Impella Suction Alarm Management
The first step in responding to an Impella suction alarm is to verify adequate power supply and intact cable connections, then assess device positioning and patient hemodynamics. 1
Immediate Assessment Steps
Power and Connection Verification
- Check that all power cables are properly connected and confirm adequate battery power or AC power connection 1
- Verify the percutaneous lead is intact and not damaged 1
- This is the most common cause of alarms and should be ruled out first 2
Device Function Confirmation
- Place a stethoscope over the pump in the left upper abdomen to confirm the constant mechanical hum of proper functioning 2, 1
- Check for adequate arterial flow using clinical examination or Doppler if peripheral pulse is not palpable 1
- Patients who are comfortable, awake, oriented, and without evidence of heart failure are unlikely to have severe device malfunction 2
Understanding Suction Events
Mechanism and Causes
- Suction alarms occur when the device inlet becomes obstructed or malpositioned, despite high motor currents 3
- The Impella pulls blood from the left ventricle through an inlet area near the tip, and obstruction of this inlet triggers the alarm 3
- Common causes include device migration, hypovolemia, or positioning too deep into the ventricle causing ventricular wall contact 3
Troubleshooting Algorithm
If Alarm Persists After Power Verification
- Consider exchanging the controller for the backup controller according to MCS center recommendations 2, 1
- The patient or caregiver may be able to perform this exchange if they have received training 2
Assess for Positioning Issues
- Evaluate device position using fluoroscopy or echocardiography to ensure the inlet is not against the ventricular wall 3
- Verify the device has not migrated distally into the ventricle or proximally into the aorta 3
Evaluate Patient Hemodynamics
- Check for hypovolemia, which can cause ventricular collapse around the device inlet 3
- Assess mean arterial pressure (target >65 mmHg) and end-organ perfusion 3
- Monitor cardiac output and cardiac index measurements 3
Critical Alarm Management
When to Escalate Immediately
- Patients with persistent controller or pump malfunction despite troubleshooting require immediate evaluation at the nearest center with MCS experience 1
- If the patient is unstable, transport to the nearest hospital for stabilization 1
- Critical alarms indicate impending loss of hemodynamic support and require immediate assessment and action 2, 1
Transport Considerations
- Avoid excessive tension on the percutaneous lead, which can result in device malfunction or exit-site trauma 2, 1
- Avoid kinking or cutting the percutaneous lead if clothing needs to be removed 2
- Transport all peripheral equipment with the patient: backup batteries, backup controller, universal battery charger, and AC power charger 2, 1
Collaboration and Communication
MCS Center Involvement
- Always manage care in collaboration with the MCS center in the setting of pump failure 1
- Frequently, advisory alarms can be assessed by telephone without the need for transport to the implanting center 2
- However, suction alarms accompanied by clinical symptoms or changes in pump parameters should be treated as critical alarms 2
Common Pitfalls to Avoid
Anticoagulation Considerations
- Ensure therapeutic anticoagulation is maintained (initial UFH bolus 100 U/kg, up to 5000 U maximum) to prevent pump thrombosis 3
- Subtherapeutic anticoagulation can lead to acute intraventricular thrombosis and device failure 4
- Device failure from thrombosis has been reported as early as 27 hours after implantation 4