Safety of delivering nitric oxide through nitrous oxide path in anesthesia machine / 中华麻醉学杂志

ABSTRACT

To evaluate the feasibility of delivering NO through N_2O path in anesthesia machine,NO at 800 ppm was delivered through nitrous oxide path in anesthesia machine SIEMENS Ventilator 710 or NARKOMED 2B,to ventilate a test lung. The minute volume of ventilation (MV) was set from 2 to 6L/min, and NO concentration from 10 to 80 ppm. NO and NO_2 concentrations were measured by hemiluminescence and electro-chemical fuel cell technique. SIEMENS Ventilator 710Non-rebreathing model,its inspiratory limb was prolonged to 7 meters,the NO level was adjusted at 80ppm before passing through soda lime, NO and NO_2 samples were taken before absorber,after absorber, 1, 2,4 and 6 meter site in inspiratory limb. NARKOMED 2BOxygen flows were at the rates epual to the MV mentioned above, NO concentration was at 10,20,40,60 and 80 ppm,the inspiratory gas mixture was sampled immediately passing through absorber, NO_2 levels were less than 5.0ppm in all conditions listed above. With SIEMENS Ventilator 710, the highest level of NO_2 was 3.45 ppm before absorber and 2.43 ppm after absorber,with NARKOMED 2B,that was 3.6 ppm. As MV increased,NO_2 level before absorber decreased (P