ECMO Circuit Components: cannulas, tubing, pump, membrane oxygenator, pressure/flow monitors, and other additional components (Dr. Faten Farid)

ECMO Overview

  • Two ECMO types:

    • VV ECMO: For respiratory support

    • VA ECMO: For cardiac support

  • Circuit components: Include pump (centrifugal/roller), oxygenator, cannulas, heat exchanger

Cannulas & Technical Details

  • Biocompatible, wire-reinforced cannulas collapse for insertion, expand in position

  • Proper cannula sizing and placement (e.g., IVC for drainage) essential for adequate flow

  • Monitoring via ECMO consoles includes RPM, flow rate, and backup hand crank system

Oxygenator Function & Circuit Safety

  • Oxygenators:

    • Polypropylene for short-term

    • Polyimide for long-term

  • Heat exchanger regulates blood temperature

  • Vigilance required to prevent thrombus, air embolism, and disconnection

Circuit Monitoring Essentials

    • Low flow may suggest cannula size/clot issues

    • Non-invasive monitors detect air bubbles and trigger alarms

      Monitor flow, efficacy, harm:

  • Track pump speed, circuit pressures, gas flow

Pressure Monitoring

    • Pre-pump, post-pump pre-oxygenator, post-oxygenator

      Key pressures:

  • Rising delta pressure = resistance or obstruction

  • Emphasized trend monitoring over isolated readings

Oxygenator Monitoring

  • Check pre- and post-oxygenator PO₂ (>300–350 mmHg ideally)

  • Watch for recirculation or contamination that skews readings

  • Decline in efficacy suggests need for replacement

Safety & Complication Awareness

  • Monitor for bleeding, thrombosis, hemolysis

  • Use of alarms, bubble detectors, and battery backups is critical for safe operation

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