Determination of production of nitric oxide by lower airways of humans—theory

Hyde, Richard W., Edgar J. Geigel, Albert J. Olszowka, John A. Krasney, Robert E. Forster II, Mark J. Utell, and Mark W. Frampton.Determination of production of nitric oxide by the lower airways of humans—theory. J. Appl. Physiol.82(4): 1290–1296, 1997.—Exercise and inflammatory lung disorders such as asthma and acute lung injury increase exhaled nitric oxide (NO). This finding is interpreted as a rise in production of NO by the lungs (V˙no) but fails to take into account the diffusing capacity for NO (Dno) that carries NO into the pulmonary capillary blood. We have derived equations to measureV˙no from the following rates, which determine NO tension in the lungs (Pl) at any moment from1) production (V˙no);2) diffusion, where Dno(Pl) = rate of removal by lung capillary blood; and3) ventilation, whereV˙a(Pl)/(Pb− 47) = the rate of NO removal by alveolar ventilation (V˙a) and Pb is barometric pressure. During open-circuit breathing when Pl is not in equilibrium, d/dtPl[V l / (Pb − 47)] (where V l is volume ...