Practice Test GeeksECMO - Extracorporeal Membrane Oxygenation Practice Test
← All ECMO Flashcard Decks

Physiology and Pathophysiology 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 Physiology and Pathophysiology flashcards as text

  1. What is the physiological mechanism by which ECMO improves coronary perfusion in cardiogenic shock?

    Answer: VA-ECMO raises aortic diastolic pressure, which is the primary determinant of coronary perfusion pressure

    Coronary perfusion occurs primarily during diastole and depends on aortic diastolic pressure; VA-ECMO's continuous retrograde flow elevates aortic diastolic pressure, improving coronary perfusion pressure.

  2. In a patient on peripheral VA-ECMO, which monitoring site best reflects cerebral oxygenation?

    Answer: Right radial arterial blood gas (pre-mixing zone)

    The right radial artery reflects blood ejected from the native heart before it mixes with retrograde ECMO flow, providing the best estimate of oxygen delivery to the brain and coronary arteries.

  3. How does systemic inflammatory response syndrome (SIRS) triggered by ECMO circuit contact activation alter vascular physiology?

    Answer: SIRS causes vasodilation and capillary leak, increasing volume requirements and reducing effective circulating volume

    Contact of blood with artificial circuit surfaces activates complement and inflammatory cascades, producing vasodilation and endothelial permeability that manifests as distributive physiology requiring volume resuscitation.

  4. What is the physiological basis for using prone positioning concurrently with VV-ECMO in severe ARDS?

    Answer: Prone positioning redistributes ventilation-perfusion matching and reduces dorsal alveolar overdistension, complementing ECMO's gas exchange support

    Prone positioning recruits dorsal lung regions, improves V/Q matching, and reduces cyclic alveolar stress, providing additive benefit to VV-ECMO's extracorporeal gas exchange in ARDS.

  5. A patient on VV-ECMO has SvO2 of 85% from the drainage cannula but SpO2 of 82%. What does this pattern indicate?

    Answer: High recirculation: oxygenated blood is being re-drained before reaching the systemic circulation

    When pre-membrane SvO2 (drainage cannula) is nearly as high as or higher than patient SpO2, a large fraction of blood draining into the circuit is already oxygenated, indicating recirculation rather than true mixed venous blood.

  6. Which coagulation abnormality is uniquely associated with ECMO and results from destruction of high-molecular-weight von Willebrand factor multimers?

    Answer: Acquired von Willebrand syndrome (AVWS)

    High shear stress generated by the ECMO pump cleaves large vWF multimers via ADAMTS-13, producing an acquired von Willebrand syndrome that impairs primary hemostasis and contributes to bleeding complications.

  7. Why does LV end-diastolic pressure rise during VA-ECMO in patients with severely impaired systolic function?

    Answer: Increased LV afterload from retrograde aortic flow impedes LV ejection, causing blood to accumulate in the ventricle

    VA-ECMO raises aortic pressure retrograde, increasing LV afterload; if the failing LV cannot eject against this pressure, stroke volume falls, residual volume accumulates, LVEDP rises, and pulmonary edema may worsen.