The Effects of Deep Inhalation on Maximal Expiratory Flow during Intensive Treatment of Spontaneous Asthmatic Episodes

Abstract

Asthmatic patients who came to hospital for treatment of severe attacks were assessed for level of obstruction and the effects of a deep inhalation (DI) on degree of obstruction at various stages of their treatment and after recovery over several days. The more severe the obstruction, the greater was the constrictor effect of a DI; as lung function improved with intensive treatment, including corticosteroids, the constrictor effect diminished. Thus, we believe the constrictor effects of a DI relate to the degree of inflammation in the obstructive process. These longitudinal data relating severity to the effects of a DI were nearly identical to previously published cross-sectional data in a group of patients with spontaneous asthma with widely different levels of lung function. It is possible that the response to a DI in a given asthmatic subject serves as a functional marker for the predominant mechanism for obstruction.

Airway smooth muscle dynamics: a common pathway of airway obstruction in asthma

“…At least three possible answers are presented in the literature. The first is provided by BURNS et al [17], PICHURKO et al [39], LIM and co-workers [40,41] and PLISS et al [42], which is based on the concept of relative hysteresis of airway versus lung and first developed by FROEB and MEAD [43]. They found, as did FISH et al [16], that in asthmatics, not only did deep inspiration fail to reverse spontaneous obstruction, it sometimes resulted in worsening of airway narrowing.…”

“…They found, as did FISH et al [16], that in asthmatics, not only did deep inspiration fail to reverse spontaneous obstruction, it sometimes resulted in worsening of airway narrowing. Furthermore, LIM and co-workers [40,41] showed that the degree of bronchoconstriction induced by deep inspiration was related to the severity of spontaneous obstruction at the time of testing. That is, asthmatic subjects with severe spontaneous airway obstruction responded to deep inspiration with a further decrement in maximal expiratory flow (on maximal as opposed to partial expiratory flow-volume curves).…”

“…These effects are illustrated in figure 1. Using the concept of relative parenchymal airway hysteresis, LIM and co-workers [40,41] postulated that during a spontaneous asthma attack, peripheral parenchymal hysteresis was much greater than that of the airways. An increase in lung pressure-volume hysteresis is characterised by greatly increased elastic recoil pressures during inflation and much lower recoil pressures during deflation at any given volume.…”

Asthma: where is it going?

“…Previous studies have reported bronchodilation and a bronchoprotective effect of deep inspiration on the airways, which was absent or diminished in asthma (26). Indeed, in asthmatics, deep inspiration fails to reverse spontaneous obstruction, and sometimes even results in worsening of airway narrowing (27)(28)(29). Furthermore, the degree of bronchoconstriction induced by deep inspiration is related to spontaneous obstruction severity (28,29).…”

“…Indeed, in asthmatics, deep inspiration fails to reverse spontaneous obstruction, and sometimes even results in worsening of airway narrowing (27)(28)(29). Furthermore, the degree of bronchoconstriction induced by deep inspiration is related to spontaneous obstruction severity (28,29).…”