Nitric oxide and nitrogen dioxide gradients in a test lung during high frequency oscillatory ventilation
Article
Totapally, B, Raszynski, A, Sussmane, J et al. (1998). Nitric oxide and nitrogen dioxide gradients in a test lung during high frequency oscillatory ventilation
. CRITICAL CARE MEDICINE, 26(1 SUPPL.), A118. 10.1097/00003246-199801001-00345
Totapally, B, Raszynski, A, Sussmane, J et al. (1998). Nitric oxide and nitrogen dioxide gradients in a test lung during high frequency oscillatory ventilation
. CRITICAL CARE MEDICINE, 26(1 SUPPL.), A118. 10.1097/00003246-199801001-00345
Introduction: Various factors influence nitric oxide (NO) and nitrogen dioxide (NO:) concentrations in the ventilator circuits. Alveolar concentrations of NO and NO: during high frequency oscillatory ventilation (HFOV) have not been systematically studied. We measured variations in NO and NO: concentrations in the ventilator circuit and the test lung's bellows during HFOV with various frequencies and amplitudes. Methods: A test lung (Biotech; model VT-2A) with pédiatrie configuration (compliance 0.01L/cmH:0 and resistance 20 cmH20/Umin) and an endotracheal tube (5.5 Fr cuffed was connected to a HFOV (Sensor Medics 3100A). The experiment was done with dry 100% oxygen. Bias flow of the ventilator and NO flow were blended before delivery into the proximal part of the inspiratory limb. NO and NO: concentrations were measured at four ports with an electrochemical analyzer (Pulmonox II). Port-1 was placed at the proximal part of the inspiratory limb, port-2 near patient-Y in the inspiratory limb, port-3 at the carina, and port-4 at the bellows of the test lung. Mean airway pressure (20 cm H20) and bias flow (20.5 L/min) were not altered during the experiment. Measurements were repeated at a frequency of 3 to 9 Hz and an amplitude (AP) of 35 to 50. Descriptive statistics and repeated measures ANOVA followed by Tukey-Kramer multiple comparison test were used to analyze the data. Results are reported as mean ±SEM. Results: A significant decrease in NO and increase in NO: concentration was found in the bellows of the test lung compared with the other three sites. The sum of NO + NO: concentration was similar in the proximal and distal port. N02 concentration at test lung's bellowsincreasedI with increasing inspiredI NO, figggiJarnitude. Pprt-1 Port-2 Port-3 Port-4 p-value NO(ppm) 86.1 ±0.30 82.0 ±0.30 81.1 ±0.30 70.0 ±0.20 < 0.001 NO2(ppm) 3.2 ±0.04 3.9 ±0.04 4.7 ±0.05 19.4 ±0.19 < 0.001 Conclusions: Gas sampling from the ventilator circuit during HFOV may not reflect their true alveolar concentrations of NO and NO:. Clinical implications of the present data in the test lung need to be confirmed in vivo.
