In a patient on extracorporeal membrane oxygenation (ECMO) and Impella ventricular assist device who has a flat arterial line waveform, hypotension with MAP 63 mm Hg and no pulsatile flow, what is the next step?

Immediate Management of ECPELLA Patient with Flat Arterial Line and Loss of Pulsatility

Immediately activate your cardiac arrest team (call 2222), split into two teams—one for ECMO troubleshooting and one for patient assessment—and begin systematic device troubleshooting while preparing for potential CPR, as your patient has inadequate circulation (MAP 63 mmHg is above the cardiac arrest threshold of <30 mmHg but below adequate circulation of >55 mmHg). 1

Critical First Actions (Complete Within Minutes)

1. Verify Your Arterial Line is Functioning

• The flat waveform may be a monitoring artifact—confirm the transducer is properly leveled and functioning
• Check for damping, air bubbles, or kinked tubing in the arterial line itself
• Your MAP of 63 mmHg suggests some perfusion is occurring despite the flat waveform 1

2. Immediately Assess ECMO Flow

• Check the ECMO console for actual flow readings
• Ensure the flow sensor is correctly oriented and programmed interventions are reset
• If ECMO flow is >2 L/min: Proceed to next troubleshooting steps
• If ECMO flow is <2 L/min: You have access insufficiency—reduce RPMs until suction resolves, then gradually increase to highest tolerated flow. Give 2.5 ml/kg crystalloid bolus 1
• If ECMO shows NO FLOW: This is critical—immediately clamp the return line to the patient 1

3. Expose Patient and Inspect Entire Circuit

• Look for visible color change between drainage and return tubes (confirms oxygenation)
• Straighten any kinked tubing
• Assess cannula position—reposition patient to supine if needed
• Check for circuit rupture or accidental decannulation 1

4. Verify Gas Flow to Oxygenator

• Manually check the entire gas line pathway
• Confirm connection at both flow meter and oxygenator
• Verify flow is present—a depleted oxygen cylinder is a repeatedly reported error 1

ECPELLA-Specific Management

Increase the Impella P-level setting if able and follow your institution's Impella-specific algorithm. 1 The loss of pulsatility with a flat arterial line in an ECPELLA configuration suggests:

• Possible LV distention from inadequate Impella unloading with excessive ECMO afterload
• Native cardiac function may be severely depressed or arrested
• The Impella may be malpositioned or have reduced flow

Optimize Impella Function:

• Verify Impella position on bedside echo or fluoroscopy if immediately available
• Increase P-level to maximum tolerated (typically P-8 or P-9 for CP)
• Check Impella console for flow readings and alarms
• Assess for suction events or low flow warnings 2, 3

Hemodynamic Assessment and Targets

Your patient currently has inadequate circulation based on the 2025 British ECMO guidelines:

• MAP 63 mmHg (need >55 mmHg for adequate circulation)
• Unknown ECMO flow (need >2 L/min)
• Unknown oxygen saturations (need >88%) 1

Immediate Diagnostic Steps:

• Obtain arterial blood gas for lactate and mixed venous saturation
• Check pulse oximetry
• If pulmonary artery catheter present: assess cardiac output, pulmonary artery pulsatility index, and right atrial pressure 4
• Perform bedside echocardiography to assess:
  • LV distention (suggests inadequate unloading)
  • RV function and position
  • Cannula positions
  • Tamponade
  • Impella position 1

Critical Decision Points

If MAP Drops Below 30 mmHg with No ECMO Flow and No Recordable Saturations:

Start CPR immediately. 1 There is no evidence that CPR is harmful to ECMO patients with inadequate circulation.

If Patient is <10 Days Post-Sternotomy:

Consider emergent re-sternotomy 1

If Troubleshooting Fails to Restore Adequate Circulation:

• Maximize ECMO flows to highest tolerated level
• Maximize Impella support (increase P-level)
• Consider causes of low flow: bleeding (activate massive transfusion protocol, reverse anticoagulation), tamponade, cannula malposition 1

Common Pitfalls to Avoid

1. Don't assume the flat arterial line represents true hemodynamics—verify with alternative monitoring (echo, ETCO2, pulse ox, blood gases)
2. Don't give standard cardiac arrest dose epinephrine immediately—if device troubleshooting can quickly restore flow, epinephrine-induced hypertension may worsen outcomes. Use reduced dosing or infusions if needed 1
3. Don't overlook gas flow to the oxygenator—many ECMO devices lack alarms for this 1
4. Don't fluid overload assuming "RV preload dependence"—the RV prefers euvolemia with CVP 8-12 mmHg 5

No Flow Scenarios (If Confirmed)

If you confirm true no flow on ECMO, immediately address one of four critical problems:

1. Air embolus: De-air using built-in side ports, identify air source
2. Motor failure: Transition to new pump/console (hand crank if needed)
3. Accidental decannulation: Activate ECPR protocol for rapid recannulation
4. Circuit rupture: Emergency circuit change per institutional protocol 1

After resolving any issue, ensure pump interventions are reset on console to reinitiate flow. 1