[Evaluation of a new nitric oxide delivery system during mechanical ventilation]

A new nitric oxide delivery and continuous monitoring system is described. During mechanical ventilation, this new system connected with Siemens Servo 900C ventilator was shown to be able to provide a constant inspired NO concentration (10-100 ppm) using chemiluminescence technique for NO analysis. Gas was analysed at the mixing chamber in front of the ventilator inlet and inspiratory tube connected with the soda-lime carbon-dioxide absorber. Both NO concentrations showed a good correlation (r = 0.99). The actual NO concentration from the NO supply cylinder was 1154 ppm and NO2 concentration was 14 ppm. In mongrel dogs, after 20 minutes of NO inhalation (10-100 ppm), the blood methemoglobin level reached a peak value of 2.2% starting from the pre-inhalation level of 0%. To optimize the safety of the clinical application of NO, its concentration should be measured continuously with chemiluminescence technique.