Objective: To investigate the correct and safe use of pulse oximeters by the public and to contribute to their safe use in the future.

Methods: On April 1, 2022, non-healthcare professionals (citizens) were surveyed to determine whether they knew how to use a pulse oximeter, whether they knew the standard and abnormal values of SpO₂, and whether they had experienced any adverse events or perceived malfunctions.

Results: Responses were obtained from the 300. Of those who knew how to use the pulse oximeter, 77.1% correctly answered the standard value and 24.8% correctly answered the abnormal value. 44.0% of the respondents had experienced a failure of measurement, and 28.3% had experienced an adverse event or malfunction.

Conclusion: Although the government and academic societies provide information on usage and precautions, it is possible that the information is not reaching the citizens. In addition, since both adverse events caused by the method of use and those caused by the product have occurred, it is necessary to establish a support system.

High-frequency oscillatory (HFO) is a commonly used therapy applied to preterm infant who require ventilatory support for open lung. The authors have been developing a generator for Nasal-CPAP (HNCPAP) using an air-curtain capable controlling nasal-HFO. This paper describes Nasal-HFO pressure waveforms synchronized with spontaneous breathing from Nasal-HFO results. Experiments were conducted using a breathing mode simulating healthy lungs of a spontaneous breathing simulator for neonates, with MAP (mean airway pressure) constant, and without HFO and with HFO for each of tidal volume. The experimental conditions are MAP 500 Pa, respirator frequency 50 times/min, stroke volume 15 ml, tidal volume 2 ml, 5 ml, 7 ml. The results obtained were as follows: (1) HFO amplitude should not be attenuated in the airways, (2) HFO amplitude increased during inhalation further reduced alveolar pressure, and (3) Adding HFO in first half of exhalation halved the entrainment effect. From these results, Nasal-HFO pressure waveform were predicted.

・ By adding HFO during inhalation, the alveolar pressure was further reduced, and the lung recruitment effect was improved.

・ By eliminating HFO in the first half of exhalation, exhalation flow can be discharged without resistance using entrainment.

Finally, prediction of Nasal-HFO synchronized with spontaneous breathing showed the possibility of new use of HNCPAP.