LAUSR

High flow nasal cannula(HFNC) has been used wildly last decades. However, the criteria for using, weaning and stopping have not been mentioned. In 2016, Oriol Roca et. al first published an index- ROX, which can predict whether the patient will fail to use HFNC in pneumonia patients. Our study wants to know if it can use in all kinds of patients. Our retrospective study was conducted in the medical intensive care unit. Patients who encountered respiratory failure again within 72 hours after extubation were included. After using HFNC still, have respiratory failure conditions who need non-invasive ventilators(NIV) or invasive ventilators are defined as HFNC failure group. Others are defined as success group. We exclude who use NIV before HFNC. In consequence, the failure group had greater respiratory rate and need more ventilator support than the success group. Also, the failure group had longer HFNC days, ICU days and hospital days. After that, we found a cut-off point at 12hrs, if ROX index greater than 8.635 then it tends to success on using HFNC. About ninety percent of patients9 ventilator-free days last for 28 days. ROX index can be used in post-extubation patients who suffer from respiratory failure again to predict the outcome of using it. It helps to set stopping criteria for using HFNC. We hope it can reduce delay treatment.