Outcome and Prognostic Factors of Patients with Hematological Malignancies Admitted to an Intensive Care Unit
Authors: Lui Pak Ling , Pandey Rakshya , Koh Jonathan Tian En , Yap Eng Soo , Mukhopadhyay Amartya , Chng Wee Joo 
Published: October 2019

Abstract
Background
Patients with hematological malignancies (HM) often develop complications due to their treatment or their underlying disease, requiring admission to an intensive care unit (ICU). Historically, it has been believed that the outcome of these patients were poor. However, there is emerging evidence showing improvements in ICU outcome for patients with HM, as well as for other patients with critical illness. This study aimed to study the outcomes and prognostic factors for patients with HM admitted to the ICU of a tertiary hospital in Asia.
Methods
We reviewed the case records of consecutive ICU admissions for patients under the hematology service in our institution, from July 2010 to June 2014. Patients who did not have a HM and those who were admitted for monitoring following an elective procedure were excluded. Clinical information was gathered, including details of their HM, co-morbidities, clinical status on admission to ICU, laboratory measurements, and treatment received in ICU. Sepsis-related Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores were calculated. These were all evaluated for association with the primary outcome of survival to ICU discharge.
Results
A total of 288 admission episodes were reviewed, of which 264 were included for analysis. Of the excluded patients, 23 did not have a HM, and 1 was admitted following elective surgery. Overall ICU mortality was 34.8%, and overall hospital mortality was 45.8%. The mean duration of ICU stay was 5.3 days.
The type of HM did not significantly affect the outcome (P = 0.87), nor did the presence of relapsed/refractory disease (P = 0.38). Neutropenia (< 1 x 109 /L) was associated with higher mortality (P = 0.02), as was the presence of a positive blood culture (P = 0.002). (Table 1)
The use of red blood cell (P = 0.58) and platelet transfusions (P = 0.10) did not significantly affect the outcome. Patients who required the use of mechanical ventilation (P < 0.001) and vasopressor drugs (P < 0.001) did worse, but those who required the use of renal replacement therapy (P = 0.57) did not.
Higher SOFA and APACHE II scores were both associated with higher rates of ICU mortality (both P < 0.001).
Among the laboratory measurements on admission, platelet count, bilirubin, and aspartate aminotransferase (AST) were significantly different between survivors and non-survivors, while there were no significant differences in hemoglobin, white blood cell (WBC) count, sodium, potassium, urea, creatinine, and alanine aminotransferase (ALT) between the two groups.
The 9 variables that were found to be significant with P < 0.05 were analyzed in a multivariable logistic regression model. APACHE II score (P < 0.001), use of mechanical ventilation (P = 0.003), use of vasopressor drugs (P < 0.001), and serum bilirubin (P = 0.004) were found to be independently associated with ICU mortality.
Conclusion
Patients with HM requiring ICU admission in our study had comparable survival to previous published studies. Physiological parameters and indicators of organ dysfunction at the point of ICU admission were predictors of ICU mortality. The type of HM and the presence of refractory disease did not have a significant effect on ICU outcome. This information can also help to determine which patients would benefit most from intensive care, which remains a costly and limited resource. The results also suggest that patients should not be denied ICU admission solely based on the status of their HM.

Disclosures
No relevant conflicts of interest to declare.