Hyperlactatemia and Lactic Acidosis in Critically Ill Patients with Hematological Malignancies: A Single Center Retrospective Study

BackgroundHematological malignancies expose patients to lactic acidosis, either type A (mostly due to sepsis) or B (malignancy related). As information is scarce about lactic acidosis in this population, we aimed to describe its characteristics and impact on outcome.MethodsRetrospective chart review of all patients with hematological malignancies admitted to the ICU and with lactates measured between 2008 and 2018. Hyperlactatemia and lactic acidosis were defined by blood lactate levels ≥ 2 and 4 mmol/L respectively.ResultsHyperlactatemia and lactic acidosis were present in 60% and 30% of the 666 patients included respectively and lactic acidosis was independently associated with hospital mortality (OR 2.00, 95% CI 1.02-3.87, p = 0.04). A cluster analysis in the whole population revealed 3 clusters of patients with prognostic implication: a first cluster was characterized by diverse hematological malignancies, low incidence of hyperlactatemia, low requirements for vital organ support and low mortality (14%). A second cluster included patients mostly with type A lactic acidosis due to septic shock or cardiac arrest, with severe multiorgan failure and extremely high mortality (87%), whereas the third cluster included patients frequently with lymphoma and no obvious cause for lactic acidosis and was characterized by less severe multiorgan failure and intermediate mortality (40%). Patients with type B lactic acidosis were more frequently male, with lymphoma, they had less severe hyperlactatemia, acidosis, acute kidney injury, they required less vital organ support and had lower mortality rate than type A acidosis (32.4% vs 77.2%, p < 0.001).ConclusionsLactic acidosis was frequent in ICU patients with hematological malignancies and associated with mortality. As a surrogate for type B acidosis, patients with no obvious cause for lactic acidosis and no vasopressor requirements had lower mortality than type A lactic acidosis.