nitric oxide + carbon monoxide + helium

Nitric oxide + carbon monoxide + helium is a diagnostic gas mixture utilized in pulmonary function testing (PFT) to evaluate the lung's diffusing capacity. This specific combination is employed in both single-breath and steady-state measurement techniques to determine the diffusing capacity for nitric oxide (DLNO) and carbon monoxide (DLCO). Nitric oxide and carbon monoxide act as tracer gases that diffuse from the alveoli into the pulmonary capillaries where they bind to hemoglobin. Because NO has a significantly higher affinity for hemoglobin than CO, DLNO is less dependent on pulmonary capillary blood volume and more reflective of the alveolar-capillary membrane's conductance. Helium is included in the mixture as an inert tracer gas to measure alveolar volume (VA) through the gas dilution method. This multi-gas diagnostic tool is particularly valuable for characterizing the underlying pathophysiology of gas exchange efficiency in conditions such as interstitial lung disease, pulmonary hypertension, and chronic obstructive pulmonary disease.

Other names

DLNO/DLCO/VA gas mixtureNitric oxide-carbon monoxide-helium mixturePulmonary diffusing capacity test gas