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Veno-Venous (VV) ECMO Management Flashcards

7 cards from real ECMO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Veno-Venous (VV) ECMO Management flashcards as text

  1. A patient on VV ECMO has a pre-membrane pO2 of 35 mmHg and post-membrane pO2 of 450 mmHg, yet SpO2 remains at 78%. What is the most likely cause?

    Answer: High recirculation fraction

    High recirculation returns already-oxygenated blood back to the drainage cannula, reducing effective oxygen delivery despite excellent oxygenator function.

  2. Which intervention most directly reduces recirculation in a patient on dual-lumen bicaval VV ECMO?

    Answer: Repositioning the return jet away from the drainage port

    Directing the return jet toward the tricuspid valve and away from the drainage port minimizes recirculation of oxygenated blood.

  3. On VV ECMO, a patient's SaO2 is 88% with ECMO flow at 5 L/min. The native cardiac output is estimated at 8 L/min. What is the approximate recirculation fraction?

    Answer: 37%

    Recirculation fraction = (ECMO flow – effective flow) / ECMO flow; with total venous return mixed with ECMO flow, approximately 37% recirculation yields this oxygen delivery.

  4. Which blood gas parameter is MOST useful to assess oxygenator function independent of recirculation on VV ECMO?

    Answer: Post-membrane pO2

    Post-membrane pO2 directly reflects the oxygenator's gas exchange efficiency regardless of recirculation or native cardiac function.

  5. A VV ECMO patient develops sudden increase in transmembrane pressure gradient from 20 to 80 mmHg over 6 hours. What is the most likely cause?

    Answer: Thrombosis within the oxygenator

    Progressive clot formation within the oxygenator increases resistance to blood flow, causing the transmembrane pressure gradient to rise.

  6. During VV ECMO, the sweep gas FiO2 is increased from 0.6 to 1.0 but CO2 remains elevated. What adjustment should be made?

    Answer: Increase sweep gas flow rate

    CO2 removal on ECMO is primarily determined by sweep gas flow rate (not FiO2), so increasing sweep gas flow enhances CO2 elimination.

  7. Which patient position is generally preferred during VV ECMO to optimize oxygenation in refractory ARDS?

    Answer: Prone positioning

    Prone positioning improves V/Q matching and recruits dorsal lung regions, complementing VV ECMO support in refractory ARDS.