Early predictors of unresponsiveness to high-flow nasal cannula therapy in a pediatric emergency department.

Abstract

High-flow nasal cannula (HFNC) is a new treatment option for pediatric respiratory distress and we aimed to assess early predictive factors of unresponsiveness to HFNC therapy in a pediatric emergency department (ED). Patients who presented with respiratory distress and were treated by HFNC, were included. The age, gender, weight, medical history, diagnosis, vital signs, oxygen saturation/fraction of inspired oxygen (SpO2 /FiO2 ) ratio, modified Respiratory Distress Assessment Instrument (mRDAI) scores, medical interventions, duration of HFNC therapy, time to escalation, adverse effects, and laboratory test results were obtained from medical and nursing records. The requirement of a higher level of respiratory support due to unchanged or increased RR compared to initial RR, incipient, or progressive respiratory acidosis, incipient hemodynamic instability was defined as unresponsiveness to HFNC. The study enrolled 154 children with a median age of 10 months (interquartile range [IQR], 5.7-22.5 months). The diagnosis was acute bronchiolitis in 59 patients (38.3%), bacterial pneumonia in 64 patients (41.6%), and atypical or viral pneumonia in 31 patients (20.1%). Twenty-five patients (16.2%) were in the unresponsive group, and the median time for escalating respiratory support was 7 h (IQR: 4-20 h). The unresponsive group had lower SpO2 and SpO2 /FiO2 (SF) ratio on admission, lower venous pH, and higher partial pressure of carbon dioxide (pCO2 ) (P = 0.002, P = 0.012, and P = 0.001, respectively). Also the alteration of RR, mRDAI score, and SF ratio at the first hour was greater in the responsive group. The cut-off value of SF ratio at the first hour of HFNC was 195 for unresponsiveness. The low initial SpO2 and SF ratio, respiratory acidosis, and SF ratio less than 195 at the first hours of treatment were related to unresponsiveness to HFNC therapy in our pediatric emergency department.