A Correction Factor for Helium Absorption in Lung Volume Determinations

Nitrogen washout/washin, helium dilution and computed tomography in the assessment of end expiratory lung volume

“…Moreover, the helium dilution method is prone to other sources of error such as the helium concentration in the gas tank, which usually has a tolerance degree of about 5%, and possible diffusion of helium out of the balloon. In addition the possibility of helium uptake during EELV measurement has been discussed in the literature and is thought to be controversial [ 25 - 27 ]. Theoretical considerations show that the possible helium uptake is limited: the solubility coefficient of helium is 1.13 × 10 -5 ml/ml/mmHg [ 28 ] with a maximal body helium uptake of about 45 ml in 40 L body water and about 5 ml in well perfused body compartments.…”

Multiple breath helium dilution measurement of lung volumes in adults

“…Another investigator argued that the correction for helium absorption could be based only on very approximate estimates and chose to omit a correction [17]. In a study of the time-related disappearance of helium from the helium dilution system in two normal subjects, it was concluded that for a 7 min procedure, the correction in FRC should be 105 mL [24]. A graphical solution to the problem by extrapolation of the concentration-time curve to the beginning of the alteration in gas concentration was proposed [25] but subsequently rejected [14].…”