Measurement and monitoring of pulmonary function.

Several computerized systems that allow the collection of data for measurements of pulmonary function have been developed. Although many of these systems eliminate distorted and incomplete breaths from the analysis, there are still many possibilities for error secondary to the inexperience of the user or to patient-related factors. Training and experience with the use of these instruments is essential to obtain reliable results. A clear understanding of all the principles, the assumptions, and limitations affecting the measurements is also essential. The methodology underlying these systems is reviewed. In addition, the commercially available equipment needs to be standardized from an engineering point of view, to assure that the components used have the proper frequency response, that the signals are collected at proper rates, that calibration is simple and accurate, and that the analysis of the data is correct. Systems should be standardized against a lung model.