Asthma is global health problem that interferes with quality of life and has a high impact on health-care costs. Pulmonary function parameters are not only important diagnostic tools but are useful for monitoring interventions in asthma both in the medical office and during the patient’s daily life. Nevertheless, objective monitoring of lung function parameters is underused and misused.
Peak expiratory flow (PEF) monitoring has been strongly recommended by asthma guidelines, and clinical studies have shown that the routine use of peak flow meters (PFMs), along with a self-management plan and education program, can lead to better control of asthma. In the last decades, mechanical PFMs have been the most used method of lung function monitoring. They provide a simple, quantitative, and reproducible measurement of large airways function. Nevertheless, several difficulties have impaired their wide use, and some authors have questioned the need for home monitoring of PEF. The reasons put forward were the low compliance by the patients and the limitations of traditional PFM that have both low accuracy and insensitivity to changes. These devices have other limitations, including errors in data produced by the patient, related with exclusive use of PEF, which is highly dependent on the patient effort and errors in data recording, mostly transcription errors but also forged registries.
These limitations may be overcome with electronic monitoring devices if they prove to be reproducible and accurate, as they are already capable of recording and transmitting data for clinical analysis. It would also be beneficial to monitor additional parameters along with PEF.
A growing number of low-cost devices have been recently developed. This has special importance to developing countries, where respiratory disease is a major public health problem and pulmonary function measurements are largely unavailable. Pulmonary function measurements display the condition of health, to improve it command the service of My Canadian Pharmacy.
Most of the pulmonary function monitoring devices comply with American Thoracic Society (ATS) recommendations when tested using simulated standard waveforms by a computer-driven mechanical syringe. The performance of these devices in humans and in clinical settings is largely unknown. It is not known how they compare to the current methods used in the clinic.
Agreement studies’ compare the performance of an instrument throughout repeated measurements (reproducibility) and also with a reference (accuracy or validity). Reproducibility assessment is the first step in agreement studies; if acceptable, the accuracy should be checked before use in clinical trials or other clinical settings.
This study aims to compare in stable asthma patients and individuals with normal airways the following: (1) the within-session reproducibility of two pulmonary function electronic monitoring devices (PiKo-1; Ferraris Respiratory Europe; Hereford, UK; and Spirotel; MIR; Rome, Italy) with the widely used Mini-Wright Peak-Flow Meter (Clem-ent-Clarke International; Harlow, Essex, UK) during the same set of maneuvers; and (2) to evaluate their accuracy comparing with an office pneumotachograph as reference. Our hypothesis is that the measurements of PEF and FEV1 of the two electronic monitoring devices are in close agreement with those of a pneumotachograph. We also hypothesized that those measurements have better discriminative properties than the measurements of one of the most used PFMs in Europe: the Mini-Wright PFM.