Farmery A D, Hahn C E
Nuffield Department of Anaesthetics, University of Oxford, Radcliffe Infirmary, United Kingdom.
J Appl Physiol (1985). 2000 Aug;89(2):581-9. doi: 10.1152/jappl.2000.89.2.581.
Tidal ventilation gas-exchange models in respiratory physiology and medicine not only require solution of mass balance equations breath-by-breath but also may require within-breath measurements, which are instantaneous functions of time. This demands a degree of temporal resolution and fidelity of integration of gas flow and concentration signals that cannot be provided by most clinical gas analyzers because of their slow response times. We have characterized the step responses of the Datex Ultima (Datex Instrumentation, Helsinki, Finland) gas analyzer to oxygen, carbon dioxide, and nitrous oxide in terms of a Gompertz four-parameter sigmoidal function. By inversion of this function, we were able to reduce the rise times for all these gases almost fivefold, and, by its application to real on-line respiratory gas signals, it is possible to achieve a performance comparable to the fastest mass spectrometers. With the use of this technique, measurements required for non-steady-state and tidal gas-exchange models can be made easily and reliably in the clinical setting.
呼吸生理学和医学中的潮式通气气体交换模型不仅需要逐次求解质量平衡方程，还可能需要呼吸内测量，这些测量是时间的瞬时函数。这需要一定程度的时间分辨率以及气流和浓度信号积分的保真度，而大多数临床气体分析仪由于响应时间较慢无法提供这些。我们根据Gompertz四参数S形函数对Datex Ultima（芬兰赫尔辛基的Datex仪器公司）气体分析仪对氧气、二氧化碳和一氧化二氮的阶跃响应进行了表征。通过对该函数求逆，我们能够将所有这些气体的上升时间缩短近五倍，并且通过将其应用于实际的在线呼吸气体信号，可以实现与最快的质谱仪相当的性能。使用这种技术，可以在临床环境中轻松可靠地进行非稳态和潮式气体交换模型所需的测量。
