VV ECMO in ARDS Patients Post-Hematopoietic Stem Cell Transplant (HSCT)
Background
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Advances in hematological disease treatment: HSCT, CAR-T, biologics → improved prognosis.
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Simultaneous progress in critical care & ARDS management (ARDSNet strategies, fluid restriction, transfusion reduction).
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Despite progress, subset of patients develop refractory hypoxemia/hypercapnia → ECMO considered.
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Fragile population: increased risks of bleeding, infection, neutropenia, organ dysfunction, altered drug kinetics.
Mortality & Prognosis
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Historically, ICU mortality for HSCT patients with ARDS very high (58–70%).
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Since 2010, outcomes improved with aggressive ICU support.
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Large Franco-Belgian multicenter study (>1,000 patients):
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Early ICU admission strongly linked to survival.
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Survivors at hospital discharge had ~100% 24-month survival.
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Prognosis worse after allogeneic vs autologous transplant (higher infection/sepsis risk).
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1-year mortality post-allogeneic HSCT still ~67%.
Recent Evidence
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Long-term mortality remains high, especially with prolonged ICU stay (>28 days), multiple organ support, or vasopressor use.
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Studies show outcomes depend on:
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Type of transplant (autologous > allogeneic).
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Timing of respiratory failure (early graft dysfunction = poor prognosis).
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Underlying disease remission vs relapse.
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Number of organ failures (multi-organ failure = poor candidate).
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ECMO-Specific Considerations
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Patient selection is critical: avoid cases with uncertain prognosis, graft failure, uncontrolled infections, GVHD.
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Indications/criteria:
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Refractory hypoxemia (PaO₂/FiO₂ < 60 for >3h).
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Mechanical ventilation ≤7 days.
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Severe respiratory failure despite optimal care.
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Contraindications/poor candidates:
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Early graft dysfunction, severe GVHD, uncontrolled fungal infection, multi-organ failure.
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Complications:
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Higher bleeding risk (low platelets, anticoagulation).
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ECMO may worsen immunosuppression/infections.
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Drug absorption/PK during ECMO not fully understood, esp. chemotherapy.
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Key Studies
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2014 (Wal et al.): first uniform series (14 hematological patients on ECMO) → feasible, survival possible in selected patients.
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2022 (Kak et al.): highlighted prognostic “red flags”: low platelets, high lactate, progressive disease.
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Position papers (ELSO/EuroELSO, oncology experts) → 36 statements guiding ECMO in HSCT/oncology; most reached strong consensus.
Practical & Ethical Lessons
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Multidisciplinary decision-making essential (ICU, oncology, hematology, nephrology, infectious disease).
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Involve family and patients early, ensure realistic expectations.
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Consider financial/resource implications.
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Use scores (RESP, PRESERVE) but weigh heavily immunosuppressed status.
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Anticoagulation: heparin standard; bivalirudin increasingly used. Platelet transfusion thresholds lower (≥20k often accepted).
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Focus on neurological/functional recovery & quality of life, not just hospital discharge.
Take-Home Messages
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VV ECMO can be life-saving in carefully selected HSCT patients with ARDS.
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Outcomes hinge on:
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Patient selection.
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Early intervention.
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Minimizing complications (bleeding, infection).
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Institutional expertise and resources.
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ECMO should be considered rescue therapy, not routine, in this fragile population.
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Goal: meaningful long-term survival with good neurological and functional recovery, not just survival to ICU discharge.