Correlation between exhaled nitric oxide and plasma nitrate levels in healthy individuals
Ashwani K. Chhibber, Stewart J. Lustik, Erin O’Hare, Jason Heckman, Denham S. Ward

Nitric oxide (NO), a free radical and a highly reactive gas, is formed by cleavage of the guanido group on arginine. NO plays an important role in many pathophysiological processes. There is a transient release of small amounts of NO by macrophages, from endothelium, platelets, the adrenal medulla and kidneys. Biological functions mediated by NO include vasodilatation, regulation of vascular tone, inhibition of platelet aggregation, mitochondrial respiration and neuronal transmission. NO has been determined in the exhaled gases in normal humans as well as in exhaled gases and in plasma in various disease states. It is less invasive and more convenient to estimate NO levels in exhaled gases than in blood samples. This study has been designed to compare and correlate NO levels in exhaled gases and plasma of healthy individuals. After approval by the Research Subjects Review Board at this institution, and written consent 50 adult subjects were studied. Plasma nitrate and Nitric oxide levels were measured. There was only a weak or no correlation between NO in exhaled gases and plasma nitrate levels in all subjects when plotted as a single group (R2 = 0.11 and P = 0.02) or when compared as separate genders, ( R2 = 0.26 and P = 0.01 for females, and R2 = 0.03 and P = 0.37 for males). Similarly no correlation was found in NO and nitrate levels in healthy subjects on no medications (R2 = 0.08 and P = 0.07). This study shows that the levels of nitric oxide in exhaled gases most likely represents local pulmonary physiological processes and may not represent systemic nitric oxide production in healthy individuals.

Keywords: Exhaled gases, nitric oxide, nitrate, ventilation

Applied Cardiopulmonary Pathophysiology 8: 37-40, 1999

Autorenanschrift:

Ashwani K. Chhibber, M.D.
University of Rochester Medical Center
Strong Memorial Hospital
Department of Anesthesiology
Box 604
601 Elmwood Avenue, Rochester
New York 14642
USA
Phone 716-275-2143
Fax 716-244-7271
E-mail: achhibber@ccmail.anes.rochester.edu