Ib. Perillo et al., Chemiluminescent measurements of nitric oxide pulmonary diffusing capacityand alveolar production in humans, J APP PHYSL, 91(5), 2001, pp. 1931-1940
Measurements of nitric oxide (NO) pulmonary diffusing capacity (DLNO) multi
plied by alveolar NO partial pressure (PA(NO)) provide values for alveolar
NO production ((V) over dotA(NO)). We evaluated applying a rapidly respondi
ng chemiluminescent NO analyzer to measure DLNO during a single, constant e
xhalation (Dex(NO)) or by rebreathing (Drb(NO)). With the use of an initial
inspiration of 5-10 parts/ million of NO with a correction for the measure
d NO back pressure, DexNO in nine healthy subjects equaled 125 +/- 29 (SD)
ml.min(-1).mmHg(-1) and Drb(NO) equaled 122 +/- 26 ml.min(-1).mmHg(-1). The
se values were 4.7 +/- 0.6 and 4.6 +/- 0.6 times greater, respectively, tha
n the subject's single-breath carbon monoxide diffusing capacity (Dsb(CO)).
Coefficients of variation were similar to previously reported breath-holdi
ng, single-breath measurements of DsbCO. PANO measured in seven of the subj
ects equaled 1.8 +/- 0.7 mmHg x 10(-6) and resulted in (V) over dot A(NO) o
f 0.21 +/- 0.06 mul/min using Dex(NO) and 0.20 +/- 0.6 mul/min with Drb(NO)
. Dex(NO) remained constant at end-expiratory oxygen tensions varied from 4
2 to 682 Torr. Decreases in lung volume resulted in falls of Dex(NO) and Dr
b(NO) similar to the reported effect of volume changes on Dsb(CO). These da
ta show that rapidly responding chemiluminescent NO analyzers provide repro
ducible measurements of DLNO using single exhalations or rebreathing suitab
le for measuring (V) over dot A(NO).