Determination of production of nitric oxide by the 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.
Departments of Medicine and Environmental Medicine, University of
Rochester School of Medicine and Dentistry, Rochester, NY 14642,
Department of Physiology, State University of New York School of
Medicine, Buffalo, NY 14214, and Department of Physiology, University
of Pennsylvania School of Medicine, Philadelphia, PA 19104
APStracts 3:0537A, 1996.
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 (O(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 measure (O(V,.)NO) from the following rates which
determine NO tension in the lungs (PL) at any moment from (1)
production: O(V,.)NO, (2) diffusion: where DNO(PL) = rate of removal
by lung capillary blood, and (3) ventilation: where O(V,.)A(PL)
divided by (PB-47) = the rate of NO removal by alveolar ventilation
(O(V,.)A). During open circuit breathing when PL is not in
equilibrium, d/dt PL[VL divided by (PB-47)] = O(V,.)NO -
DNO(PL)&O(V,.)A(PL) divided by (PB-47). When PL reaches a steady
state so that d/dt = 0, and O(V,.)A is eliminated by rebreathing or
breathholding: PL = O(V,.)NO divided by DNO. PL can be interpreted
as NO production per unit of DNO. The equation predicts that diseases
that diminish DNO but do not alter O(V,.)NO will increase expired NO
levels. These equations permit precise measurements of O(V,.)NO that
can be applied to determining factors controlling NO production by
the lungs.
Received 18 September 1996; accepted in final form 14 November
1996.
APS Manuscript Number A899-6.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996