Use of noseclips in pulmonary function tests.

Spirometry was performed on 136 male industrial workers experienced in undergoing pulmonary function testing for the purpose of studying the effects of the use of noseclips on forced vital capacity (FVC) maneuvers. A cross-over design was employed with each subject serving as his own reference. Forced expiratory volume in 1 second (FEV1) and FVC measurements were recorded adhering closely to the guidelines set down by the American Thoracic Society. Assuming that a 30-ml difference in FVC and FEV1 is not important, we conclude that these measurements are not significantly affected by the use of noseclips. However, trial order was found to affect the outcome. The FVC and FEV1 values on the first trial were consistently lower than those on the second regardless of noseclip use. Many subjects experienced discomfort from noseclips and their use is not recommended for routine purposes.

A new method for measuring the pneumotachometer characteristics using a syringe.

A new method for determining the nonlinear characteristics of pneumotachometers was developed. This method consists of a computer algorithm analyzing unsteady flows generated by a syringe. We removed the possible influence of the frequency characteristics of the measuring system by inserting an acoustic low pass filter in the path of gas flow. Two types of Fleisch pneumotachometers were tested. For a given volume of 3 l, the error of measured volume is 12.5% in uncorrected series and 0.2% in the corrected.

Use of the peak flow meter in office practice.

The peak expiratory flow rate (PEFR) may be measured in the office or at home with an inexpensive, hand-held meter. Measurement of the PEFR provides a rapid, objective means of diagnosing and monitoring asthma. Use of the peak flow meter permits early detection of deteriorating function, allowing timely institution of additional therapeutic measures and preventing the need for hospital admission. During an acute attack of asthma, the PEFR aids in determining whether admission is necessary.

An intraindividual comparison of standard and mini-Wright scores.

The relationship between peak expiratory flow rate scores recorded with the standard Wright meter and those recorded with the mini-Wright meter was determined by correlating these scores on an intraindividual basis. These correlations were compared with correlations between pairs of standard scores. The latter were computed so as to provide an estimate of peak expiratory flow rate variability unrelated to recording apparatus. The results showed that pairs of standard Wright scores were more highly related to one another than were pairs of standard and mini-Wright scores. From these observations it was concluded that standard and mini-Wright scores are not equivalent and therefore may not confidently be interchanged.

Report of a newly redesigned Peak Flow Whistle.

A redesigned Peak Flow Whistle is described. It was evaluated and compared to the Wright Peak Flow Meter (WPFM) and the Vitalograph Pulmonary Monitor (VPM) using a laboratory flow system. These devices were evaluated for accuracy at steady flows, resistance characteristics, measurement of drift and dynamic accuracy. All devices tested correlated to a significant degree for accuracy at steady flows. The resistance of the WPFM and VPM increased with higher flows, whereas the Cardboard Peak Flow Whistle (CPFW) decreased. After pulsing the CPFW did not show any drift in calibration. The dynamic accuracy of the CPFW was excellent. Thus the accuracy of the CPFW and its lower cost makes it a practical device for measuring peak flows.

The Mini-Wright Peak Flow Meter for evaluating airway obstruction in a family practice.

This work reports an investigation of the usefulness of the Mini-Wright Peak Flow Meter in a family practice. The Mini-Wright Peak Flow Meter, an economical and simple tool for measuring peak expiratory flow rate, was developed in Great Britain but has found little clinical application in the United States. Its employment in quantifying airway obstruction and accurately reflecting changing patterns of obstruction over time is described. Recurrent patterns of airway obstruction in asthmatic patients are discussed. These patterns are used to individualize drug treatment regimens. The Mini-Wright Peak Flow Meter is portable and can easily be used in an office setting or lent to patients for home use. Some patients may benefit by purchasing the meter themselves and self-adjusting the time and dose of their medication based on objective measurements of airway obstruction.