What level should the Impella (Intra-Aortic Balloon Pump) be set to during cardiac arrest?

Impella P-Level Settings During Cardiac Arrest

During cardiac arrest, the Impella device should be set to P8 (maximum flow) to provide optimal hemodynamic support and increase the chances of return of spontaneous circulation.

Understanding Impella Support During Cardiac Arrest

• The Impella is a percutaneous ventricular assist device that provides mechanical circulatory support by propelling blood from the left ventricle into the systemic circulation 1
• Different Impella models provide varying levels of support: Impella 2.5 provides up to 2.5 L/min, while the Impella CP can provide up to 3.5 L/min of cardiac output 2
• During cardiac arrest, maximizing circulatory support is critical to maintain organ perfusion while addressing the underlying cause 1

Rationale for Maximum P-Level Setting

• Setting the Impella to P8 (maximum flow) during cardiac arrest provides the highest possible mechanical circulatory support to maintain vital organ perfusion 3
• Case reports demonstrate that maximum Impella support can achieve return of spontaneous circulation within minutes when conventional CPR is failing 4
• Higher flow rates (up to 3.5 L/min with Impella CP) have been associated with improved outcomes compared to lower flow rates in critically ill patients 2

Integration with Standard ACLS Protocols

• Standard ACLS protocols should be initiated simultaneously, including high-quality chest compressions at a rate of 100-120/min and a depth of 5-6 cm 5
• Chest compressions should be minimally interrupted, with a target chest compression fraction of at least 60% 5
• Mechanical CPR devices may be considered to provide consistent compressions while the Impella is being placed or adjusted 1

Special Considerations

• Anticoagulation is required with Impella devices to prevent pump thrombosis, typically with an initial unfractionated heparin bolus of 100 U/kg (up to 5000 U maximum) 3
• Echocardiographic guidance is recommended for optimal positioning of the Impella device during placement 3
• Vascular complications are more common with Impella compared to IABP (9.8% vs 3.8%), requiring careful attention to access site management 3

Outcomes and Limitations

• In a single-center study, patients who had Impella CP placed during active CPR had an in-hospital mortality rate of 86%, indicating that while this approach may be life-saving in select cases, outcomes remain poor 6
• Early Impella implantation after cardiac arrest might provide better cardiac support and tissue perfusion until recovery or definitive treatment 7
• For patients with severe cardiogenic shock not responding to Impella support, escalation to VA-ECMO or consideration of combined Impella and VA-ECMO support may be necessary 5

Practical Algorithm for Impella Management During Cardiac Arrest

1. Initiate standard ACLS protocols including high-quality CPR 5
2. Place Impella device as soon as feasible if available 7
3. Set Impella to P8 (maximum flow) immediately upon placement 1
4. Administer anticoagulation per protocol (UFH bolus 100 U/kg) 3
5. Monitor device position with echocardiography when possible 3
6. Address reversible causes of arrest while maintaining Impella support 5
7. If no return of spontaneous circulation within 30 minutes despite maximum support, consider escalation to VA-ECMO if available 5