Justice R E, Kripke B J, Hechtman H B
Crit Care Med. 1982 Dec;10(12):876-9. doi: 10.1097/00003246-198212000-00015.
Helium detectors utilizing thermal conductivity are sensitive to the presence of nitrous oxide (N2O) and oxygen (O2). Measurement of the level of these gases within the spirometer may be used to obtain the true helium concentration for use in the calculation of functional residual capacity (FRC). Linear relationships were obtained relating the change (delta) in reading of the helium meter by nitrous oxide and oxygen. The regression equations are: delta O2 = 0.027 (%O2) - 0.513; delta N2O = -0.276 (%N2O). Failure to correct the helium reading for N2O will overestimate lung volume; elevations of O2 above 21% will underestimate the lung volume.
利用热导率的氦气探测器对一氧化二氮（N₂O）和氧气（O₂）的存在敏感。测量肺活量计内这些气体的水平可用于获得用于计算功能残气量（FRC）的真实氦浓度。获得了一氧化二氮和氧气引起的氦气测量仪读数变化（δ）的线性关系。回归方程为：δO₂ = 0.027（%O₂） - 0.513；δN₂O = -0.276（%N₂O）。未对一氧化二氮进行氦读数校正会高估肺容积；氧气含量高于21%会低估肺容积。
