Studies on the Intrapulmonary Mixture of Gases. I. Nitrogen Elimination From Blood and Body Tissues During High Oxygen Breathing

Heat-induced formation of nitrogen oxides in water

“…By extrapolating the rate constants of heat-induced NO − 2 generation at high temperatures to 37 • C, the rate constant of NO − 2 formation by the action of heat in homoiothermal organisms was estimated to be k 37 = 2 × 10 −7 M −1 s −1 at a rate of v 37 = 2.9 × 10 −15 M s −1 , with the mean intratissue oxygen concentration in mammals being 30 μM [46] and the nitrogen concentration in human blood being about 1% (∼490 μM) [47]. Thus, the daily heat-induced production of nitrite in a human body weighing 60 kg (the water content in the body of an adult is ∼60%) can reach 4.1 × 10 −7 g, which accounts for ∼0.08% of the content of nitrite (∼0.5 mg) a human receives daily with plant food [8].…”

Multiple-breath nitrogen washout techniques: including measurements with patients on ventilators

“…Unlike the He dilution method, the N 2 washout method may also wash out blood and tissue N 2 . However, unlike the original descriptions for adults, where a 7 min period of O 2 breathing was calculated to wash out 220 mL of tissue nitrogen (up to 10% of the FRC) [24,25], it has been suggested in newborn infants that the volume of tissue and blood N 2 washed out in a test is not more than 1% of the total [40]. That is, no significant amount of N 2 is washed out during a test which ends within 2-3 min at most, and at most will cause a 5% error [39,53].…”

“…The N 2 washout method for measuring lung volumes was developed into a clinical technique by DARLING and co-workers [23][24][25] in a series of papers published in 1940. The principle of the technique is that N 2 is washed out of the body by having the subject breathe 100% oxygen, starting the first inspiration of O 2 from FRC.…”

“…Tissue excretion rates of N 2 were measured in normal individuals, who had first hyperventilated to remove alveolar nitrogen stores [24], and were then applied in the above equation. DARLING and co-workers [24,25] assumed from their normal subjects that the total N 2 eliminated from the tissue stores during 7 min of O 2 breathing was approximately 220 mL, and made no adjustments for body weight in their subsequent patients. Estimated alveolar N 2 concentrations were measured at the beginning and end of expired gas collection during a forced exhalation.…”

André F. cournand: Father of clinical cardiopulmonary physiology

“…Accurate spirometric methods and mbrcathing as well as open circuit niethod of measuring residual air in the lung were developed in the Bellevue Lahmtory. and a quantitative description of lung washout of N, during high oxygen breathing was made with R. C. Darling in 1940(Darling e l ul., 1940. These tncthods were to lead to the clinical and physiologic classification of various forms of pulmonary disease.…”