Determination of dissolved N₂ in blood by gas chromatography and (a-A)N₂ difference

Abstract

By combining vacuum extraction in a Van Slyke chamber and separation of the extracted gases in a gas chromatograph, it is possible to determine N2 content of 1.5 ml of blood or other biological fluids in less than 10 min. The 95% confidence limits are 0.44% on either side of the mean of the triplicate analysis-or 2.4 mm Pn2 in arterial blood when breathing room air. Application of the method to the problem of arterial-alveolar N2 difference yielded the following data: 1) N2 solubility in whole blood at 37.3 C varied from 0.0125 to 0.0129; 2) N2 solubility in urine is inversely related to urine specific gravity, confirming Klocke and Rahn's data; 3) changes in arterial N2 content were reflected in arm superficial venous blood and urine N2 only after a considerable period of time, indicating that either of these will give an excellent indication of the mean Pn2 over a period of time; 4) there is no systematic difference between venous blood and urine Pn2; 5) the (a-A)N2 difference in nine normal subjects varied from 3.7 to 13.1 mm Hg. Note: (With the Technical Assistance of M. Passke) Submitted on July 24, 1962

Pulmonary Gas Trapping in Premature Infants

“…A periodic check of the accuracy of the method was carried out by determination of the Bunsen coefficient for N 2 in distilled water equilibrated with air at 37°. A value of 0.0127 ml N 2 /ml water/atm N 2 at 37°w as repeatedly obtained [8,21].…”

“…In each instance, the results from analysis of one representative curve are presented. The urinary alveolar nitrogen gradient (uAD N2 ) was determined in seven infants by the methods of Farhi, Edward, and Homma [8] as modified by Krauss and Auld [11]. A periodic check of the accuracy of the method was carried out by determination of the Bunsen coefficient for N 2 in distilled water equilibrated with air at 37°.…”

Regional lung function in patients with hepatic cirrhosis

“…Indeed, in all four subjects the regional functional residual capacity increased towards the lung bases, while in normal subjects it decreases progressively from lung top to bottom (36). The alveolar-arterial 02 differences were computed using the ideal alveolar air equation (32); the arterial-alveolar N2 differences were measured according to Farhi et al (33); the percentage shunt (% Q8/QT) was computed according to Berggren (34). 2406 Ruff et al…”

Endogenous production of carbon monoxide in normal and erythroblastotic newborn infants

“…The liberated blood gases were then extracted under vacuum using the modified microgasometer described by Natelson and Stellate (21) followed by injection into a gas chromatograph (Perkin-Elmer 154L). The method of gas injection was modified from Farhi, Edwards, and Homma (22) where the connecting tube leading from the upper two-way stopcock of the microgasometer is connected to two limbs of a four-arm, four-way stopcock. Blood samples of 0.24 ml were drawn up followed by reagents in the following order: 0.025 ml of 1 N lactic acid, 0.024 ml of 10% potassium ferricyanide, 0.1 ml of a solution containing two parts 30% Triton X-100 in saline and one part caprylic alcohol.…”

“…Interest in neonatal hemoglobin turnover has led previous investigators (7)(8)(9)(10) Received for publication 2 January 1970 and in revised form 22 June 1970.…”