce CentriMag flow rate while the chest is open.
Reduce RPM for any indication of inadequate volume, during manipulation of the heart, or prior to moving the patient.
Monitor the tubing for chatter and be prepared to respond by decreasing RPMs and giving volume.
As soon as practical, set the low-flow alarm at 75% of the target flow.
Train staff that air can be drawn into the vasculature by the flow characteristics of circulatory support:
Through any open stopcock or port on central line
Through an IV or infusion line
During insertion/changing of a central line with an open port. Be sure there are no signs of suction during
insertion of a central line.
Through any loose connection point on the system circuit
Avoid conditions that may result in suction, line chatter, or shaking.
CentriMag System Assessment and Adjustments
Pump speed and alarm settings must be assessed frequently and manually adjusted when necessary. Speed changes should be
gradual while monitoring the changes in available volume and the resultant hemodynamic effects.
Ensure that you clamp the return tubing prior to turning off the pump or reducing set speed below 1000 RPM to avoid retrograde
flow. Pump flow (LPM) and speed (RPM) should be recorded with vital signs on the patient’s chart to trend hemodynamic change
with the pump parameters.
Table 4. Target pump and clinical conditions
Parameter
Value
CentriMag pump
3000-4000 RPM
Pump flow
4-5 LPM
RAP and LAP
10-15 mmHg [8-12 mmHg after several stable days of support]
Mean arterial pressure
60-80 mmHg
Target ACT
160-180 seconds (after bleeding has subsided)
For biventricular support, the hemodynamic conditions of the pulmonary and systemic circulations should be balanced. To do this,
manage the RVAD flow relative to the LVAD flow. Increase or decrease the RVAD set speed gradually, in 50-100 RPM increments every few
seconds, allowing the patient’s vascular system to adjust between each RPM change. The pump set speed should be gradually increased to
the desired flow. If flow drops or tubing chatter is observed, the set speed should be immediately reduced 100-200 RPM. Once target
flows are acquired, if changes are necessary to one of either the LVAD or RVAD flows, ensure that the other is also changed accordingly.
CAUTION: If the RVAD speed is increased but no change in the LVAD flow is observed, a pulmonary edema may be present.
Decrease the RVAD set speed, and increase the LVAD set speed as needed to balance appropriately.
CAUTION: If the LVAD speed is increased without adjusting the RVAD speed, risk of LV suction may occur.
Normally the left heart output is slightly greater than the right heart due to natural shunting. When providing maximal support, the
right and left pump flows should be nearly equal, but may vary as much as 0.5 LPM to 1.0 LPM, with the left side support usually
being greater. The factors that affect this difference are the valvular incompetence, and ventricular ejection through the pulmonic or
aortic valves, that is not reflected in the VAD flow. Generally, the right flow should not greatly exceed the left flow.
WARNING: A high RVAD pulmonary flow without a corresponding high LVAD systemic flow may result in pulmonary edema.
The position of the flow probe should be such that it does not cause kinking of the tubing. If positioned close to the pump, the weight
of the flow probe may cause a kink in the tubing near the inlet or outlet of the pump. Moving the probe further away from the pump will
usually resolve this. Repositioning the flow probe on the tubing line periodically to maintain accuracy and avoid kinking of tubing is
recommended.
Periodic checks should be performed to ensure:
There is no entrained air.
There are no clots at tubing connections to the cannulas and pump. A flashlight can be used to inspect.
Cannulas are secured to the patient.
Tubing is free of sharp bends or kinks.
The console is on AC power.
The battery is fully charged.
An additional console is available to use as a backup console.
6
Actual patient values will vary significantly based on individual needs and hemodynamic condition.
