Enhancing Inhalation Drug Delivery: A Comparative Study and Design Optimization of a Novel Valved Holding Chamber

This paper presents an innovative approach to the design optimization of valved holding chambers (VHCs), crucial devices for aerosol drug delivery. We present the design of an optimal cylindrical VHC body and introduce a novel valve based on particle impaction theory. The research combines computational simulations and physical experiments to assess the performance of various VHCs, with a special focus on the deposition patterns of medication particles within these devices. The methodology incorporates both experimental and simulation approaches to validate the reliability of the simulation. Emphasis is placed on the deposition patterns observed on the VHC walls and the classification of fine and large particles for salbutamol sulfate particles. The study reveals the superior efficacy of our valve design in separating particles compared to commercially available VHCs. In standard conditions, our valve design allows over 95% of particles under 7 μm to pass through while effectively filtering those larger than 8 μm. The optimized body design accomplishes a 60% particle mass flow fraction at the outlet and an average particle size reduction of 58.5%. When compared numerically in terms of size reduction, the optimal design outperforms the two commercially available VHCs selected. This study provides valuable insights into the optimization of VHC design, offering significant potential for improved aerosol drug delivery. Our findings demonstrate a new path forward for future studies, aiming to further optimize the design and performance of VHCs for enhanced pulmonary drug delivery.

Dynamic Analysis of Aerosol Release from a Pressurized Metered Dose Inhaler Combined with a Valved Holding Chamber Using Simplified Laser Photometry

Background: A pressurized metered dose inhaler combined with a valved holding chamber (pMDI+VHC) is used to prevent upper airway complications and improve the efficiency of inhaled drug delivery; however, the aerodynamic behavior of the released particles has not been well investigated. This study aimed at clarifying the particle release profiles of a VHC using simplified laser photometry. Methods: An inhalation simulator comprised a computer-controlled pump and a valve system that withdrew aerosol from a pMDI+VHC using a jump-up flow profile. A red laser illuminated the particles leaving VHC and evaluated the intensity of the light reflected by the released particles. Results: The data suggested that the output (OPT) from the laser reflection system represented particle concentration rather than particle mass, and the latter was calculated as OPT × instantaneous withdrawn flow (WF). Summation of OPT hyperbolically decreased with flow increment, whereas summation of OPT × instantaneous flow was not influenced by WF strength. Particle release trajectories consisted of three phases, namely increment with a parabolic curve, flat, and decrement with exponential decay phases. The flat phase appeared exclusively at low-flow withdrawal. These particle release profiles suggest the importance of early phase inhalation. The hyperbolic relationship between WF and particle release time revealed the minimal required withdrawal time at an individual withdrawal strength. Conclusions: The particle release mass was calculated as laser photometric output × instantaneous flow. Simulation of the released particles suggested the importance of early phase inhalation and predicted the minimally required withdrawal time from a pMDI+VHC.

[Inhalation therapy in dogs and cats with chronic lower airway disease - a literature review]

Chronic respiratory diseases are prevalent medical conditions in dogs and cats requiring lifelong treatment. Mainstay of therapy for chronic inflammatory respiratory diseases are glucocorticoids. Concurrent treatment with bronchodilators may be necessary to control clinical signs sufficiently. Due to the successful use in people as well as subsequent reduction of adverse effects of long-term glucocorticoid therapy, inhalative therapy has become increasingly important in veterinary medicine as well. Primarily spacers or valved holding chambers, in combination with metered dose inhalers, are used in dogs and cats. The technical properties of these devices, as well as their use and maintenance will be described in the following article. Furthermore, the existing literature regarding efficacy of inhalative medications for therapy of chronic inflammatory airway diseases in dogs and cats will be summarized.

Effect of different accessory devices on the dose delivered from pressurised metred-dose inhalers

INTRODUCTIONS

Improved aerosol delivery of bronchodilators to chronic obstructive pulmonary disease (COPD) subjects is a cornerstone in the treatment approach. Drug delivery and response are improved with the use of accessory devices [spacers and valved holding chambers (VHCs)] with metred-dose inhalers (pMDIs). However, different accessory devices are available in the market with different properties that could affect aerosol delivery. Thus, this study aimed to assess the relative lung deposition and systemic bioavailability and compare bronchodilator response of salbutamol delivered using different accessory devices attached to pMDIs.

METHODS

Twelve healthy subjects and twelve COPD subjects inhaled 300 μg salbutamol (3 pMDI puffs) using five different accessory devices with either masks or mouthpieces (Able, Aerochamber plus flow Vu, Dolphin chamber, Tipshaler spacer, and modified Drink bottle spacer). Urine samples were collected thirty minutes post-dosing and cumulatively for the next twenty-four hours, to determine and compare the relative lung deposition [0-0.5 hour excretion of urinary salbutamol (USAL0.5)] and systemic bioavailability [0.5-24 hours excretion of urinary salbutamol (USAL24)] of salbutamol from the selected accessory devices. Also, the difference between pre and post-inhalation forced expiratory volume in one second (ΔFEV₁ %) of predicted was determined for each accessory device.

RESULTS

Urinary excretion of salbutamol (both USAL0.5 and USAL24 samples) in COPD subjects was significantly (P < .05) lower than in healthy subjects for all accessory devices. USAL0.5 and USAL24 in non-antistatic spacers (modified Drink bottle spacer and Dolphin chamber spacers) were significantly lower (P < .05) than that for antistatic spacers (Aerochamber plus flow Vu, Able and Tips-haler). No significant difference in USAL0.5 and USAL24 was observed between facemasks and mouthpieces. There was a significant difference (P < .05) in ΔFEV₁ % of predicted values between COPD subjects and healthy subjects. However, within the COPD group and the healthy group there was no significant difference in ΔFEV₁ % of predicted values between all accessory devices or between with mouthpiece or with a mask.

CONCLUSIONS

COPD subjects had lower aerosol delivered compared with healthy subjects. Anti-static accessory devices delivered a higher amount of aerosol compared with non-antistatic accessory devices. Even though the presence of a significant difference in aerosol delivery between non-antistatic and antistatic accessory devices no significant difference was found in the ΔFEV₁ % between all accessory devices.

Effect of a spacer on total systemic and lung bioavailability in healthy volunteers and in vitro performance of the Symbicort® (budesonide/formoterol) pressurized metered dose inhaler

INTRODUCTION

Many patients with chronic obstructive pulmonary disease or asthma experience difficulties in coordinating inhalation with pressurized metered-dose inhaler (pMDI) actuation. The use of a spacer device can improve drug delivery in these patients. The aim of this study was to establish the relative bioavailability of single doses of Symbicort^® (budesonide/formoterol) pMDI 160/4.5 μg/actuation (2 actuations) used with and without a spacer device. In addition, an in vitro study was conducted to characterize performance of the inhaler when used in conjunction with a spacer device.

METHODS

A Phase I, randomized, open-label, single-dose, single-center, crossover study in 50 healthy volunteers (NCT02934607) assessed the relative bioavailability of single-dose Symbicort^® pMDI 160/4.5 μg/actuation (2 actuations) with and without a spacer (AeroChamber Plus^® Flow-Vu^®). Inhaled doses were administered without or with activated charcoal (taken orally) to estimate total systemic exposure and exposure through the lung, respectively. The in vitro study characterized the effect of the spacer with respect to delivered dose, fine particle dose, and dose during simulated breathing of budesonide and formoterol.

RESULTS

In terms of total systemic exposure, use of the spacer increased the relative bioavailability determined by AUC_(0-last) and C_max by 68% (spacer:no spacer treatment ratio, 167.9%; 90% CI, 144.1 to 195.6) and 99% (ratio, 198.7%; 90% CI, 164.4 to 240.2) for budesonide, and 77% (ratio, 176.6%; 90% CI, 145.1 to 215.0) and 124% (ratio, 223.6%; 90% CI, 189.9 to 263.3) for formoterol, respectively, compared with pMDI alone. Similarly, the lung exposure of budesonide and formoterol increased (AUC_(0-last) and C_max by 146% [ratio, 246.0%; 90% CI, 200.7 to 301.6] and 127% [ratio, 226.5%; 90% CI, 186.4 to 275.4] for budesonide, and 173% [ratio, 272.8%; 90% CI, 202.5 to 367.4] and 136% [ratio, 236.2%; 90% CI, 192.6 to 289.6] for formoterol, respectively) when the pMDI was administered through the spacer. When assessed by AUC_(0-last) quartile without spacer, subjects in the lowest exposure quartile (indicating poor inhalation technique) with Symbicort^® pMDI 160/4.5 μg/actuation (2 actuations) had markedly increased total systemic and lung exposure when the same dose was administered with the spacer. In contrast, for subjects in the highest exposure quartile with pMDI alone, total systemic and lung exposure of formoterol and budesonide was similar with and without the spacer. In the in vitro study, the fine particle dose (<5 μm) of both budesonide and formoterol from the spacer at delay time (i.e. pause period after actuation) = 0 s (instantaneous) after actuation was similar to the fine particle dose when not using the spacer. The delivered doses of budesonide and formoterol from the spacer were both lower compared with the doses administered without the spacer. There was also a decrease in delivered dose with increasing delay time.

CONCLUSIONS

The clinical study demonstrated that in subjects with poor inhalation technique the use of the AeroChamber Plus^® Flow-Vu^® spacer increased the bioavailability of Symbicort^® pMDI to a level observed in subjects with good inhalation technique without a spacer. The findings from the in vitro study support the fine particle dose characteristics of Symbicort^® pMDI with the AeroChamber Plus^® Flow-Vu^® spacer.

Optimizing the Delivery of Inhaled Medication for Respiratory Patients: The Role of Valved Holding Chambers

Valved holding chambers (VHCs) have been used with pressurized metered-dose inhalers since the early 1980s. They have been shown to increase fine particle delivery to the lungs, decrease oropharyngeal deposition, and reduce side effects such as throat irritation, dysphonia, and oral candidiasis that are common with use of pressurized metered-dose inhalers (pMDIs) alone. VHCs act as aerosol reservoirs, allowing the user to actuate the pMDI device and then inhale the medication in a two-step process that helps users overcome challenges in coordinating pMDI actuation with inhalation. The design of VHC devices can have an impact on performance. Features such as antistatic properties, effective face-to-facemask seal feedback whistles indicating correct inhalation speed, and inhalation indicators all help improve function and performance, and have been demonstrated to improve asthma control, reduce the rate of exacerbations, and improve quality of life. Not all VHCs are the same, and they are not interchangeable. Each pairing of a pMDI device plus VHC should be considered as a unique delivery system.

A review of the in vitro and in vivo valved holding chamber (VHC) literature with a focus on the AeroChamber Plus Flow-Vu Anti-static VHC

Valved holding chambers (VHCs) reduce the need for inhalation-actuation coordination with pressurized metered dose inhalers (pMDIs), reduce oropharyngeal drug deposition and may improve lung deposition and clinical outcomes compared to pMDIs used alone. While VHCs are thus widely advocated for use in vulnerable patient groups within clinical and regulatory guidelines, there is less consensus as to whether the performance differences between different VHCs have clinical implications. This review evaluates the VHC literature, in particular the data pertaining to large- versus small-volume chambers, aerosol performance with a VHC adjunct versus a pMDI alone, charge dissipative/conducting versus non-conducting VHCs, and facemasks, to ascertain whether potentially meaningful differences between VHCs exist. Inconsistencies in the literature are examined and explained, and relationships between in vitro and in vivo data are discussed. A particular focus of this review is the AeroChamber Plus® Flow-Vu® Anti-static VHC, the most recent iteration of the AeroChamber VHC family.

Implementation of a Policy Change: Replacement of Nebulizers by Spacers for the Treatment of Asthma in Children

BACKGROUND

Treatment using inhaled bronchodilators for asthma with a metered dose inhaler attached to a spacer device (MDI+S) was shown to be as efficient as nebulizers. Nevertheless, nebulizers remain the treatment of choice in most hospitals.

OBJECTIVES

To implement a policy change to improve asthma treatment in pediatric wards and the pediatric emergency department.

METHODS

The study was performed in the emergency department and pediatric wards of a university medical center. The study group comprised all children admitted with a diagnosis of asthma necessitating treatment. The medical and nursing staff of both the pediatric emergency department and the pediatric wards was trained how to use metered dose inhalers attached to spacers on a regular basis in asthmatic pediatric patients. At a preset date nebulizers were replaced by spacers and their use was monitored by the supervising physician. Salbutamol was administered by a metered dose inhaler (100 μg/puff) attached to a spacer device. The number of puffs was determined by severity of disease according to GINA recommendations. After 2 years the outcome and cost analysis were examined.

RESULTS

During 3 years since the initial policy change 92.5%, patients were treated with spacers throughout their hospital stay (emergency department and pediatric ward). Costs were reduced by an estimated 63%.

CONCLUSIONS

In view of its many advantages, replacing nebulizers by MDI+S for the treatment of acute asthma.is, feasible, if performed in collaboration with the staff, hospital authority and patients.

Inhaler spacer devices to treat asthma in children

Drawing on literature searches and professional experience, this article discusses the treatment of asthma with pressurised metered dose inhalers (pMDIs). It demonstrates the need for pMDIs, and presents the health and cost benefits of using a pMDI through a spacer device. Through the review and evaluation of studies, it demonstrates the importance of correct asthma management and the use of spacers. Although there are many types of spacer, and patients often have less than optimal technique, there is evidence to support the overall benefits of use against non-use.

Salbutamol with metered dose inhalers with spacers - an established emergency treatment for preschool wheeze

AIMS

Metered dose inhalers (MDI) with spacers were implemented to treat preschool wheeze in the emergency room (ER) and hospital in 2006 in our children's hospital. The implementation at day time happened successfully within 4 months, but not at night time. The objective of the present study was to check the treatment mode, hospitalization rate and length of hospital stay (LOS) 4 years later.

METHODS

The present retrospective hospital chart review was identical to the review 4 years earlier, including data collection on treatment mode in 1- to-5-year-old preschool wheezers in the ER, on need of hospitalization, on treatment mode in hospital and on LOS. Both studies were performed during the same late-autumn and early-winter months.

RESULTS

In the ER, 96% of the children with preschool wheeze were treated with salbutamol using MDIs with spacers. Hospitalization rate was 51%, and all but one were treated with MDIs with spacers in hospital at both day and night time. Mean LOS was 2.48 days, being shorter than 4 years earlier.

CONCLUSION

Administration of salbutamol using MDI with spacer became an established emergency treatment of preschool wheeze within 4 years after the initial change from nebulizers to MDIs with spacers.

Effect of AeroChamber Plus™ on the lung and systemic bioavailability of beclometasone dipropionate/formoterol pMDI

AIM

To assess the effect of AeroChamber Plus™ on lung deposition and systemic exposure to extra-fine beclometasone dipropionate (BDP)/formoterol (100/6 µg) pMDI (Foster®). The lung deposition of the components of the combination given with the pMDI was also evaluated using the charcoal block technique.

METHODS

Twelve healthy male volunteers received four inhalations of extra-fine BDP/formoterol (100/6 µg) using (i) pMDI alone, (ii) pMDI and AeroChamber Plus™ and (iii) pMDI and charcoal ingestion.

RESULTS

Compared with pMDI alone, use of AeroChamber Plus™ increased the peak plasma concentrations (C(max)) of BDP (2822.3 ± 1449.9 vs. 5454.9 ± 3197.1 pg ml(-1)), its active metabolite beclometasone 17-monopropionate (17-BMP) (771.6 ± 288.7 vs. 1138.9 ± 495.6 pg ml(-1)) and formoterol (38.4 ± 17.8 vs. 54.7 ± 20.0 pg ml(-1)). For 17-BMP and formoterol, the AUC(0,30 min), indicative of lung deposition, was increased in the AeroChamber Plus™ group by 41% and 45%, respectively. This increase was mainly observed in subjects with inadequate inhalation technique. However, use of AeroChamber Plus™ did not increase the total systemic exposure to 17-BMP and formoterol. Results after ingestion of charcoal confirmed that AUC(0,30 min) can be taken as an index of lung bioavailability and that more than 30% of the inhaled dose of extra-fine BDP/formoterol 100/6 µg was delivered to the lung using the pMDI alone.

CONCLUSIONS

The use of AeroChamber Plus™ optimizes the delivery of BDP and formoterol to the lung in subjects with inadequate inhalation technique. The total systemic exposure was not increased, supporting the safety of extra-fine BDP/formoterol pMDI with AeroChamber Plus™.

Emergency treatment of obstructive bronchitis: change from nebulizers to metered dose inhalers with spacers

AIM

To evaluate how the change from drug nebulizers to metered dose inhalers (MDI) with spacers succeeded and influenced the hospitalization rate and the length of the emergency room (ER) and hospital stay in wheezing preschool-aged children.

METHODS

After educating and training the nurses and physicians, the use of MDIs with spacers was started on 1 November 2006 in the ER and acute wards of our hospital. All of the 1-to-5-year-old patients admitted for bronchial obstruction from 1 November 2004 to 28 February 2005 and from 1 November 2006 to 28 February 2007 were included in this retrospective hospital chart review.

RESULTS

In 2004-2005, 78% of the children were treated with salbutamol administered by nebulizers, and in 2006-2007, 84% with salbutamol administered by MDIs with spacers. The hospitalization rate was about 50% in both groups, and no difference was seen in the length of the hospital stay. The children treated with the MDIs with spacers stayed in the ER for a longer time.

CONCLUSION

The change from drug nebulizers to MDIs with spacers in the treatment of acute bronchial obstruction in 1-to-5-year-old children was successful after the staff was educated and trained.

Japanese guideline for childhood asthma

The Japanese Guideline for the Diagnosis and Treatment of Allergic Diseases 2010 (JAGL 2010) describes childhood asthma based on the Japanese Pediatric Guideline for the Treatment and Management of Asthma 2008 (JPGL 2008) published by the Japanese Society of Pediatric Allergy and Clinical Immunology. JAGL 2010 provides information on diagnosis by age groups from infancy to puberty, treatment for acute exacerbations, long-term management by medication, daily life guidance, and patient education to allow physicians, not specialized in childhood asthma, to refer to this guideline for routine medical treatment. JAGL differs from the Global Initiative for Asthma Guideline (GINA) in that the former emphasizes long-term management of childhood asthma based on asthma severity and early diagnosis and intervention at <2 years and 2-5 years of age. However, a management method, including step-up or step-down of long-term management agents based on the status of asthma symptoms, is easy to understand and thus JAGL is suitable for routine medical treatment. JAGL also introduced treatment and management using a control test for children, recommending treatment and management aimed at complete control through avoiding exacerbation factors and appropriate use of antiinflammatory agents.

Comparison of salbutamol efficacy in children--via the metered-dose inhaler (MDI) with Volumatic spacer and via the dry powder inhaler, Easyhaler, with the nebulizer--in mild to moderate asthma exacerbation: a multicenter, randomized study

BACKGROUND

Beta(2) agonist administered via a nebulizer is the standard treatment for acute asthma exacerbation. There are some limitations for the use of nebulization. We conducted a study to determine the efficacy of salbutamol administered via the pMDI with Volumatic spacer and the Easyhaler (DPI) compared to nebulization in mild to moderate asthma exacerbations in children.

METHODS

A multicenter, randomized, controlled study was conducted in children between 5 and 18 years of age who presented at an emergency or outpatient department. They were randomized to receive either 6 puffs of salbutamol via the pMDI with Volumatic spacer, or via the Easyhaler, or 0.15 mg/kg of salbutamol nebulized via oxygen (or compressed air). The primary outcome was the clinical response which was assessed using the modified Wood's asthma score. The secondary outcomes were: hospitalization, asthma revisit within 3 days, systemic corticosteroid use and adverse events. The clinical score, oxygen saturation, PR, RR, BP and adverse events were recorded at time 0 (before treatment) and 20, 40 and 60 minutes after drug administration.

RESULTS

There were no statistically significant differences in the clinical response between the three groups at the 1st, 2nd or 3rd dose or for the SpO(2) or the respiratory rate while the children in the Easyhaler group had significantly less tachycardia after the 2nd dose. No significant adverse events were noted among the three groups.

CONCLUSIONS

Salbutamol administered via pMDI with Volumatic spacer or DPI (Easyhaler) are as effective as salbutamol given via a nebulizer in providing effective relief of mild to moderate severity acute asthma exacerbation in children between 5 and 18 years of age.

A comparative study of efficacy of salbutamol via metered dose inhaler with volumatic spacer and via dry powder inhaler, easyhaler, to nebulization in mild to moderate severity acute asthma exacerbation in childhood

BACKGROUND

Rapid-acting inhaled beta-2 agonist is standard treatment in acute asthmatic patient; it causes smooth muscle dilatation, gives rapid action and has less side effect compared with parenteral and oral form. There are many forms of inhaler including nebulization, MDI and DPI. In Thailand the most common form of salbutamol administration for the treatment of acute exacerbation of asthma is via nebulization.

OBJECTIVE

To compare the clinical effectiveness and side effects of salbutamol via MDI with Volumatic spacer and via DPI (Easyhaler), with nebulization in mild to moderate severity of acute asthma exacerbation in childhood.

MATERIAL AND METHOD

A prospective, randomized controlled study in children, aged 5- 18-years-old with mild to moderate severe asthmatic attack, is done at the Emergency Room, QSNICH during October 2004 to February 2006. These children with acute asthma attack are randomly-assigned to 3 groups of different salbutamol administrations: group 1 via nebulization, group 2 via MDI with volumatic spacer and group 3 via DPI (Easyhaler). Salbutamol is administered and clinical responses: asthma score, oxygen saturation, PR, RR, BP and side effects (tremor and palpitation) are recorded at 0, 20, 40 and 60 minutes after the drug administrations. The drug will be repeated every 20 minutes for the total maximum of 3 times. If there is no clinical improvement, they will be admitted to the hospital for further management.

RESULTS

There are 54 asthmatic children, 35 male (64.8%) and 19 female (35.2%). Their mean age is 8.4 +/- 2.3 years. There are 18patients in each group. There is no significant difference in efficacy of salbutamol among the 3 groups as measured by asthma score, O2 saturation, PR, RR and BP Tremor are equally observed in all 3 groups (5.5%) while palpitation are observed in 11.1% of group 1 and 2 only. One patient in group 2 and 3 are admitted while no patient in group 1 is.

CONCLUSION

Rapid-acting inhaled beta-2 agonist via MDI with volumatic spacer and DPI (Easyhaler) can be used effectively compared with nebulization form in treating mild to moderate degrees of acute exacerbation of asthma in children with comparable side effects.

Computational analyses of a pressurized metered dose inhaler and a new drug-aerosol targeting methodology

The popular pressurized metered dose inhaler (pMDI), especially for asthma treatment, has undergone various changes in terms of propellant use and valve design. Most significant are the choice of hydrofluoroalkane-134a (HFA-134a) as a new propellant (rather than chlorofluorocarbon, CFC), a smaller exit nozzle diameter and attachment of a spacer in order to reduce ultimately droplet size and spray inhalation speed, both contributing to higher deposition efficiencies and hence better asthma therapy. Although asthma medicine is rather inexpensive, the specter of systemic side effects triggered by inefficient pMDI performance and the increasing use of such devices as well as new targeted drug-aerosol delivery for various lung and other diseases make detailed performance analyses imperative. For the first time, experimentally validated computational fluid-particle dynamics technique has been applied to simulate airflow, droplet spray transport and aerosol deposition in a pMDI attached to a human upper airway model, considering different device propellants, nozzle diameters, and spacer use. The results indicate that the use of HFA (replacing CFC), smaller valve orifices (0.25 mm instead of 0.5 mm) and spacers (ID = 4.2 cm) leads to best performance mainly because of smaller droplets generated, which penetrate more readily into the bronchial airways. Experimentally validated computer simulations predict that 46.6% of the inhaled droplets may reach the lung for an HFA-pMDI and 23.2% for a CFC-pMDI, both with a nozzle-exit diameter of 0.25 mm. Commonly used inhalers are nondirectional, and at best only regional drug-aerosol deposition can be achieved. However, when inhaling expensive and aggressive medicine, or critical lung areas have to be reached, locally targeted drug-aerosol delivery is imperative. For that reason the underlying principle of a future line of "smart inhalers" is introduced. Specifically, by generating a controlled air-particle stream, most of the inhaled drug aerosols reach predetermined lung sites, which are associated with specific diseases and/or treatments. Using the same human upper airway model, experimentally confirmed computer predictions of controlled particle transport from mouth to generation 3 are provided.

Novel spacer device does not improve adherence in childhood asthma

The Funhaler (FH) is a novel spacer device (holding chamber) that has been designed to improve adherence and aerosol delivery in young asthmatic children using a metered dose inhaler. A pilot study reported a 38% increase in parent-reported adherence over 2 weeks compared with the child's normal spacer. The aim of this study was to investigate whether the FH would be associated with superior adherence in the medium term (3 months) using an objective assessment. Forty-seven children aged 18 months to 7 years were randomised to a FH or control small volume spacer. Participants were reviewed monthly for 3 months. Adherence was measured using an electronic monitoring device (Smartinhaler). Disease control was based on symptom scores and exacerbation rates. Twenty-six children were randomised to the FH and 21 to the control spacer. Three children withdrew (FH = 2). Median adherence each month for the 3 months was 74%, 54%, and 46% for the FH and 70%, 73%, and 54% for the control spacer. The difference in adherence was not statistically significant (P = 0.47, 0.37, and 0.23, respectively). There was also no significant difference in exacerbation rates or symptom scores. Seven of the FHs broke during the study. The FH was preferred by 21/24 parents randomised to the FH compared with their child's normal spacer. Despite the FH being popular with children and parents its use was not associated with improved adherence or disease control.

Randomized trial of spacers in asthma

OBJECTIVE

To compare the efficacy of all types of spacers commonly available to children in India.

METHODS

150 children 5-14 yr of age with persistent asthma presenting with peak expiratory flow (PEF) < 70% of personal best were randomized to receive 200 mg salbutamol through one of five spacers: A) 750 ml spacer with valve, B) 165 ml spacer with valve, C) 250 ml spacer without valve, D) 1000 ml indigenously made spacer without valve and E) 500 ml indigenously made spacer without valve. PEF measurement was repeated 15 minutes later. Children> 8 yr old performed spirometry in addition to PEF. Absolute change and percentage improvement of PEF and FEV1 were compared among the groups.

RESULTS

Subjects in all groups had comparable baseline demographic characteristics and PEF. All showed significant improvement in PEF and FEV1 over baseline values. The change in PEF and percentage improvement were comparable among all five groups (p=0.780 and p=0.955 respectively). Likewise change in FEV1 and percentage improvement were also comparable. The five groups showed no difference in efficacy, irrespective of severity of baseline airway obstruction.

CONCLUSION

The five spacers were equally efficacious for the delivery of bronchodilator in children with moderate persistent asthma presenting with airway obstruction.

Randomised controlled trial of the efficacy of a metered dose inhaler with bottle spacer for bronchodilator treatment in acute lower airway obstruction

BACKGROUND

Inhaled bronchodilator treatment given via a metered dose inhaler (MDI) and spacer is optimal for relief of bronchoconstriction. Conventional spacers are expensive or unavailable in developing countries, but there is little information on the efficacy of low-cost spacers in young children.

OBJECTIVE

To compare the response to bronchodilator treatment given via a conventional or a low-cost bottle spacer

METHODS

A randomised controlled trial of the efficacy of a conventional spacer compared with a bottle spacer for bronchodilator treatment in young children with acute lower airway obstruction. Bronchodilator treatment was given from an MDI via an Aerochamber or a bottle spacer. Clinical score and oximetry recording were carried out before and after 15 min of treatment. MDI-spacer treatment was repeated up to three times, depending on clinical response, after which nebulisation was used. The primary outcome was hospitalisation.

RESULTS

400 children, aged (median (25th-75th centile)) 12 (6-25) months, were enrolled. The number of children hospitalised (n = 60, 15%) was identical in the conventional and bottle spacer groups (n = 30, 15% in each). Secondary outcomes including change in clinical score (-2 (-3 to -1)), oxygen saturation (0 (-1 to 1)) and number of bronchodilator treatments (2 (1 to 3)) were similar in both groups. Oral corticosteroids, prescribed for 78 (19.5%) children, were given to a similar number in the conventional (37 (18.5%)) and bottle spacer groups (41 (20.5%)).

CONCLUSION

A low-cost bottle spacer is as effective as a conventional spacer for bronchodilator treatment in young children with acute obstruction of the lower airways.

Improved efficacy of aerosol delivery to distal airways in pediatric subjects using a new spacer mouth-mask

Aerosol nebulization is and most effective ways of treating airway diseases especially in children. Failure of inhaled asthma treatment is mainly due to inadequate deposition of drugs in the peripheral area of the lungs. The aim of this study was to compare the efficacy of a traditional mask and that of a new spacer mouth-mask (Nebula, Markos Mefar, Italy) when used with a jet nebulizer, by measuring aerosol deposition in the lungs, oropharynx, upper airways, and gastrointestinal tract. Twelve children without respiratory disease aged between 8 and 13 years were included in the study. Aerosol inhalation was performed using a jet nebulizer with 2 mL of saline solution containing 20 Mci of Tc99m-DTPA. The first group initially performed aerosol inhalation using a traditional facemask and then, one week later, using the new spacer mouth-mask. The second group performed aerosol inhalation using the new spacer mouth-mask first and then, one week later, using a traditional mask. Scintigraphic ventilation images were then obtained, and aerosol deposition in the trachea, oropharynx, lungs and stomach was measured. In the first group, the radioaerosol deposition in the peripheral lung area using the new spacer mouth-mask was greater 97.8 +/- 7.0 vs. 68.5 +/- 7.9 (p = 0.04). On the other hand, the oropharyngeal radioaerosol deposition was greater using the traditional mask: 50.2 +/- 5.2 vs 20.3 +/- 11.8 (p = 0.028). Similarly, in the second group the peripheral lung deposition was greater and the oropharyngeal deposition was less using the new spacer mouth-mask: 97.3 +/- 9.4 vs. 70.2 +/- 11.2 and 20.7 +/- 8.9 vs. 46.3 +/- 16.8 (p = 0.028 and 0.046 respectively). In conclusion, the new design of the spacer mouth-mask allows greater aerosol deposition in the peripheral lung area and less in other parts such as the oropharyngeal area, the central airways and the stomach.

Effect of Oropharyngeal Length in Drug Lung Delivery via Suspension Pressurized Metered Dose Inhalers

PURPOSE

To determine the effect of the oropharyngeal length in adults on the lung dose of a suspension pressurized metered dose inhaler, and whether employing small volume spacers can alter this role.

METHODS

Depositions of Ventolin Evohaler (100) microg in the oropharyngeal models of two healthy adult subjects with 17.1 cm (short cast) and 19.9 cm (long cast) centerline lengths via three small volume spacers [two spacers with 3 cm effective length but one with 6.5 cm2 (L3) and the other with 24.6 cm2 (L3W) cross sections, and the Optimiser] were studied.

RESULTS

Without using spacers, lung dose of the long cast (19.52 +/- 2.32 microg, mean +/- standard deviation) was significantly larger than that for the short cast (8.08 +/- 1.01 microg, p < 0.006). However, using the L3 spacer with the short cast made the lung dose (18.59 +/- 3.33 microg) similar to that for the long cast alone. Lung doses of the short cast (20.43 +/- 1.42 microg) and the long cast (30.81 +/- 1.84 microg) with the L3W spacer were similar to those with the L3 spacer. However, using the Optimiser spacer increased the lung dose for the short cast (22.27 +/- 6.03 microg) and significantly for the long cast (35.61 +/- 2.19 microg, p < 0.006) compared to those for the L3 spacer. Using spacers increased drug deposition in the oropharynx part of the short cast, and this reduced the lung dose compared to that for the long cast.

CONCLUSION

The oropharyngeal length in adults may affect the lung dose via the pMDIs, which may not be eliminated by using small volume spacers.

How pediatricians in Spain manage the first acute wheezing episode in an atopic infant. Results from the TRAP study

BACKGROUND

Although the treatment of asthma has been addressed in several guidelines, the management of the first acute wheezing episode in infants has not often been evaluated. We surveyed practicing pediatricians in Spain about the treatment they would provide in a simulated case.

MATERIAL AND METHODS

A random sample of 3000 pediatricians and physicians who normally treated children was surveyed. The questionnaire inquired about how they would treat a first mild-to-moderate wheezing attack in a 5-month-old boy with a personal and family history of allergy. Pediatricians were asked about their professional background.

RESULTS

A total of 2347 questionnaires were returned with useful data (78.2%). Most (90.4%) of the pediatricians would use a short-acting beta2 agonist (SABA) via a metered-dose inhaler with a spacer and a face mask or nebulizer. However, only 34.5% chose a SABA alone: 31.3% added an oral steroid and 27.6% added an inhaled corticosteroid (ICS). The factors associated with the use of ICS in the acute attack were: (1) lack of specific training in pediatrics (OR 1.45; 1.12-1.85) and (2) primary care health center setting (OR 1.31; 1.01-1.69) or rural setting (OR 1.28; 1.01-1.66). Forty-four percent did not recommend any follow-up treatment while 20.7% prescribed ICS as maintenance therapy. The factors related to this decision were the same as those described above.

CONCLUSIONS

The management of a first wheezing episode seems to meet published guidelines among Spanish pediatricians with formal training in pediatrics and in those who work in a hospital setting or in urban areas.

[Bronchodilators via metered-dose inhaler with spacer in the pediatric emergency department: what is the dosage?]

INTRODUCTION

Bronchodilators administrated through a metered-dose inhaler (MDI) with spacer are as effective as nebulizers in the treatment of acute asthma exacerbations in childhood. However, consensus is lacking on the most suitable dosage.

OBJECTIVE

To assess the effectiveness of distinct salbutamol and terbutaline doses delivered via an MDI with spacer for the treatment of acute asthma in the pediatric emergency department.

METHODS

This was a prospective, double-blind randomized study. All consecutive children (n = 324) between 2 and 14 years of age with acute asthma exacerbations treated in the pediatric emergency department between October 1 and November 30, 2004, were included. Two treatment groups were established: one group received a number of puffs equivalent to half the child's weight (1 puff of salbutamol = 100 microg and 1 puff of terbutaline = 250 microg) and the other group received a number of puffs equivalent to one-third of the child's weight.

RESULTS

Three hundred twenty-four episodes were studied; there were 164 children in the first group and 160 in the second. There were no significant differences between the two groups in the mean (6 SD) age (58.34 +/- 34.72 vs 66.04 +/- 36.45 months), arterial oxygen saturation (95.49 +/- 1.93 vs 95.56 +/- 1.97) or pulmonary score (4.04 +/- 1.55 vs 3.97 +/- 1.51) at recruitment and after treatment in the emergency department (arterial oxygen saturation [96.34 +/- 1.60 vs 96.18 +/- 1.77], pulmonary score [1.87 +/- 1.33 vs 1.64 +/- 1.31]). The number of doses administered (2.17 +/- 0.91 vs 2.24 +/- 1.00) and the hospitalization rate (8.56 % vs 6.87 %) were also similar in both groups.

CONCLUSIONS

The distinct bronchodilator doses administered via an MDI with spacer showed similar effectiveness. These findings should contribute to a reevaluation of the use of high doses of bronchodilators, at least in most acute asthma exacerbations in children.

Practical problems with aerosol therapy in COPD

Inhaled aerosol drugs commonly used by patients with chronic obstructive pulmonary disease include short-acting and long-acting bronchodilators, as well as corticosteroids. These agents are available in a variety of inhaler devices, which include metered-dose inhalers (MDI), breath-actuated MDIs, nebulizers, and, currently, 5 different models of dry powder inhaler (DPI). There is evidence to suggest that multiple inhaler types cause confusion among patients and increase errors in patient use. Problems with MDIs include failure to coordinate inhalation with actuation of the MDI, inadequate breath-hold, and inappropriately fast inspiratory flow. Lack of a dose counter makes determining the number of remaining doses in an MDI problematic. Patient misuse of MDIs is compounded by lack of knowledge of correct use among health-care professionals. Several factors often seen with elderly patients have been identified as predictive of incorrect use of MDIs. These include mental-state scores, hand strength, and ideomotor dyspraxia. Holding chambers and spacers are partially intended to reduce the need for inhalation-actuation coordination with MDI use. However, such add-on devices can be subject to incorrect assembly. Possible delays between MDI actuation and inhalation, rapid inspiration, chamber electrostatic charge, and firing multiple puffs into the chamber can all reduce the availability of inhaled drug. Because they are breath-actuated, DPIs remove the need for inhalation-actuation synchrony, but there is evidence that patient errors in use of DPIs may be similar to those with MDIs. One of the biggest problems is loading and priming the DPI for use, and this may be due to the fact that every DPI model in current use is different. Medical personnel's knowledge of correct DPI use has also been shown to be lacking. The optimum inhalation profiles are different for the various DPIs, but, generally, chronic obstructive pulmonary disease patients have been shown to achieve a minimum therapeutic dose, although the inhaled amount may be suboptimal. A limitation of DPIs that have multidose powder reservoirs (eg, the Turbuhaler) is ambient humidity, which can reduce the released dose. Small-volume nebulizers are limited by bulk, treatment time, and variable performance, but are easy for patients to use. Important features identified by patients for an ideal inhaler are ease of use during an attack, dose counter, and general ease of use and learning. A breath-actuated-pMDI, such as the Autohaler, ranked at the top of inhaler preference in a study of 100 patients with airflow obstruction, compared to DPIs and MDIs. Short of a universal simple inhaler, patient and caregiver education remains the best solution to correct patient errors in use.

Force-dependent static dead space of face masks used with holding chambers

BACKGROUND

Pressurized metered-dose inhalers with valved holding chambers and masks are commonly used for aerosol delivery in children. Drug delivery can decrease when the dead-space volume (DSV) of the valved holding chamber is increased, but there are no published data evaluating force-dependent DSV among different masks.

METHODS

Seven masks were studied. Masks were sealed at the valved holding chamber end and filled with water to measure mask volume. To measure mask DSV we used a mannequin of 2-year-old-size face and we applied the mask with forces of 1.5, 3.5, and 7 pounds. Mask seal was determined by direct observation. Intra-brand analysis was done via analysis of variance.

RESULTS

At 3.5 pounds of force, the DSV ranged from 29 mL to 100 mL, with 3 masks having DSV of < 50 mL. The remaining masks all had DSV > 60 mL. At 3.5 pounds of force, DSV percent of mask volume ranged from 33.7% (Aerochamber, p < 0.01 compared with other masks) to 100% (Pocket Chamber). DSV decreased with increasing force with most of the masks, and the slope of this line was inversely proportional to mask flexibility. Mask fit was 100% at 1.5 pounds of force only with the Aerochamber and Optichamber. Mask fit was poorest with the Vortex, Pocket Chamber, and BreatheRite masks.

CONCLUSION

Rigid masks with large DSV might not be not suitable for use in children, especially if discomfort from the stiff mask makes its use less acceptable to the child.

[Metered-dose inhaler with spacer vs nebulization for severe and potentially severe acute asthma treatment in the pediatric emergency department]

OBJECTIVE

To compare treatment with beta 2 agonist delivered either by a spacer device or a nebulizer in children with severe or potentially severe acute asthma.

METHODS

In this randomized trial, children 4 to 15 years, cared for in the emergency department for severe or potentially severe acute asthma, received 6 times either nebulizations of salbutamol (0.15mg/kg) or puffs of a beta 2 agonist (salbutamol 50 microg/kg or terbutaline 125 microg/kg). The primary outcome was the hospitalization rate. Secondary outcomes included percentage improvement in Bishop score, in PEF, SaO(2), respiratory and heart rates, side effects, length of stay and relapses 10 and 30 days later.

RESULTS

Groups did not differ for baseline data. There were no significant differences between the 2 groups (nebulizer N=40, spacer N=39) for baseline characteristics before emergency department consultation except for length of acute asthma in the spacer group. Clinical evolution after treatment, hospitalization rate, relapse were similar including the more severe subgroup. In the spacer group, tachycardia was less frequent (P<0.02). The overall length of stay in the emergency department was significantly shorter (148+/-20 vs 108+/-13 min, P<10(-9)).

CONCLUSIONS

The administration of beta 2 agonist using a metered-dose inhaler with spacer is an effective alternative to nebulizers for the treatment of children with severe or potentially severe acute asthma in the emergency department. Time gained can be used for asthma education.

Artificial Neural Network Prediction of the Patterns of Deposition of Polydisperse Aerosols Within Human Lungs

For optimum therapeutic response from drug administered to the lungs, it is paramount that the aerosolised drug is able to deposit in the lower airways. The filtering characteristics of the respiratory tract, however, make this a particularly challenging task. Computational tools afford a cost-effective means of studying the problem, and here we report on the development of a rapid and reliable method for predicting the pattern of deposition of polydisperse aerosols within human lungs using artificial neural networks (ANNs). Literature (experimental) data on lung deposition of monodisperse aerosols were used to train a single ANN to allow for simultaneous predictions of regional and total aerosol particle deposition patterns in human lungs. When used in modelling the fate of polydisperse aerosols in human lungs, the trained ANN was found to give highly accurate predictions for all lung regions, and all (pharmaceutically relevant) particle sizes and breathing conditions (with errors typically <0.025%). Further testing of the ANN, using 'unseen' in vitro and in vivo data, gave good agreement of lung dosages. It is thus concluded that the ANN produced can be used to provide highly reliable estimates of particle deposition from polydisperse pharmaceutical aerosols generated from breath-actuated dry powder inhalers, nebulizers and metered dose inhalers with spacers.

Principles of metered-dose inhaler design

The pressurized metered-dose inhaler (pMDI) was introduced to deliver asthma medications in a convenient and reliable multi-dose presentation. The key components of the pMDI device (propellants, formulation, metering valve, and actuator) all play roles in the formation of the spray, and in determining drug delivery to the lungs. Hence the opportunity exists to design a pMDI product by adjusting the formulation, metering-valve size, and actuator nozzle diameter in order to obtain the required spray characteristics and fine-particle dose. Breath-actuated pMDIs, breath-coordinated pMDIs, spray-velocity modifiers, and spacer devices may be useful for patients who cannot use a conventional press-and-breathe pMDI correctly. Modern pMDI devices, which contain non-ozone-depleting propellants, should allow inhalation therapy via pMDI to extend well into the 21st century for a variety of treatment indications.

Optimizing aerosol delivery by pressurized metered-dose inhalers

The modern era of aerosol therapy began with the introduction of the Medihaler Epi in 1956, after a 13-year-old asthmatic told her father, an officer in the Riker company, that asthma medications should be as convenient to use as hair spray and she complained that the bulb atomizer leaked in her school bag. Since then, advances in technology have made aerosol delivery much more efficient, so that it is now the most widely used mode of medication delivery for chronic airways diseases. Today the pressurized metered-dose inhaler (pMDI) is a metal canister containing a mixture of propellants, surfactants, preservatives, and drug. However, pMDIs are underused in the United States. One barrier to use is the misconception related to pMDI effectiveness relative to small-volume nebulizers, especially among pediatricians. This is despite the strongest evidence of pMDI superiority, from well-controlled pediatric studies. In this manuscript we discuss ways to optimize the use of medications given via pMDI and examine recent changes in pMDI technology that will make drug delivery more efficient and consistent.

Aerosol delivery to young children by pMDI-spacer: is facemask design important?

This study aimed at identifying in a daily-life setting the influence of facemask design on drug delivery via a spacer to young children. In a 4-week randomized crossover study, 24 children (7-23-months old) with recurrent wheeze tested the AstraZeneca, Galemed, and Hans Rudolph facemask combined with the NebuChamber at home. Each mask was tested twice daily for seven consecutive days. Filters positioned between the NebuChamber and facemask trapped the budesonide aerosol (200 microg, Pulmicort). Parents were asked to score the child's degree of cooperation during administration on diary cards. The administration procedure was evaluated through video recordings. Mean filter dose (standard deviation (s.d.)), expressed as % of nominal dose, was 39% (14), 47% (12), and 42% (11) for the AstraZeneca, the Galemed and the Hans Rudolph mask, respectively. Irrespective of the degree of cooperation, the Galemed mask gave significantly higher mean filter doses than the other masks (level of significance) (p < 0.045). Median (range) within-subject dose variability, expressed, as coefficient of variation (CV), was 37% (19-255), 32% (9-114), and 30% (9-115) for the AstraZeneca mask, the Galemed mask and the Hans Rudolph mask, respectively, not significant. Dose variability increased with decreasing cooperation for all three masks (p = 0.007). Drug delivery to young children with recurrent wheeze by means of the NebuChamber can be enhanced using the Galemed facemask. Dose variability seems to be independent of facemask design but mainly depends on cooperation.

Randomized controlled trial of salbutamol aerosol therapy via metered dose inhaler-spacer vs. jet nebulizer in young children with wheezing

The jet nebulizer is a common device used for administering aerosol medication in young children. However, compared to a metered dose inhaler-spacer (MDI-spacer), it takes more time and personnel. This study aimed to compare the efficacy of salbutamol aerosol therapy given via these two devices in young wheezing children. A prospective randomized, double-blind, placebo-controlled trial was performed in children up to 5 years old who had acute wheezing and were admitted to the Department of Pediatrics, King Chulalongkorn Memorial Hospital. Patients were randomly divided into two groups. The first group received 2 puffs of placebo via MDI-spacer, followed by 0.15 mg/kg salbutamol respiratory solution via jet nebulizer. The second group received 2 puffs (100 microg/puff) of salbutamol via MDI-spacer, followed by placebo via jet nebulizer. Clinical scores and tidal breathing pulmonary function test were evaluated before and after treatment. Pulmonary function parameters included those derived from flow volume loops (volume to peak tidal expiratory flow over total expiratory volume, V(PTEF)/V(E); time to peak tidal expiratory flow over total expiratory time, T(PTEF)/T(E); and ratio of tidal expiratory flow at 25% remaining expiration to peak expiratory flow, 25/PF), compliance (Crs), and resistance (Rrs) of the respiratory system. The efficacy of both methods was compared by using analysis of covariance. Forty-seven wheezing children were studied (24 received salbutamol via MDI-spacer, and 23 received it via jet nebulizer). There was no statistical difference between the two groups regarding clinical scores and all pulmonary function parameters. However, heart rate was significantly increased after treatment in the jet nebulizer group when compared to those in the MDI-spacer group (P = 0.004). In conclusion, the efficacy of salbutamol aerosol therapy via MDI-spacer compared to jet nebulizer in young wheezing children was not different in terms of clinical score and postbronchodilator pulmonary function parameters. However, salbutamol aerosol therapy via jet nebulizer significantly increased the heart rate when compared to the MDI-spacer.

A new asthma spacer device to improve compliance in children: a pilot study

OBJECTIVE

This pilot study was designed to compare the acceptance, ease of use, and effects on compliance between currently used spacer devices and the Funhaler--a new small volume spacer device designed to improve adherence to asthma medication in children.

METHODOLOGY

A matched questionnaire-based survey was conducted by two interviews of each caregiver by the same person. A total of 32 children were randomly recruited from seven clinics spanning widely differing socioeconomic and geographical areas of Perth, Western Australia. Preschool children taking regular inhaled asthma medication using an existing low volume spacer device and aged between 1.5 and 6 years, took part in the pilot study. Parents completed two matched questionnaires. The first questionnaire was completed at the beginning of the study and the second after 2 weeks' use of the Funhaler spacer. Data collected related primarily to ease of use of the devices, child and parental compliance, and treatment attitudes. During the study, parents were also called at random on one occasion to ascertain whether they had attempted to medicate their child the previous day.

RESULTS

Using the Funhaler incentive spacer device, parents reported significantly more success at medicating their children (22/30 always successful) in comparison to using their existing spacer device (3/30). Parental adherence to prescribed frequency and the delivery technique of children were also improved. The children also showed improved satisfaction and willingness to use the device and parents' attitude towards medicating their children was improved with the Funhaler spacer device.

CONCLUSIONS

Use of a novel, incentive spacer device (Funhaler) appeared to be associated with increased success and fewer problems in medicating children, improved child and parental adherence, and a more positive attitude towards treatment, suggesting that more extensive long-term efficacy trials with the device are warranted.

Dynamic change of the upper airway during inhalation via aerosol delivery devices

Although it is likely that the upper airway is a major factor in the large inter- and intra-subject variation in deposition of inhaled drug aerosols in the lung, data on the configuration of the upper airway during inhalation is sparse. We have developed a unique method, using magnetic resonance imaging, to reconstruct the upper airway in three dimensions during inhalation from aerosol devices used to deliver medication to patients with asthma, chronic obstructive pulmonary disease, and cystic fibrosis. Ten healthy adults were imaged while inhaling from a pressurized metered dose inhaler (pMDI), a spacer used with pMDI (spacer), and a high-resistance dry powder inhaler, the Turbuhaler (DPI). The mean cross-sectional area of the oropharyngeal region was significantly larger (Wilcoxon's signed-rank test with Bonferroni correction, p < 0.0167) when the DPI (281 [143] mm2, mean [SD]) was used compared to the spacer (205 [32] mm2, p = 0.016) or pMDI (152 [48] mm2, p = 0.013). Considerable variations in the cross-sectional areas of the oral cavity, oropharynx, and larynx were seen when compared to the upper trachea. The main cause for this was the varying position of the tongue during inhalation via the devices. Although differences were observed when comparing the total volume of the upper airway during inhalation via the DPI (70 [17] cm3) to the pMDI (56 [20] cm3, p = 0.037) or spacer (59 [12] cm3, p = 0.022), these did not reach significance. This study shows that there are very significant variations in the configuration of the upper airway when different devices are used for inhalation. These changes are likely to be produced by a number of factors, including tongue position, device airflow resistance, and patient effort.

Device Selection and Outcomes of Aerosol Therapy: Evidence-Based Guidelines

BACKGROUND

The proliferation of inhaler devices has resulted in a confusing number of choices for clinicians who are selecting a delivery device for aerosol therapy. There are advantages and disadvantages associated with each device category. Evidence-based guidelines for the selection of the appropriate aerosol delivery device in specific clinical settings are needed.

AIM

(1) To compare the efficacy and adverse effects of treatment using nebulizers vs pressurized metered-dose inhalers (MDIs) with or without a spacer/holding chamber vs dry powder inhalers (DPIs) as delivery systems for beta-agonists, anticholinergic agents, and corticosteroids for several commonly encountered clinical settings and patient populations, and (2) to provide recommendations to clinicians to aid them in selecting a particular aerosol delivery device for their patients.

METHODS

A systematic review of pertinent randomized, controlled clinical trials (RCTs) was undertaken using MEDLINE, EmBase, and the Cochrane Library databases. A broad search strategy was chosen, combining terms related to aerosol devices or drugs with the diseases of interest in various patient groups and clinical settings. Only RCTs in which the same drug was administered with different devices were included. RCTs (394 trials) assessing inhaled corticosteroid, beta2-agonist, and anticholinergic agents delivered by an MDI, an MDI with a spacer/holding chamber, a nebulizer, or a DPI were identified for the years 1982 to 2001. A total of 254 outcomes were tabulated. Of the 131 studies that met the eligibility criteria, only 59 (primarily those that tested beta2-agonists) proved to have useable data.

RESULTS

None of the pooled metaanalyses showed a significant difference between devices in any efficacy outcome in any patient group for each of the clinical settings that was investigated. The adverse effects that were reported were minimal and were related to the increased drug dose that was delivered. Each of the delivery devices provided similar outcomes in patients using the correct technique for inhalation.

CONCLUSIONS

Devices used for the delivery of bronchodilators and steroids can be equally efficacious. When selecting an aerosol delivery device for patients with asthma and COPD, the following should be considered: device/drug availability; clinical setting; patient age and the ability to use the selected device correctly; device use with multiple medications; cost and reimbursement; drug administration time; convenience in both outpatient and inpatient settings; and physician and patient preference.

Comparison of efficiency and preference of metal and plastic spacers in preschool children

BACKGROUND

The metal NebuChamber valved holding chamber (VHC) has gained wide acceptance among children with asthma. Due to its nonelectrostatic properties and larger volume, the 250-mL, metal NebuChamber delivers a greater mass of aerosol to a filter at the mouth compared with the commonly used 150-mL polypropylene AeroChamber VHC. Such in vitro results have been used to suggest that this may provide increased efficacy with the NebuChamber. No comparative efficacy data exist for preschool children with asthma.

OBJECTIVE

To compare efficiency and preference of metal and plastic spacers in preschool children.

METHODS

Children with mild-to-moderate persistent asthma received 200 microg of budesonide twice daily by NebuChamber or AeroChamber, both with the mask provided in a randomized, 2-month, crossover trial. Symptom diary cards, beta-agonist use, and preference by children and parents were compared.

RESULTS

Thirty children (mean +/- SD age, 4.3 +/- 0.3 years) completed the study. There was no difference between the AeroChamber and NebuChamber in clinical efficacy outcomes. There was no difference between the AeroChamber and NebuChamber in parents' view of ease of use, design, acceptability by the children, and overall satisfaction.

CONCLUSIONS

Despite a greater total dose delivered to the mouth, the NebuChamber appears no more effective than the AeroChamber and it is not preferred by patients or parents. More parents chose to continue to use the NebuChamber after the study.

[Evaluation of the influence of patient age and spacer device volume on aerosol lung deposition]

OBJECTIVE

To evaluate the efficacy of three frequently used spacer devices to deliver aerosol to the lung, and to compare radioaerosol deposition with each device in different age groups.

METHODS

Nine healthy, non-smoking volunteers were recruited: three adults and six children, including three toddlers and three school age children. Qualitative and semi-quantitative analysis of radioaerosol deposition in the lung were carried out. Yet, two small-volume devices (Aerochamber and Inal-Air) and one large-volume device (Flumax) were compared. Each patient inhaled 99mtechnetium-phytate. The device was filled during 30 seconds with radioaerosol. Oxygen was used as the driving gas. During 10 seconds, the patients inhaled the radioaerosol. The radiation emitted at the front and back of the chest was measured. The radiation inside the device was also measured.

RESULTS

The quantitative evaluation of lung deposition revealed that the younger the patient, the less aerosol was deposited in the lung with the large-volume spacer device (Flumax). The difference between small-volume devices (Aerochamber and Inal-Air) was not significant.

CONCLUSION

Small-volume spacers are the most appropriate for children. Large-volume devices should only be used by adolescents and adults.

Albuterol delivery from a metered-dose inhaler with spacer is reduced following short-duration manual ventilation in a neonatal ventilator-lung model

INTRODUCTION

Albuterol aerosol is commonly administered to mechanically ventilated neonates via metered-dose inhaler (MDI) with spacer. The spacer increases the dead space in the ventilation circuit, and some institutions limit the amount of time the spacer remains in line, to minimize carbon dioxide retention and the risk of hypercarbia. However, minimizing the amount of time the spacer remains in line might also limit albuterol delivery to the patient.

OBJECTIVE

To determine whether limiting the amount of time the spacer is left in line after MDI actuation significantly reduces albuterol delivery.

METHODS

We conducted a bench study with a neonatal ventilator-lung model that included a Bird VIP ventilator, in a time-cycled, pressure-limited, continuous-flow mode, with settings to simulate a 1-kg infant with moderate lung disease: peak inspiratory pressure 25 cm H2O, positive end-expiratory pressure 4 cm H2O, respiratory rate 30 breaths/min, inspiratory time 0.35 s, tidal volume approximately 7 mL. The circuit was attached to a 3.0-mm inner-diameter endotracheal tube and a neonatal test lung. We tested 5 methods of MDI albuterol administration. The first 3 methods used a spacer attached to the ETT and either 5, 15, or 30 manual breaths (flow 6 L/min, respiratory rate 30 breaths/min, peak inspiratory pressure 25 cm H2O) were delivered after each MDI actuation (2 actuations). The final 2 methods used an in-line spacer (placed between the circuit Y-piece and the endotracheal tube) with the spacer kept in line for 30 or 60 s after each actuation (2 actuations). A breathing filter was placed between the ETT and test lung to trap the aerosolized albuterol.

RESULTS

Mean +/- SD albuterol delivery was 2.3 +/- 0.5%, 3.6 +/- 1.8%, and 5.1 +/- 1.3% after 5, 15, and 30 manual breaths, respectively (p < or = 0.05 for 30 breaths vs 5 and 15 breaths). Albuterol delivery was 3.7 +/- 1.3% when the spacer was left in line for 30 s, versus 3.7 +/- 0.6% when it was left in line for 60 s.

CONCLUSIONS

Limiting the time that the spacer was left in line after each MDI actuation significantly reduced albuterol delivery in our neonatal ventilator-lung model.

Comparison of patient preference and ease of teaching inhaler technique for Pulmicort Turbuhaler versus pressurized metered-dose inhalers

A multicenter, randomized, open-label, crossover study with two 4-week evaluation periods compared patient preference and ease of teaching correct inhaler technique for Pulmicort Turbuhaler versus pressurized metered-dose inhalers (pMDIs). Patients 18 to 65 years of age with stable, mild to moderate asthma, who required or were eligible for inhaled corticosteroid therapy, were randomized to treatment sequences consisting of 4-week evaluation periods with Pulmicort Turbuhaler (budesonide inhalation powder) two puffs (400 microg) bid and one of three inhaled corticosteroids via pMDI: Aerobid-M (flunisolide) four puffs (1 mg) bid, Flovent (fluticasone propionate) two puffs (440 microg) bid, or Vanceril Double Strength (beclomethasone dipropionate) five puffs (420 microg) bid. Patients indicated device preference at study end and completed the Patient Device Experience Assessment (PDEA) questionnaire after each evaluation period. Ease of teaching, time required to master use of the device, percentage of patients demonstrating mastery on the first attempt, and the number of attempts required to demonstrate mastery were assessed. Despite previous use of pMDIs by most patients, Pulmicort Turbuhaler was significantly preferred (p < 0.001) and required significantly less time to master than pMDIs (p < 0.001). Median times to device mastery were 3.67 min for Pulmicort Turbuhaler versus 5.33 min for pMDIs. Patients rated Pulmicort Turbuhaler significantly better than pMDIs on PDEA ease of use (p = 0.0005) and overall satisfaction (p < 0.0001) single-item scales and all four multi-item scales (pharyngeal symptoms, oral sensation, operational use, and inhaler attributes; p < 0.05). Overall, patients preferred Pulmicort Turbuhaler over pMDIs and required less time to be taught how to correctly use Turbuhaler trade mark.

In Vitro Performance Characteristics of Valved Holding Chamber and Spacer Devices with a Fluticasone Metered-Dose Inhaler

STUDY OBJECTIVE

To compare the in vitro aerosol deposition characteristics of several commercially available valved holding chamber (VHC) and spacer devices used with a fluticasone metered-dose inhaler (MDI).

DESIGN

In vitro aerosol deposition study

SETTING

University-affiliated research center.

DEVICES

Seven VHC devices: BreatheRite, E-Z Spacer, EasiVent, AeroChamber, InspirEase, OptiChamber, and Space Chamber. Six spacer devices: OptiHaler, Aerosol Cloud Enhancer (ACE), Gentle-Haler, MediSpacer, Ellipse, and a 6-inch tube (1-inch inside diameter).

INTERVENTION

The respirable dose (aerosol particles 1-5 microm) of fluticasone was determined by sampling 10 220-microg actuations from five runs with each spacer or VHC plus MDI combination, by using a well-established in vitro cascade impactor method.

MEASUREMENTS AND MAIN RESULTS

Fluticasone aerosol was washed from the impactor with methanol and quantified by means of high-performance liquid chromatography. Differences among outcomes were determined with analysis-of-variance testing. Among spacers, Ellipse had the highest respirable dose (104 microg, p < 0.01). Respirable doses for the 6-inch tube (74.3 microg), Gentle-Haler (81.7 microg), and MediSpacer (82.6 microg) were no different from that of the MDI (p > 0.05), whereas respirable doses of OptiHaler (44.6 microg) and ACE (47.2 microg) were less than those of all other spacers (p < 0.001). Among VHC devices, respirable doses from EasiVent (35.6 microg), AeroChamber (47.0 microg), InspirEase (52.7 microg), OptiChamber (53.1 microg), and Space Chamber (58.3 microg) were not different (p > 0.05), whereas BreatheRite (13.1 microg) and E-Z Spacer (27.3 microg) respirable doses were less than those of the other VHC devices (p < 0.05).

CONCLUSION

Spacers and VHC devices available in the United States do not demonstrate equivalent in vitro performance with the fluticasone MDI. The difference between highest and lowest respirable doses in each device category would likely lead to clinically relevant differences in the quantity of fluticasone delivered to a patient.

Albuterol aerosol delivered via metered-dose inhaler to intubated pediatric models of 3 ages, with 4 spacer designs

OBJECTIVE

To determine the amount of albuterol, in various particle size ranges, delivered from a hydrofluoroalkane-propelled metered-dose inhaler (Airomir) in 3 models of pediatric intubation (ages 8 months, 4 years, and 16 years) using 4 types of aerosol reservoir: 3 spacers (ACE, AeroChamber HC MV, metal NebuChamber without 1-way valve) and 1 holding chamber (metal NebuChamber with 1-way valve).

METHODS

Five reservoirs of each type were tested with albuterol sulfate delivered via metered-dose inhaler that delivers 100 microg of albuterol per actuation. Each reservoir was connected to an endotracheal tube (ETT) that corresponded to the given patient age (8 months = 4 French; 4 years = 5 French; 16 years = 7.5 French) and to a valved system that allowed connection of the ETT to a cascade impactor. Simulated tidal volumes representative of children of the given ages were passed through the reservoir. Both the cascade impactor and the ETT were enclosed within a 100% humidity, 37 degrees C environment.

RESULTS

For the total amount of albuterol inhaled onto the impactor, and both the 1.1-4.7 microm and 1.1-3.3 microm inhaled fine-particle fractions, the NebuChamber-with-valve showed significantly greater drug delivery than the NebuChamber-without-valve, the AeroChamber HC MV, or the ACE (p < 0.001). Among the reservoirs without valves the NebuChamber showed significantly greater delivery than the AeroChamber HC MV or ACE (p < 0.001) for total drug deposition and for both the 1.1-4.7 microm and 1.1-3.3 microm fine-particle fractions. These results were consistent over all age groups. The AeroChamber HC MV had significantly greater delivery (total deposition) than the ACE (p < 0.001), except in the 4-year-old model. There were no significant differences between the AeroChamber HC MV and the ACE for either the 1.1-4.7 microm or the 1.1-3.3 microm fine-particle fraction.

CONCLUSION

An aerosol reservoir with 1-way valve positioned between the spacer and the ETT improved the amount of inhaled albuterol 300-900%, compared to the other reservoirs.

Electrostatic charge on spacer devices and salbutamol response in young children

Electrostatic charge on plastic spacer devices may affect the efficacy of inhaled drugs, but its consequences have never been evaluated in asthmatic children with airflow limitation. At the end of a positive metacholine challenge, 64 children (51.3+/-12.9 months, 32 boys, specific airway resistance (SRaw) 257.1+/-56.7% and forced expiratory volume in 1s (FEV(1)) 64.2+/-17.9% of the predicted value) inhaled one puff of hydrofluoroalkane-134a (HFA-134a) salbutamol (Ventoline((R))), and 15min later two other puffs (total dose of 300 microgram), delivered through either a new static Babyhaler((R)) (n=21), a detergent-coated, reduced static, Babyhaler((R)) (n=20), or a metal NES-Spacer((R)) (n=23) equipped with facemask. SRaw and FEV(1) were measured after each treatment and compared between groups by a Kruskal-Wallis test. The first 100 microgram salbutamol induced a 151.7+/-43.9% decrease in SRaw and a 19.9+/-10.6% increase in FEV(1). Additional 200 microgram salbutamol allowed a supplementary decrease of 35.1+/-25.7% in SRaw and increase of 12.1+/-11.8% in FEV(1), without significant difference between the spacer devices. Electrostatic charge on spacer devices does not affect bronchodilation with HFA-134a salbutamol in metacholine-challenged pre-school children. This could be in part explained by the use of supramaximal doses of salbutamol.

Spacers and nebulisers for the delivery of beta-agonists in non-life-threatening acute asthma

BACKGROUND

In asthma exacerbations, higher doses of inhaled beta-agonists are used to overcome acute bronchoconstriction. Traditionally, wet nebulisation has been used, but metered-dose inhaler with a spacer device is an alternative delivery method.

OBJECTIVE

To compare the clinical outcomes in adults and children with acute asthma, presenting in emergency departments or in the community, who have been randomised to beta-agonists given by two different delivery.

METHODS

a metered-dose inhaler with spacer or a nebuliser.

RESULTS

A Cochrane review has found no important differences between the two delivery methods in adults. Children may suffer fewer side effects with spacer delivery.

CONCLUSIONS

Individual response to treatment cannot be predicted, but many studies overcame this problem by using frequent repeated doses of beta-agonists (one respule via nebuliser or four separate actuations of a metered-dose inhaler through a spacer) every 10-15 min, titrated against the clinical response of the patients. This approach is advocated in clinical practice.