Electrically generated nitric oxide from air: a safe and economical treatment for pulmonary hypertension

Excerpt

Inhaled nitric oxide (NO) is a selective pulmonary vasodilator approved by the US Food and Drug Administration in 1999 for the treatment of persistent pulmonary hypertension of the newborn [1]. The current NO delivery system is large, heavy, cumbersome and expensive, requires a cylinder distribution network and a device to regulate NO levels, monitor nitrogen dioxide (NO₂), percent of O₂, and trained respiratory therapy staff. Several methods have been used to produce NO for biomedical applications, including chemical and electrical systems. However, these methods produce large amounts of NO₂ and ozone (O₃) toxic byproducts, requiring complex purification systems. Recently, we designed, developed, and tested a lightweight, portable, economical device generating NO by pulsed electrical discharge in air using a high-voltage resonant power supply, to produce low levels of NO₂ and O₃ [2]. The electrodes are powered by a microcontroller circuit. Energy is stored and released by an autotransformer and delivered to the spark gap to create a plasma. The levels of NO can be controlled by electrical variables. Our previous studies demonstrated that NO can be generated continuously and stably by one set of electrodes at a desired concentration for at least 1 month [2]. We selected iridium electrodes for NO generation to reduce the level of NO₂ when compared to other metal electrodes. Using a 12-g scavenger, we removed NO₂ and O₃, and demonstrated that the electrical plasma NO generator stably produces safe therapeutic levels of inhaled NO from air [3]. Recently, we have developed a novel miniaturized version of the device for an infant, weighing about 14-g and safely producing therapeutic levels of NO from air [4]. Several advantages of using electrically generated NO include (1) lightweight (versus a cylinder), which makes possible ambulatory applications, such as in remote areas or the battle field, (2) relatively low power is needed to generate desired concentrations of NO gas (e.g. power 5–6 watts for 80 ppm NO), which makes it possible to power the device by batteries, (3) economical, which will enable increased accessibility to NO treatment, including patients in developing countries (Table 1). Several pre-clinical studies have been completed to confirm the effectiveness, safety, and feasibility of electrically generated NO (described in the ESM). …