Does the inhalation device affect the bronchodilatory dose response curve of salbutamol in asthma and chronic obstructive pulmonary disease patients?

Does device matter for inhaled therapies in advanced chronic obstructive pulmonary disease (COPD)? A comparative trial of two devices

Objective

COPD patients have challenges for effective use of inhalers due to advanced age, fixed airflow obstruction and comorbid medical conditions. Published clinical trials investigate drug efficacy but rarely consider the inhaler device. This trial investigates device efficacy, comparing clinical outcomes for the same medication via two different devices. Our intention was to communicate the results and to critically appraise the study protocol to inform planning of future device comparison research. Subjects with spirometry confirming at least moderate COPD were randomly assigned to inhaler sequence; starting with Accuhaler or metered dose inhaler and spacer (MDI/s). After baseline testing, subjects were assigned to fluticasone propionate/salmeterol xinafoate (SFC) 500/50 mcg twice daily via the first device for 6 weeks’ duration, then changed to the alternate device for the following 6 weeks. Subjects were reassessed in terms of health-related quality of life (HRQL), exercise endurance and lung function after each exposure period.

Results

The recruitment target was not achieved due to unanticipated developments within the pharmaceutical industry, potentially compromising the study’s power. Study outcomes did not differ significantly according to the allocated inhaler device even after adjusting for baseline lung function or inhaler technique. Recommendations for future device comparison protocols are offered.

Trial registration Australia and New Zealand Clinical Trials Registry, Current Controlled Trials ACTRN12618000075280, date of registration: 18.01.2018. Retrospectively registered

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4123-5) contains supplementary material, which is available to authorized users.

Role of maximal inspiratory presure in the evaluetion of respiratory muscle strength in asthmatics - Systematic review

Asthma is a chronic illness of the airways that can reduce respiratory muscle strength due to the resulting hyperinflation or treatment with corticosteroids. One of the ways to evaluate this respiratory muscular weakness is the Maximal Inspiratory Pressure (PImax).

METHODS

A systematic review of the databases PUBMED/MEDLINE, LILACS and SCIELO was carried through, using the key words: Asthma, respiratory muscle and muscle strength.

RESULTS

Fifty were found and six articles that evaluated the PImax in asthmatics, from these, thirty were excluded, making a total of twenty six articles.

FINAL CONSIDERATIONS

Through the present revision we show the effectiveness of PImax in evaluating respiratory muscle strength in asthmatics. More studies are needed, however, fot better understanding of the asthmatic individual. Rev Port Pneumol 2010; XVI (3): 463-470.

Association of airway pentosidine levels with bronchodilator response mediated by salbutamol administration in asthmatic patients

BACKGROUND

Recently, increased levels of pentosidine, an intermolecular cross-linking type of advanced glycation end products, are observed in the airways of asthmatic patients. This study was designed to determine whether differences in bronchodilator response among individuals with asthma are attributable to pentosidine levels in their airways.

METHODS

Fifty-six asthmatic patients (21 with airway obstruction, 35 without airway obstruction) and 10 normal controls were included in this study. For asthmatic patients, we evaluated the spontaneous reversibility of airway obstruction or the reversibility that can be obtained after methacholine provocation. And we also measured pentosidine levels and percentage of sputum eosinophils in induced sputum, and exhaled nitric oxide (NO) levels.

RESULTS

The pentosidine levels did not significantly differ between the two asthmatic subgroups with and without airway obstruction. In asthmatic patients without airway obstruction, airway hyperresponsiveness to methacholine (PC20 methacholine) was significantly correlated with sputum eosinophils and exhaled NO levels. In contrast, PC20 methacholine was not significantly correlated with pentosidine levels. In asthmatic patients with or without airway obstruction, bronchodilator response was not significantly correlated with sputum eosinophils and exhaled NO levels. However, bronchodilator response was closely correlated with pentosidine levels (asthmatics without airway obstruction: r = -0.54, p = 0.002; asthmatics with airway obstruction: r = -0.48, p = 0.03).

CONCLUSIONS

Our results showed that pentosidine might be a potential biomarker reflecting the reduced bronchodilator response in asthma. This study will provide new insights into the mechanisms underlying persistent airway obstruction.

Aerosol drug delivery: developments in device design and clinical use

Aerosolised drugs are prescribed for use in a range of inhaler devices and systems. Delivering drugs by inhalation requires a formulation that can be successfully aerosolised and a delivery system that produces a useful aerosol of the drug; the particles or droplets need to be of sufficient size and mass to be carried to the distal lung or deposited on proximal airways to give rise to a therapeutic effect. Patients and caregivers must use and maintain these aerosol drug delivery devices correctly. In recent years, several technical innovations have led to aerosol drug delivery devices with efficient drug delivery and with novel features that take into account factors such as dose tracking, portability, materials of manufacture, breath actuation, the interface with the patient, combination therapies, and systemic delivery. These changes have improved performance in all four categories of devices: metered dose inhalers, spacers and holding chambers, dry powder inhalers, and nebulisers. Additionally, several therapies usually given by injection are now prescribed as aerosols for use in a range of drug delivery devices. In this Review, we discuss recent developments in the design and clinical use of aerosol devices over the past 10-15 years with an emphasis on the treatment of respiratory disorders.

Salbutamol relative lung and systemic bioavailability of large and small spacers

Differences between the size and shape of spacers may affect the emitted dose and provide different effects when interchanged during routine use. Using a urinary pharmacokinetic method we have measured the relative lung and systemic bioavailability from urinary salbutamol excretion 30 min (USAL0.5) and 24 h (USAL24), respectively, after the inhalation of two 100-μg doses from a Ventolin Evohaler when used alone (MDI) and when attached to the Volumatic (VOL) or the Aerochamber Plus (AERO) spacers. The in-vitro properties of the emitted dose were determined. The mean (s.d.) USAL0.5 values following MDI, VOL and AERO (n = 13 volunteers) were 5.7 (1.9), 16.4 (8.2) and 14.8 (7.4) μg, respectively. VOL and AERO were significantly greater (P < 0.001 and < 0.01, respectively) than MDI. Comparison of VOL and AERO was similar with a mean ratio (90% confidence interval) of 108.2 (84.5, 138.6)%. USAL24 values between the three inhalation methods were similar. The values for the mean (s.d.) fine particle dose of two 100-μg doses emitted from MDI, VOL and AERO were 83.0 (6.8), 83.6 (4.6) and 73.6 (2.9) μg and the mass median aerodynamic diameters were 2.7 (0.03), 2.8 (0.07) and 2.9 (0.10) μm, respectively. The results showed that during routine use the Volumatic and the Aerochamber Plus spacers should provide similar lung and systemic delivery when attached to a Ventolin Evohaler.

Targeting drugs to the airways: The role of spacer devices

AIM

Spacer devices are inhalation aids of varying dimension and complexity, specifically designed to overcome problems with the use of pressurised metered dose inhalers (pMDIs). The aim of this review is to examine the current understanding about these inhalation devices and discuss their advantages and disadvantages.

METHODS

The pertinent literature concerning the characteristics and effects of spacers on delivery and lung deposition of inhaled medications, as well as their clinical efficacy in patients with reversible airway obstruction, is examined.

RESULTS

Spacers minimise problems of poor inhalation technique with pMDI, reduce oropharyngeal deposition and increase lung deposition. Spacers improve the clinical effect of inhaled medications, especially in patients unable to use a pMDI properly. Compared to both pMDIs and dry-powder inhalers, spacers may increase the response to beta-adrenergic bronchodilators, even in patients with correct inhalation technique. A pMDI plus spacer has proven to be viable lower cost alternative to the use of a nebuliser for delivering large bronchodilator doses in patients with severe acute asthma or chronic obstructive pulmonary disease. The use of large-volume spacers is recommended for delivering high doses of inhaled corticosteroids, and may permit a lower maintenance dose to be used.

CONCLUSION

pMDIs may be routinely fitted with a spacer, especially in situations where correct pMDI use is unlikely.

Airway distensibility in adults with asthma and healthy adults, measured by forced oscillation technique

RATIONALE

Reduced airway distensibility in subjects with asthma compared with control subjects may be related to differences in lung elastic recoil and bronchomotor tone.

OBJECTIVES

To examine the contribution of lung elastic recoil and bronchomotor tone to airway distensibility.

METHODS

We compared airway distensibility in 18 subjects with asthma with 19 control subjects before and after bronchodilator administration and, in a subgroup of 7 subjects with asthma and 8 control subjects, correlated distensibility with pressure-volume parameters.

MEASUREMENTS AND MAIN RESULTS

Distensibility was measured, using the forced oscillation technique, as the linear slope of conductance versus volume between total lung capacity (TLC) and 75% TLC and between 75% TLC and FRC. Transpulmonary pressure was recorded concurrently with distensibility, using an esophageal balloon. Pressure-conductance data were described using linear regressions and pressure-volume data were described using exponential equations. Subjects with asthma had lower baseline FEV1 (p=0.0003) and conductance (p=0.002) than did control subjects. Distensibility above 75% TLC was less in subjects with asthma than in control subjects (p<0.0001), but there was no difference below 75% TLC. Bronchodilator administration did not alter distensibility despite increases in FEV1 (p=0.0002) and conductance (p<0.0001) in subjects with asthma, and conductance (p=0.0004) in control subjects. After bronchodilator administration, subjects with asthma had reduced lung elastic recoil compared with control subjects (p=0.03) and a reduced pressure-conductance slope (p=0.01), but there were no correlations between pressure-volume characteristics and airway distensibility.

CONCLUSIONS

Airway distensibility measured by forced oscillation technique is reduced in subjects with asthma compared with subjects without asthma, is not related to lung elastic recoil, and is unchanged by bronchodilator administration. Airway wall remodeling remains the most likely cause of reduced airway distensibility in asthma.

Clinical and functional responses to salbutamol inhaled via different devices in asthmatic patients with induced bronchoconstriction

AIMS

This study aimed at evaluating changes in airway patency, lung volumes and perception of breathing discomfort intensity following salbutamol administration via the Diskus dry-powder inhaler (DPI) or a pressurized metered-dose inhaler with the Volumatic valved holding chamber (pMDI + Volumatic) in asthmatic patients with methacholine-induced bronchoconstriction.

METHODS

On six different study days, 18 patients inhaled methacholine until forced expiratory volume in 1 s (FEV(1)) decreased by approximately 35% of baseline. Following placebo, 200 and 400 microg of salbutamol through the pMDI + Volumatic or the Diskus, changes in FEV(1), volume-adjusted mean forced expiratory flow from 25 to 75% of the forced vital capacity (isoFEF(25-75)), lung volumes and breathing discomfort intensity, assessed by visual analogue scale (VAS) score, were repeatedly measured over a 60-min observation period.

RESULTS

Induced bronchoconstriction was accompanied by obvious reductions in lung volumes and increases in VAS score. After salbutamol administration, FEV(1) and VAS score changes were similar in all experimental conditions. However, following 400 microg salbutamol via pMDI + Volumatic, isoFEF(25-75) values increased up to 4.48 l s(-1) (95% confidence interval 4.06, 4.90), a significantly (P < 0.01) higher value than those attained in all other experimental conditions. Independently of the salbutamol dose, lung volumes rose to significantly (P < 0.01) higher levels in pMDI + Volumatic than in Diskus trials. The low salbutamol dose via the pMDI + Volumatic and the high dose via the DPI increased isoFEF(25-75) and lung volumes to similar extents.

CONCLUSIONS

Salbutamol via the pMDI + Volumatic provides greater isoFEF(25-75) and lung volume increases in asthmatic patients with induced bronchoconstriction; salbutamol-induced changes in VAS scores poorly reflect those in small airway patency. The lack of differences in FEV(1) increases observed after 200 and 400 microg salbutamol may reflect attainment of the flat portion of the dose-response curve using either device.