Exercise‐induced bronchospasm in children: Comparison of FEV₁ and FEF_25–75% responses

Abstract

The response of asthmatic children to exercise has usually been evaluated by forced expiratory volume in 1 sec (FEV(1)). We reasoned that other respiratory indexes derived from the forced vital capacity maneuver such as forced expiratory flow between 25-75% of vital capacity (FEF(25-75%)) would add significant information in the evaluation of the relationship between asthma severity and response to exercise. We studied 164 children with intermittent (n = 63), mild persistent (n = 30), moderate persistent (n = 40), and severe persistent asthma (n = 31). Subjects exercised for 6 min on a cycle ergometer at 80% of their maximum heart rate, and spirometry was performed before and 5, 10, and 20 min after exercise. There was good correlation between changes in FEV(1) and FEF(25-75%) after exercise (r = 0.60, P < 0.001 for intermittent asthma and r = 0.80, P < 0.001 for severe persistent asthma). The presence of a fall in both FEV(1) (>/=10%) and in FEF(25-75%) (>/=26%) when compared to a decrease in only one of these two indexes was significantly greater in children with more severe asthma (60.0% for intermittent asthma and 94.4% for severe persistent asthma, P = 0.022). FEF(25-75%) can decrease in response to exercise without changes in FEV(1), mainly in children with mild asthma. In the evaluation of the response to exercise in children with different asthma severities, more than one maximum expiratory flow-volume parameter should be used.

The FEF25–75and its Decline as a Predictor of Methacholine Responsiveness in Children

“…Fonseca-Guedes was able to show that FEF 25-75 could decrease in response to exercise without changes in FEV 1 , mainly in children with mild asthma. That study demonstrated good correlation between the changes in FEV 1 and FEF 25-75 after exercise and also found that the decrease in these parameters increased as the severity of asthma increased (24). This suggests that using more than one flow volume parameter may be helpful in detecting hyperresponsiveness of the airways.…”

Methacholine and adenosine 5'-monophosphate challenges in children with post-infectious bronchiolitis obliterans

“…However, FEF25-75% is more variable and less reproducible than FEV1. In addition, as full vital capacity may not be delivered in a forced expiratory manoeuvre in the presence of severe airway obstruction, FEF25-75% may underestimate the degree of airway obstruction [28]. Thus, the use of this index in assessing AHR may be misleading.…”

Small-airways dysfunction associates with respiratory symptoms and clinical features of asthma: A systematic review

“…Interestingly, a few studies have shown that small-airways dysfunction is not only a feature of severe asthma but can also be present in patients with mild asthma who have a low level of symptoms and FEV 1 values in the normal range. 15,47,55,61,68 This indicates that the possibility of small-airways dysfunction should be considered in the complete spectrum of asthma severity. The latter might be of clinical importance because a better small-airways response to treatment with extrafine-particle ICSs or montelukast is accompanied by better asthma control.…”

“…This systematic review demonstrates that small-airways dysfunction is associated with clinical features of asthma: worse control of asthma, 15,16,20,21 higher numbers of exacerbations, 21,27,33 nocturnal asthma, 40,41,44 more severe BHR, 55,56,59,60 exercise-induced asthma, 61,64,[67][68][69][70][71] and the late-phase allergic response (Table II). * It is important to mention that the data for this review are limited because most of the studies are small and not primarily designed to answer our research question.…”