An Analysis of the Risk Factors for the Failure of Respiratory Support With High-flow Nasal Cannula Oxygen Therapy in Children with Acute Respiratory Dysfunction:a case-control study

Background:Different causes of acute respiratory insufficiency threaten the lives of pediatric patients, while High-flow nasal cannula oxygen therapy (HFNC) is a new type of non-invasive respiratory support technique that widely used in pediatric intensive care units (PICUs);however, improper use of HFNC is likely to bring adverse consequences to critically ill children.Our objective in this study was to identify the risk factors for the failure of HFNC, that can guide clinicians during managing of HFNC treatment correctly.Methods: Divided the patients into different categories: HFNC success group (237 patients), a 48 h failure group (112 patients), a 24 h failure group (84 patients), and a 2 h failure group (24 patients). The clinical indexes and the change trend in HFNC before and after treatment were dynamically observed in 67 pediatric patients. Risk factors for HFNC failure were determined using multivariate logistic regression analysis.Results:PRISM III score >4 points and PaCO2 >43 mmHg were risk factors for 48 h failure (OR were 4.064, 4.516, P<0.05); PaCO2 >43 mmHg was risk factors for 24 h failure (OR was 3.152, P<0.05); PRISM III score >6.5 points and PaCO2/PaO2 ratio >0.67 were risk factors for 2 h failure (OR were 27.977, 64.366, P<0.05) and the risk of HFNC failure increased more than 5 times when the oxygenation index decreased by >28% after 2 h of HFNC treatment, and the invasive mechanical ventilation time was statistically longer in the patients that upgraded from HFNC to invasive respiratory support than that of patients who received invasive respiratory support directly(P<0.05).Conclusions: The PRISM III score, PaCO2 and PaCO2/PaO2 ratio were risk factors for HFNC failure. Totally the shorter the failure time, the higher the values of the risk factors were, and the higher the failure risk of HFNC was. The change trend in oxygenation index before and after HFNC is a warning factor for early HFNC failure. And early HFNC failure might lead to prolonged invasive mechanical ventilation.