[Nitric oxide delivery through ventilator and its toxic oxidative product nitrogen dioxide]

To observe nitric oxide(NO) delivery through mechanically ventilator. NO is rapidly converted to nitrogen dioxide(NO2)in oxygen(O2) environments.

NO(800 ppm)was blended with compressed air, delivered to the high-pressure air inlet of a Siemens Servo 900C or VIP BIRD ventilator, and used to ventilator as a test lung. The ventilator settings were varied, minute ventilation (VE)from 2 to 6 L/min, inspired O2 fraction(FiO2)from 0.25 to 0.65, and NO concentration from 10 to 80 ppm. The inspiratory gas mixture was sampled just at the outlet port of ventilator. NO and NO2 were measured both by hemiluminescence and electro-chemical fuel cell technique.

No NO was detected during any trial with VE 5 or 6 L/min., with FiO2 0.35 or 0.25, with NO 20 or 10 ppm. Low VE and low NO, NO2 values were greater with Servo 900C ventilator than with VIP BIRD ventilator at similar settings High VE and low NO or low VE and high NO, NO2 values were similar with both ventilators. High VE and high NO, NO2 values were greater with VIP BIRD ventilator than with Servo 900C ventilator. At same VE, NO2 values increased with increased FiO2 and NO. (NO2) = 0.0607 (NO)- 0.6604 VE + 7.004 FiO2, R2 = 0.7649 with Servo 900C ventilator,(NO2) = 0.0929(NO)- 0.1296 VE + 7.9360 FiO2, R2 = 0.8687 with VIP BIRD ventilator.

NO(800 ppm) was blended with compressed air, delivered to the high-pressure air inlet of a Siemens Servo 900C or VIP BIRD ventilator is a portable, accurate, and adaptable system to deliver NO. During NO inhalation, VIP BIRD ventilator is more adaptable while low VE. Servo 900C ventilator is more adaptable while high VE.