Assessment of differences in pressure and comfort using different devices
EEP
The EEP, EIP, actual flow in the pipeline and comfort were evaluated with the use of different devices. The participant underwent a trial with each of the two HFNC devices (the flow rate was set to 0, 10, 20, 30, 40, 50, and 60 L/min) and a 4-mm cannula. The pressure of each flow rate in the pipeline was recorded continuously for 2 minutes, with a 5-minute interval between different flow rates (elution period). After each flow rate was measured, a visual analogue rating scale was used to determine the score. The actual output flow was measured in the pipeline using a Thermal mass flowmeter (TSI 5300; TSI Incorporated, Shoreview, MN, USA) installed in the respiratory hose in front of the nasal catheter. The above process was repeated with the other device 24hous later (washout period). The order of using the two devices was random. The nasal catheters and anesthesia catheters were removed during the washout period.