Factors Associated With Failure of High-Flow Nasal Cannula

The use of high-flow nasal cannula (HFNC) is rapidly increasing without clear indications, creating the potential for overuse or misuse and the accompanying risk of adverse events. The purpose of this study was to determine the factors associated with HFNC failure by examining the current clinical practice of HFNC.

From July 1, 2017, to June 30, 2018, in 5 university-affiliated hospitals in the Republic of Korea, a total of 1,161 admitted adult subjects who had HFNC administered were retrospectively enrolled and their medical records were reviewed.

Pulmonary diseases including pneumonia (n = 757, 65.2%) were the most common reason for use of HFNC. Subjects with do-not-resuscitate (DNR) or do-not-intubate (DNI) orders comprised 33.8% of the study population (n = 392); 563 subjects (48.5%) were escalated directly to HFNC from low-flow devices without applying reservoir or other high-flow devices. In the non-DNR/DNI subjects, arterial blood gas was not monitored in 15.2% and 14.8% of subjects before and after HFNC application, respectively, and it was not monitored in 28.0% just before HFNC weaning. The HFNC failure rate was 27.0% in non-DNR/DNI subjects, and the HFNC failure was significantly associated with the decision by residents to apply HFNC (odds ratio [OR] 2.03, 95% CI 1.29-3.18, P = .002), high breathing frequency (OR 1.07, 95% CI 1.04-1.10, P < .001) ≤ 6 h before HFNC application, low [Formula: see text] (OR 0.92, 95% CI 0.89-0.95, P < .001) ≤ 6 h before HFNC application, low [Formula: see text] (OR 0.95, 95% CI 0.93-0.98, P < .001) ≤ 6 h before HFNC application, and the ratio of [Formula: see text]/[Formula: see text] to breathing frequency (ROX index) ≤ 6 h after HFNC application (OR 0.88, 95% CI 0.84-0.92, P < .001).

HFNC was practiced without applying reservoir or other high-flow devices before application and without appropriate arterial blood gas monitoring during HFNC therapy. HFNC failure was significantly associated with the decision by the resident to use HFNC, breathing frequency, [Formula: see text], and [Formula: see text] ≤ 6 h before HFNC application, and with the ROX index ≤ 6 h after HFNC application.