Development of the Novel FLOX Score to Assess Risk of Intubation in Children With Immunocompromising Conditions Receiving High Flow Nasal Cannula.

BACKGROUND: Heated, humidified, high-flow nasal cannula (HFNC) before intubation has been associated with increased mortality in children with immunocompromising conditions (ICC). OBJECTIVES: We sought to describe HFNC failure (intubation) rate and aimed to develop a novel score associated with HFNC failure. METHODS: This is a single center, retrospective cohort. Patients (aged 0-26 years) with ICCs who used HFNC between 2021 and 2023 were included. RESULTS: Forty-four (47.3%) of 93 included subjects failed HFNC. PICU mortality was 14% (n = 13). The median duration of HFNC was 18.7 h (IQR: 6.0, 40.4). We developed the novel FLOX ((flow in Liters/minute)/weight (kg)*FiO2) score. Median FLOX score was higher with HFNC failure at initiation (p = 0.04), 2 h (p = 0.03), 4 h (p = 0.05), and 6 h (p = 0.05). Adjusting for acuity, the odds of HFNC failure with a FLOX score (≥0.20) were as follows: Initiation OR = 2.5 (95%CI: 1.03, 5.9), p = 0.042); 2 h of HFNC, OR = 4.3 ((95%CI: 1.7, 10.9), p = 0.002); 4 h of HFNC, OR = 6.5 (95%CI: 2.5, 16.8), (p < 0.001); and 6 h of HFNC, OR = 4.9 (95%CI: 1.9, 12.7), (p = 0.001). CONCLUSION: In children with ICCs, almost half fail HFNC. Mortality was high in those who fail HFNC. The FLOX score, specifically a FLOX ≥ 0.20 is associated with increased odds of failing HFNC in our ICC cohort.