Early Predictors of High-Flow Nasal Cannula Oxygen Therapy Failure in the Emergency Room

Eun, Seung Wan; Kim, Tae Kwon; Jeon, Jae Cheon; Jin, Sang Chan; Choi, Woo Ik

Abstract

High flow nasal cannula (HFNC) oxygen therapy has become a substitute for other non-invasive ventilation (NIV) and mechanical ventilation in patients with respiratory failure. Despite its strong points, HFNC may result in failure of therapy, and delayed intubation leads to poor patient outcomes. This study is aimed to identify the variables that predicts HFNC oxygen therapy failure in order to increment success rate and prevent delayed intubation. The study was conducted in a retrospective manner, enrolling all non-traumatic patients over the age 20 who visited a single university-affiliated tertiary medical center emergency room and were treated with HFNC between March 1, 2016 to Feburary 28, 2017. Patients were classified into two groups: HFNC success group, and HFNC failure group: HFNC failure group was defined as patients who were treated with HFNC, and resulted in intubation and mechanical ventilation, or death. General characteristics, clinical features, and laboratory findings of the two groups were compared. Additionally, univariable logistic regression was done for statistically significant variables, and if the p-value was < 0.05, multivariable logistic regression analysis was conducted. 95 patients were enrolled in the study. Repeated-measure ANOVA was conducted for serial arterial blood gas samples during therapy. 62 patients were successful in the treatment, and the treatment failed in 33 cases. After multivariate logistic regression analysis, variable that showed statistically significant association with HFNC failure was initial hematocrits (p < 0.05). Repeated-measure ANOVA revealed low bicarbonate as a predictor of HFNC failure. Predictors of HFNC therapy failure are initial hematocrits, bicarbonate levels during therapy.