Critically ill allogeneic hematopoietic stem cell transplantation patients in the intensive care unit: reappraisal of actual prognosis

The outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT) patients has significantly improved over the past decade. Still, a significant number of patients require intensive care unit (ICU) management because of life-threatening complications. Literature from the 1990s reported extremely poor prognosis for critically ill allo-HSCT patients requiring ICU management. Recent data justify the use of ICU resources in hematologic patients. Yet, allo-HSCT remains an independent variable associated with mortality. However, outcomes in allo-HSCT patients have improved over time and many classic determinants of mortality have become irrelevant. The main actual prognostic factors are the need for mechanical ventilation, the presence of GvHD and the number of organ failures at ICU admission. Recently, the development of reduced-intensity conditioning regimens, early ICU admission and the increased use of noninvasive ventilation, combined with time effect and general advances in hematology, in allo-HSCT procedures and in ICU management have contributed to improve general outcome. A rational policy of ICU admission triage in these patients is very hard to define, as each decision for ICU admission is a case-by-case decision at patient bedside. The collaboration between hematologists and intensivists is crucial in this context.