Intensive care unit (ICU) survival of cancer patients has improved. Urgent chemotherapy has become feasible in critically ill patients with specific organ dysfunction due to hematological malignancies.

The aim of the study was to assess ICU mortality rates and the factors associated with mortality in patients with hematologic malignancies receiving urgent chemotherapy in the ICU.

We retrospectively included all patients admitted to the ICU who received chemotherapy due to hematologic malignancy in 2012–2022.

Of the 129 patients undergoing chemotherapy in the ICU, 50 (38.7 %) died during the ICU follow-up. The following conditions were significantly more common among nonsurvivors: presence of infection at the time of ICU admission (p < 0.001), the requirement for mechanical ventilation during ICU stay (p < 0.001), the need for noninvasive mechanical ventilation during ICU stay (p = 0.014), vasopressor support (p < 0.001), and sepsis (p < 0.001). Logistic regression analysis revealed that among laboratory parameters on ICU admission, lactate (p = 0.008), albumin (p = 0.022), C-reactive protein (p = 0.046), baseline sequential organ failure assessment (SOFA) score (p < 0.001), newly developed heart failure (p = 0.006), and the requirement for vasopressor agents during ICU stay (p < 0.001) significantly influenced the risk of mortality in the univariate analysis. The multivariate analysis revealed lactate levels (p = 0.047) on ICU admission as an independent predictor of mortality.

The development of heart failure and lactate levels on admission were the main predictors of mortality. Additionally, higher SOFA scores revealed that illness severity was closely associated with mortality. Future studies should focus on strategies to further reduce these risks and achieve the best outcomes for these patients.