Effects of treadmill exercise versus Flutter® on respiratory flow and sputum properties in adults with cystic fibrosis: a randomised, controlled, cross-over trial

Abstract

BackgroundTreadmill exercise and airway clearance with the Flutter® device have previously been shown to improve mucus clearance mechanisms in people with cystic fibrosis (CF) but have not been compared. It is therefore not known if treadmill exercise is an adequate form of airway clearance that could replace established airway clearance techniques, such as the Flutter®. The aim of this study was to evaluate respiratory flow, sputum properties and subjective responses of treadmill exercise and Flutter® therapy, compared to resting breathing (control).MethodsTwenty-four adults with mild to severe CF lung disease (FEV1 28–86% predicted) completed a three-day randomised, controlled, cross-over study. Interventions consisted of 20 min of resting breathing (control), treadmill exercise at 60% of the participant’s peak oxygen consumption and Flutter® therapy. Respiratory flow was measured during the interventions. Sputum properties (solids content and mechanical impedance) and subjective responses (ease of expectoration and sense of chest congestion) were measured before, immediately after the interventions and after 20 min of recovery.ResultsTreadmill exercise and Flutter® resulted in similar significant increases in peak expiratory flow, but only Flutter® created an expiratory airflow bias (i.e. peak expiratory flow was at least 10% higher than peak inspiratory flow). Treadmill exercise and Flutter® therapy resulted in similar significant reductions in sputum mechanical impedance, but only treadmill exercise caused a transient increase in sputum hydration. Treadmill exercise improved ease of expectoration and Flutter® therapy improved subjective sense of chest congestion.ConclusionsA single bout of treadmill exercise and Flutter® therapy were equally effective in augmenting mucus clearance mechanisms in adults with CF. Only longer term studies, however, will determine if exercise alone is an adequate form of airway clearance therapy that could replace other airway clearance techniques.Trial registrationAustralian and New Zealand Clinical Trials Registry, Registration number #ACTRN12609000168257, Retrospectively registered (Date submitted to registry 26/2/2009, First participant enrolled 27/2/2009, Date registered 6/4/2009).Electronic supplementary materialThe online version of this article (doi:10.1186/s12890-016-0360-8) contains supplementary material, which is available to authorized users.

Acute effects of combined exercise and oscillatory positive expiratory pressure therapy on sputum properties and lung diffusing capacity in cystic fibrosis: a randomized, controlled, crossover trial

“…In the present study, we found no differences in sputum viscoelasticity between the two experimental conditions, thus rejecting our initial hypothesis. Two previous studies reported altered sputum viscoelasticity after an acute bout of treadmill exercise or Flutter® and treadmill exercise compared to resting breathing in adults with CF [6,11]. Treadmill but not cycling exercise reduced sputum viscoelasticity and trunk oscillations during treadmill running/walking have been postulated as a possible underlying mechanism [11].…”

“…Exhalation through the Flutter® causes oscillation of the steel ball and produces rhythmic variations in positive expiratory pressure of 10 to 25 cm H 2 O [28,29]. Flutter® therapy increases peak expiratory flow and creates an expiratory airflow bias in CF [6], initiating mucociliary clearance mechanisms.…”

“…With respect to Flutter®, our patients performed 6-10 breathing maneuvers during each of four cycles. Higher volumes of Flutter® therapy (6 cycles à 15 breaths) combined with huffing and coughing (forced expiration technique, FET) improved sputum viscoelasticity compared to resting breathing in adults with CF [6]. It is important to note that we deliberately did not follow existing CF physiotherapy recommendations [27] suggesting to individually determine the angle of the Flutter® along with the performance of forced expiratory maneuvers.…”

“…There are a number of different ACT's such as the active cycle of breathing technique, high-frequency chest wall oscillations, positive expiratory pressure (PEP) and oscillatory PEP. Oscillatory PEP with the Flutter® is equally effective compared to other ACT's [3] and has been shown to favorably alter respiratory flow [4], to increase sputum expectoration [5] and to reduce sputum viscoelasticity [6,7] in CF.…”

“…Exercise alone or in combination with chest physiotherapy improves airway clearance and sputum expectoration [6,8], but the exact mechanisms are not fully understood. Moreover, acute exercise is thought to facilitate mucociliary clearance by increased shear stress on airway epithelium and ciliary beat frequency as a result of an increased ventilation [9], improved water content of mucus [10] and increased trunk oscillations during weight bearing exercises such as walking or running [11].…”