1) ECMO Clinical Phases
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Cannulation: candidate selection, cannula size/flow; lower initial shock severity → earlier weaning.
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Escalation (24–48h): resuscitate; faster lactate and organ marker clearance → earlier weaning.
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De-escalation/Weaning: ↓ flows, diurese, ↓ inotropes.
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Decannulation: echo-guided confirmation, then remove.
2) Plan Exit Early
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If recovery unlikely: consider LVAD/temporary VADs, VVA/VV ECMO, or palliation.
3) Readiness to Wean
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Stable MAP, CI, and falling inotropes.
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Pulse pressure returns/widens.
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Echo: improving LV/RV function.
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Perfusion markers: lactate and liver enzymes improving.
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Tidal CO₂ rise (>5 mmHg) may indicate native circulation returning.
4) Weaning Mechanics
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Maintain sweep (unlike VV).
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Gradually reduce ECMO flow (e.g., to 2–2.5 L/min); ensure anticoagulation at low flows.
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Before destination therapy, assess brain (awakening/CT).
5) Lung Readiness
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Perform oxygen challenge and ventilation assessment.
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If heart improves but lungs lag/Harlequin (north–south) appears → consider VVA or VV.
6) Ramp (ECBF Reduction) Study
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Method: reduce flow ~1 L steps over ~30–45 s; observe hemodynamics + echo.
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Abort if CVP rises, MAP falls, or instability.
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Hemodynamic targets: MAP ≥60 mmHg; pulse pressure ≥30 mmHg.
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Echo targets (at lowest flow):
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LVOT VTI >10 cm
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EF ≥25%
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LV not dilating
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Mitral lateral S’ ≥6 cm/s
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RV: no dilation or septal shift; coupling helpful
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S’ / RVSP >1/3 or TAPSE / RVSP >1/2
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7) Decannulation Trial
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Option A: Clamp ECMO ~5 min with echo.
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Option B: PCRTO (retrograde trial-off) to avoid clotting.
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If ramp passes: keep low flow (~2 L/min) overnight, then decannulate.
8) If Ramp Fails or Gray Zone
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Re-optimize (preload/afterload, gas exchange, revascularize, vent LV as needed) and retry.
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If multi-organ failure: consider one-way decannulation after goals-of-care discussion.
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If single-ventricle failure persists: bridge to LVAD/transplant.
9) Case Pearls
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Post-RV infarct: successful wean when RV tolerated preload, AV opened, PP >30, EF ~45%.
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Post-surgery RV failure: abort ramp if RV dilates/septum shifts at modest flow.
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Central VA with LV apical vent: clamp RA drainage to test RV; rising LV vent flow indicates readiness to convert ECMO→LVAD, then durable HeartMate 3.