High-flow nasal cannula therapy reduced the respiratory rate and respiratory distress in a standard model simulator and in patients with hypoxemic respiratory failure.

High-flow nasal cannula (HFNC) therapy has been increasingly applied to treat patients with severe hypoxemic respiratory failure. We investigated whether vital signs reflect the reduction of work of breathing in a simulator study and a clinical study. In the simulator study, a standard model high-fidelity human patient simulator (HPS) directly received 35 L/minute of 100% O2 via the HFNC. In the clinical study, the medical records of patients with hypoxemic respiratory failure who received HFNC therapy between January 2013 and May 2015 were retrospectively reviewed. Statistical analysis was performed using a one-way repeated analysis of variance followed by Bonferroni post-hoc testing. In the HPS, HFNC therapy significantly reduced the partial pressure of alveolar CO2, respiratory rate, and tidal volume (p < 0.001), and all values returned to baseline following HFNC therapy termination (p < 0.001). In the clinical study including 48 patients, the respiratory rate was significantly reduced from 27 ± 9 (baseline) to 24 ± 8 (3 hours), 24 ± 8 (5 hours), and 24 ± 8.0 (6 hours) (p < 0.05). The heart rate also decreased significantly (p < 0.05). Our results suggested that HFNC therapy reduced work of breathing and assessing vital signs can be important.