Assessing and accessing the small airways; implications for asthma management

Abstract

a b s t r a c tDespite the wealth of experience in the management of asthma, the disease remains inadequately controlled in some patients, who face long-term respiratory impairment and disability. The disease has been characterised as an inflammatory condition affecting first the larger airways and eventually the smaller airways, but there is evidence that peripheral airway involvement defines a particular and more severe phenotype of asthma. For this reason, assessing functional and biological parameters reflective of small airways involvement is important prognostically. No assessment method is universally and directly representative of peripheral airway function, but the traditional spirometric tests, including vital capacity, residual volume and forced vital capacity, are somewhat correlated with this function; useful methods for further assessment include the single-breath nitrogen wash-out test, impulse oscillometry, nitrous oxide and exhaled breath concentrate measurements, as well as computed tomography to reflect air trapping and response to treatment. Formulation advancements have made for easier treatment access to the smaller airways, with the new extrafine formulations resulting in better asthma control compared with non-extrafine formulations.

Why use long acting bronchodilators in chronic obstructive lung diseases? An extensive review on formoterol and salmeterol

“…This suggests differences between these drugs in coupling/ activation of β 2 -adrenoceptor and/or signal transduction from this receptor. The possible explanation of no improvement of salmeterol responses by budesonide is a greater involvement of the inhibitory Gi protein signalling from the receptor stimulated with salmeterol than with formoterol and earlier described insensitivity of Gi protein to glucocorticosteroid treatment [27]. From the clinical perspective, these results suggest that the combined treatment with budesonide/formoterol could guarantee an efficient bronchodilation during periods with increased inflammation such as during asthma exacerbations, whereas effects of combination treatment with a glucocorticosteroid and salmeterol may be less efficient during inflammation.…”

Lung penetration and patient adherence considerations in the management of asthma: role of extra fine formulations

“…Accessing and treating the distal part of the lung has recently been reviewed by Scichilone et al24 To date, there are three single-agent extra-fine formulations on the market (beclomethasone, ciclesonide, formoterol), and only one fixed-combination product is available (beclomethasone-formoterol), although a Phase II randomized controlled trial of a fixed combination of ciclesonide-formoterol formulated as a powder has recently been published 25. The fine particle fraction of this new powder formulation is approximately 50% smaller than that in the ciclesonide hydrofluoroalkane MDI 25.…”

Small Airways Dysfunction in Asthma: Evaluation and Management to Improve Asthma Control

“…There have been many reviews published recently in the last few years on small airways dysfunction and its importance in respiratory disease, particularly in asthma, as interest in this topic has be rekindled by advances in measurement techniques of, and therapeutic delivery to, the peripheral lung regions 1,2,3,4. This review attempts to approach the topic in a different manner.…”