Factors associated with high-flow nasal cannula failure

Background: High-flow nasal cannula(HFNC) is a recently developed oxygen(O2) supply device, and its use is rapidly increasing in clinical practice. However, studies for factors associated with HFNC outcome are very limited. Aims and Objectives: To evaluate the factors associated with HFNC failure. Methods: For the admitted patients from 1 July 2017 to 30 June 2018 in 5 university affiliated hospitals, we retrospectively reviewed medical records of 1,161 adult patients who were applied HFNC. Results: The mean age of the patients was 70.8 years old and 63% was male. Most were medical patients(n=1,014; 87.3%). The most common cause of O2 therapy was pulmonary diseases including pneumonia(65.2%). Do-Not-Resuscitate(DNR) patients were 33.8%. In the analysis of patients without DNR(n=769), the HFNC-failure rate was 27% and the hospital mortality was 21.1%. In multivariate analyses, HFNC-failure was significantly associated with O2 saturation just prior to HFNC, and lastly checked respiration rate(RR), pH and O2 saturation during HFNC(p<0.05). The factors associated with hospital mortality were O2 saturation and RR just prior to HFNC, and lastly checked RR, pH, HCO3- and HFNC-failure during HFNC(p<0.05). In Receiver Operating Characteristic(ROC) curve analysis for the associated factors of HFNC-failure, reliable cut off values of O2 saturation just prior to HFNC, and lastly checked RR, pH and O2 saturation during HFNC were 90.4%(AUC=0.633, p<0.001), 24/min(AUC=0.747, p<0.001), 7.365(AUC=0.732, p<0.001), and 94.1%(AUC=0.754, p<0.001), respectively. Conclusion: The parameters during HFNC are more associated with HFNC-failure and hospital mortality, indicating the importance of monitoring during HFNC.