Computer-Controlled Eucapnic Voluntary Hyperpnea Challenge Method

Eucapnic voluntary hyperpnea (EVH) challenge is a well-established and sensitive method of determining the degree of bronchoconstriction at hospitals and clinics. This paper presents the development of a computer-controlled system for assessing exercise-induced bronchoconstriction (EIB) in humans including a computer graphic user interface (GUI) to control a low-pressure demand valve for better efficiency. GUI is designed to monitor the severity of acute lung airway narrowing using a MATLAB software and to present the measurement data into a simple user-friendly program consisting of patient information, EVH test analysis, and detection of exercise- induced asthma (EIA) and EIB. The proposed system is assessed using human subjects. Typical outputs from this system showed that for a female participant, a 20.25% and a 15.61% decrease from baseline in her forced expiratory volume in 1 s (FEVl) after 10 and 15 min of the challenge commencement, respectively. Her actual expiratory flow rate (45.833 L/m) and actual total volume of gas respired ( 275 L) were smaller than the target values. This system widens the usage of EVH challenge in medical areas, and the GUI may serve as a new clinical computer-aided diagnostic tool to help healthcare professionals noninvasively monitor the severity of asthma, EIA, and EIB.