Development of a portable nitric oxide inhalation equipment using pulsed arc discharge

Inhaled Nitric monoxide (iNO) has been considered as an effective therapy for pulmonary hypertension and Acute Respiratory Distress Syndrome (ARDS). This therapy utilizes the vasodilator effect of NO. However, in clinical environment, a gas cylinder of N
2
mixed with a high concentration of NO is currently used as a source of NO inhalation, which has high risk. This is because that when NO, leaked into the air from cylinder, oxidizes to nitrogen dioxide (No
2
), the NO
2
lead medical accident due to its toxic. In a previous study, an equipment was proposed to generate NO in on-site from air using pulsed arc discharge. However, it had some demerits: The equipment had large capacity and heavy weight, this is not suitable for emergency case. The device was equipped the activated carbon to remove NO
2
and the metal particle generated by pulsed arc discharge. The activated carbon normally has short lifetime which is also not suitable for medical device. In the paper, the goal is to develop a portable NO inhalation equipment that can be used as medical tool by downsizing the discharge reactor and suppressing NO
2
formation in discharge process. As a preliminary step, we investigated the NO generation characteristics in different discharge energy, pulse repetition rate, and reactor temperature. The target concentrations of NO and NO
2
were 15ppm and 0.12ppm, respectively. The experimental results showed that NO
2
was suppressed by keeping the reactor at a high temperature and increasing the discharge energy in single pulse. The amount of NO production was simply increased by increasing the pulse repetition rate. NO reached the target concentration with the pulse repetition rate of 30 pps.