Risk Factors for ICU Admission for Anthracycline-exposed Pediatric Oncology Patients

Background: Pediatric oncology patients are commonly admitted to the pediatric intensive care unit (PICU) during and following cancer treatment and represent a disproportionate amount of PICU mortality. Anthracyclines are a frequently administered class of chemotherapeutic medications with known toxic effects on cardiovascular function. Despite this, risk factors for PICU admission in the anthracycline-exposed pediatric oncology population are not well-described. Hypothesis: Anthracycline-exposed pediatric oncology patients who are admitted to the PICU are more likely to have cardiac dysfunction than those patients not admitted to the PICU. Methods: Retrospective, parallel cohort study of children with oncologic diagnoses who received anthracyclines between January 2006 and December 2014 and were admitted to the hospital within one year of completion of therapy. Patients admitted to the PICU and those admitted to a non-PICU setting were compared. Primary outcome was presence of cardiac dysfunction (CD) at the time of hospital admission. Secondary outcomes included one-year mortality and hospital length of stay (LOS) as well as respiratory and cardiovascular support, medications and infectious data during the admission. Results: The charts of 734 patients were reviewed. 189 patients were excluded, leaving 545 patients with eligible hospital admissions. 219 patients (40%) were admitted to the PICU at least once within one year of completion of anthracycline therapy. The children admitted to the PICU were older (9.3 vs 7.5 years, p 0.001) and most commonly admitted with hypotension (37%) compared with the children not admitted to the PICU. Those not admitted to the PICU were most commonly admitted to the oncology service with fever, without evidence of shock (76%). Children admitted to the PICU were significantly more likely to have CD at the time of hospital admission (12% vs 1%, p < 0.001). They also were most likely to have undergone stem cell transplantation (9% vs 2%, p 0.002) and have received higher cumulative anthracycline doses (138 vs 90 mg/m2). Children admitted to the PICU had higher mortality rates within one year of completing anthracycline therapy (22% vs 3%, p < 0.001), had significantly longer hospital LOS (7 vs 2 days) and had a greater incidence of identified infection (45% vs 24%, p < 0.001). Once admitted to the PICU, children with CD have significantly higher rates of mortality (28% vs 5%, p < 0.001), longer LOS (13 vs 7 days, p 0.002), fewer ventilator-free days (0 vs 24 at 28 days, p < 0.001) and higher requirements for vasoactive medications (vasoactive inotrope score 27.5 vs 10, p <0.001) than their critically-ill, anthracycline-exposed counterparts without CD. Conclusions: Anthracycline-exposed pediatric oncology patients often experience critical illness during treatment of their cancer. Those critically ill children are more likely to have CD at the time of admission and higher morbidity and mortality.