Comparison of twenty three nebulizer/compressor combinations for domiciliary use

Interchanging Reusable and Disposable Nebulizers Used with Home-Based Compressors May Result in Inconsistent Dosing: A Laboratory Investigation with Device Combinations Supplied to the US Healthcare Environment

INTRODUCTION

Reusable nebulizer-compressor combinations deliver inhaled medications for patients with chronic lung diseases. On hospital discharge, the patient may take home the disposable nebulizer that was packaged and combine it with their home compressor. Though this practice may reduce waste, it can increase variability in medication delivery. Our study compared several reusable and disposable nebulizers packaged with compressor kits used in the US. We included a common disposable hospital nebulizer that may not be supplied with popular home kits but may be brought home after a hospitalization or emergency department visit. We focused on fine droplet mass < 4.7 μm aerodynamic diameter (FDM<4.7 μm), associated with medication delivery to the airways of the lungs.

METHODS

We evaluated the following nebulizer-compressor combinations (n = 5 replicates): 1. OMBRA® Table Top Compressor with MC 300® reusable and Airlife™ MistyMax™ 10® disposable nebulizer, 2. Sami-the-Seal® compressor with SideStream® reusable and disposable nebulizers and Airlife™ MistyMax 10™ disposable nebulizer, 3. VIOS® compressor with LC Sprint® reusable, and VixOne® and Airlife™ MistyMax™ disposable nebulizers, 4. Innospire® Elegance® compressor with SideStream® reusable and disposable nebulizers and Airlife™ MistyMax 10™ disposable nebulizer, 5. Willis-the-Whale® compressor with SideStream® reusable and disposable nebulizers and Airlife™ MistyMax 10™ disposable nebulizer, 6. Pari PRONEB® Max compressor with LC Sprint® reusable and Airlife™ MistyMax 10™ disposable nebulizer. We placed a 3-ml albuterol solution (0.833 mg/ml) in each nebulizer. A bacterial/viral filter was attached to the nebulizer mouthpiece to capture emitted medication, with the filter exit coupled to a simulator of a tidal breathing adult (rate = 10 cycles/min; Vt = 600 ml; I/E ratio = 1:2). The filter was replaced at 1-min intervals until onset of sputter. Droplet size distributions (n = 5 replicates/system) were determined in parallel by laser diffractometry.

RESULTS

Cumulative FDM<4.7 μm varied from 381 ± 33 μg for the best performing combination (Proneb/LC-Sprint) to 150 ± 21 μg for the system with the lowest output (VIOS®/MistyMax 10™).

CONCLUSIONS

Substituting one nebulizer for another can result in large differences in medication delivery to the lungs.

Evaluation of antibody drug delivery efficiency via nebulizer in various airway models and breathing patterns

BACKGROUND

Nebulizers are commonly used to treat respiratory diseases, which are a major cause of morbidity and mortality. While inhalation therapy with antibodies has been evaluated in preclinical studies and clinical trials for respiratory diseases, it has not yet been approved for treatment. Moreover, there is limited information regarding the delivery efficiency of therapeutic antibodies via nebulizer.

METHODS

In this study, the nebulization characteristics and drug delivery efficiencies were compared when immunoglobulin G (IgG) was delivered by five nebulizers using two airway models and five breathing patterns. The study confirmed that the delivered dose and drug delivery efficiency were reduced in the child model compared to those in the adult model and in the asthma pattern compared to those in the normal breathing pattern.

RESULTS

The NE-SM1 NEPLUS vibrating mesh nebulizer demonstrated the highest delivery efficiency when calculated as a percentage of the loading dose, whereas the PARI BOY SX + LC SPRINT (breath-enhanced) jet nebulizer had the highest delivery efficiency when calculated as a percentage of the emitted dose.

CONCLUSION

The results suggest that the total inspiration volume, output rate, and particle size should be considered when IgG nebulization is used. We, therefore, propose a method for evaluating the efficiency of nebulizer for predicting antibody drug delivery.

Low-dose intrapulmonary drug delivery device for studies on next-generation therapeutics in mice

Although nebulizers have been developed for delivery of small molecules in human patients, no tunable device has been purpose-built for targeted delivery of modern large molecule and temperature-sensitive therapeutics to mice. Mice are used most of all species in biomedical research and have the highest number of induced models for human-relevant diseases and transgene models. Regulatory approval of large molecule therapeutics, including antibody therapies and modified RNA highlight the need for quantifiable dose delivery in mice to model human delivery, proof-of-concept studies, efficacy, and dose-response. To this end, we developed and characterized a tunable nebulization system composed of an ultrasonic transducer equipped with a mesh nebulizer fitted with a silicone restrictor plate modification to control the nebulization rate. We have identified the elements of design that influence the most critical factors to targeted delivery to the deep lungs of BALB/c mice. By comparing an in silico model of the mouse lung with experimental data, we were able to optimize and confirm the targeted delivery of over 99% of the initial volume to the deep portions of the mouse lung. The resulting nebulizer system provides targeted lung delivery efficiency far exceeding conventional nebulizers preventing waste of expensive biologics and large molecules during proof-of-concept and pre-clinical experiments involving mice. (Word Count =207).

In vitro evaluation of the potential use of snake-derived peptides in the treatment of respiratory infections using inhalation therapy: A proof of concept study

Inhalation therapy using nebulisers is an attractive non-invasive route for drug delivery, particularly for the treatment of lung infections with anti-inflammatory and anti-microbial compounds. This study evaluated the suitability of three snake-derived peptides (termed Sn1b, SnE1 and SnE1-F), which we have recently shown have potent anti-inflammatory and bacteriostatic activities, for nebulisation using a vibrating mesh nebuliser (VMN). The effect of nebulisation on peptide concentration, stability and function were assessed, prior to progression to aerodynamic particle size distribution, and in vitro drug delivery in simulated adult spontaneous breathing and mechanical ventilated patient models. When nebulised, all three peptides exhibited similar functions to their non-nebulised counterparts and were found to be respirable during simulated mechanical ventilation. Based on the assessment of the droplet distributions of nebulised peptides using a Next Generation Impactor (NGI) demonstrated that if administered in vivo each peptide would likely be delivered to the lower airways. These data suggest that nebulisation using a VMN is a viable means of anti-microbial / anti-inflammatory peptide delivery targeting microbial respiratory infections, and possibly even systemic infections.

A path forward in the development of new aerosol drug delivery devices for pediatrics

Inhaled medications are widely accepted as being the optimal route for treating pediatric respiratory diseases, a leading cause of hospitalization and death. Despite jet nebulizers being the preferred inhalation device for neonates and infants, current devices face performance issues with most of the drug never reaching the target lung location. Previous work has aimed to improve pulmonary drug deposition, yet nebulizer efficiency remains low. The development of an inhalant therapy that is efficacious and safe for pediatrics depends on a well-designed delivery system and formulation. To accomplish this, the field needs to rethink the current practice of basing pediatric treatments on adult studies. The rapidly evolving pediatric patient (i.e. neonates to eighteen) needs to be considered because they are different from adults with respect to airway anatomy, breathing patterns, and adherence. Previous research approaches to improve deposition efficiency have been limited due to the complexity of combining physics, which drives aerosol transport and deposition, and biology, especially within the area of pediatrics. To address these critical knowledge gaps, we need a better understanding of how patient age and disease state affect deposition of aerosolized drugs. The complexity of the multiscale respiratory system makes scientific investigation very challenging. The authors have simplified the complex problem into five components with these three areas as ones to address first: how the aerosol is (i) generated in a medical device, (ii) delivered to the patient, and (iii) deposited inside the lung. In this review, we discuss the technological advances and innovations made from experiments, simulations, and predictive models in each of these areas. In addition, we discuss the impact on patient treatment efficacy and recommend a clinical direction, with a focus on pediatrics. In each area, a series of research questions are posed and steps for future research to improve efficacy in aerosol drug delivery are outlined.

Indian Guidelines on Nebulization Therapy

Inhalational therapy, today, happens to be the mainstay of treatment in obstructive airway diseases (OADs), such as asthma, chronic obstructive pulmonary disease (COPD), and is also in the present, used in a variety of other pulmonary and even non-pulmonary disorders. Hand-held inhalation devices may often be difficult to use, particularly for children, elderly, debilitated or distressed patients. Nebulization therapy emerges as a good option in these cases besides being useful in the home care, emergency room and critical care settings. With so many advancements taking place in nebulizer technology; availability of a plethora of drug formulations for its use, and the widening scope of this therapy; medical practitioners, respiratory therapists, and other health care personnel face the challenge of choosing appropriate inhalation devices and drug formulations, besides their rational application and use in different clinical situations. Adequate maintenance of nebulizer equipment including their disinfection and storage are the other relevant issues requiring guidance. Injudicious and improper use of nebulizers and their poor maintenance can sometimes lead to serious health hazards, nosocomial infections, transmission of infection, and other adverse outcomes. Thus, it is imperative to have a proper national guideline on nebulization practices to bridge the knowledge gaps amongst various health care personnel involved in this practice. It will also serve as an educational and scientific resource for healthcare professionals, as well as promote future research by identifying neglected and ignored areas in this field. Such comprehensive guidelines on this subject have not been available in the country and the only available proper international guidelines were released in 1997 which have not been updated for a noticeably long period of over two decades, though many changes and advancements have taken place in this technology in the recent past. Much of nebulization practices in the present may not be evidence-based and even some of these, the way they are currently used, may be ineffective or even harmful. Recognizing the knowledge deficit and paucity of guidelines on the usage of nebulizers in various settings such as inpatient, out-patient, emergency room, critical care, and domiciliary use in India in a wide variety of indications to standardize nebulization practices and to address many other related issues; National College of Chest Physicians (India), commissioned a National task force consisting of eminent experts in the field of Pulmonary Medicine from different backgrounds and different parts of the country to review the available evidence from the medical literature on the scientific principles and clinical practices of nebulization therapy and to formulate evidence-based guidelines on it. The guideline is based on all possible literature that could be explored with the best available evidence and incorporating expert opinions. To support the guideline with high-quality evidence, a systematic search of the electronic databases was performed to identify the relevant studies, position papers, consensus reports, and recommendations published. Rating of the level of the quality of evidence and the strength of recommendation was done using the GRADE system. Six topics were identified, each given to one group of experts comprising of advisors, chairpersons, convenor and members, and such six groups (A-F) were formed and the consensus recommendations of each group was included as a section in the guidelines (Sections I to VI). The topics included were: A. Introduction, basic principles and technical aspects of nebulization, types of equipment, their choice, use, and maintenance B. Nebulization therapy in obstructive airway diseases C. Nebulization therapy in the intensive care unit D. Use of various drugs (other than bronchodilators and inhaled corticosteroids) by nebulized route and miscellaneous uses of nebulization therapy E. Domiciliary/Home/Maintenance nebulization therapy; public & health care workers education, and F. Nebulization therapy in COVID-19 pandemic and in patients of other contagious viral respiratory infections (included later considering the crisis created due to COVID-19 pandemic). Various issues in different sections have been discussed in the form of questions, followed by point-wise evidence statements based on the existing knowledge, and recommendations have been formulated.

Assessment of High-Power Electronic Nicotine Delivery System as an Alternative Aerosol Device for Terbutaline Delivery

PURPOSE

The performance of new-generation high-power electronic nicotine delivery system (ENDS) for the administration of inhaled terbutaline was assessed.

METHODS

The formulation of e-liquid was carried out using terbutaline in combination with 1, 3- propanediol. Several terbutaline concentrations (from 0.3125 to 2.500 mg / mL) and power levels (from 15 to 35 W) were assessed using a box type ENDS. The respirable drug dose was determined using a Glass Twin Impinger and quantified by liquid chromatography coupled with a UV-detector. The Next Generation Impactor and the Dekati Low Pressure Impactor were used to measure the aerosol particle size distribution in drug mass. The results were compared with a jet nebulizer (Cirrus TM 2) similar to the usual clinical conditions (2 mL at [terbutaline] of 2.5 mg / mL).

RESULTS

The optimal conditions to maximize terbutaline delivery using ENDS are a drug concentration at 1 mg/mL, and a power level at 30 W, to reach a respirable dose of 8.73 ± 0.90 µg/puff. By contrast, during a 5 min nebulization, the respirable dose of terbutaline was 1040 ± 33 µg whatever the cascade impactors and the aerosol devices used. The mass median aerodynamic diameter (MMAD) remains similar for jet nebulizer and ENDS in the 1.74-2.07 µm range.

CONCLUSION

Compared to the jet nebulizer, a same respirable dose of terbutaline at the same range of aerosol size distribution was delivered by ENDS if 120 puffs were performed. The ENDS can be considered as an alternative aerosol device for terbutaline delivery.

In vitro delivery efficiencies of nebulizers for different breathing patterns

Background

Nebulizers are medical devices that deliver aerosolized medication directly to lungs to treat a variety of respiratory diseases. However, breathing patterns, respiration rates, airway diameters, and amounts of drugs delivered by nebulizers may be respiratory disease dependent.

Method

In this study, we developed a respiratory simulator consisting of an airway model, an artificial lung, a flow sensor, and an aerosol collecting filter. Various breathing patterns were generated using a linear actuator and an air cylinder. We tested six home nebulizers (jet (2), static (2), and vibrating mesh nebulizers (2)). Nebulizers were evaluated under two conditions, that is, for the duration of nebulization and at a constant output 1.3 mL using four breathing patterns, namely, the breathing pattern specified in ISO 27427:2013, normal adult, asthmatic, and COPD.

Results

One of the vibrating mesh nebulizers had the highest dose delivery efficiency. The drug delivery efficiencies of nebulizers were found to depend on breathing patterns.

Conclusion

We suggest a quantitative drug delivery efficiency evaluation method and calculation parameters that include considerations of constant outputs and residual volumes. The study shows output rates and breathing patterns should be considered when the drug delivery efficiencies of nebulizers are evaluated.

Contemporary Formulation Development for Inhaled Pharmaceuticals

Pulmonary delivery has gained increased interests over the past few decades. For respiratory conditions, targeted drug delivery directly to the site of action can achieve a high local concentration for efficacy with reduced systemic exposure and adverse effects. For systemic conditions, the unique physiology of the lung evolutionarily designed for rapid gaseous exchange presents an entry route for systemic drug delivery. Although the development of inhaled formulations has come a long way over the last few decades, many aspects of it remain to be elucidated. In particular, a reliable and well-understood method for in vitro-in vivo correlations remains to be established. With the rapid and ongoing advancement of technology, there is much potential to better utilise computational methods including different types of modelling and simulation approaches to support inhaled formulation development. This review intends to provide an introduction on some fundamental concepts in pulmonary drug delivery and inhaled formulation development followed by discussions on some challenges and opportunities in the translation of inhaled pharmaceuticals from preclinical studies to clinical development. The review concludes with some recent advancements in modelling and simulation approaches that could play an increasingly important role in modern formulation development of inhaled pharmaceuticals.

Aerosol Delivery of Dornase Alfa Generated by Jet and Mesh Nebulizers

Recent reports on mesh nebulizers suggest the possibility of stable nebulization of various therapeutic protein drugs. In this study, the in vitro performance and drug stability of jet and mesh nebulizers were examined for dornase alfa and compared with respect to their lung delivery efficiency in BALB/c mice. We compared four nebulizers: two jet nebulizers (PARI BOY SX with red and blue nozzles), a static mesh nebulizer (NE-U150), and a vibrating mesh nebulizer (NE-SM1). The enzymatic activity of dornase alfa was assessed using a kinetic fluorometric DNase activity assay. Both jet nebulizers had large residual volumes between 24% and 27%, while the volume of the NE-SM1 nebulizer was less than 2%. Evaluation of dornase alfa aerosols produced by the four nebulizers showed no overall loss of enzymatic activity or protein content and no increase in aggregation or degradation. The amount of dornase alfa delivered to the lungs was highest for the PARI BOY SX-red jet nebulizer. This result confirmed that aerosol droplet size is an important factor in determining the efficiency of dornase alfa delivery to the lungs. Further clinical studies and analysis are required before any conclusions can be drawn regarding the clinical safety and efficacy of these nebulizers.

Maintenance Therapy with Nebulizers in Patients with Stable COPD: Need for Reevaluation

Patients with stable COPD rely heavily on inhaled bronchodilators and corticosteroids to control symptoms, maximize quality of life, and avoid exacerbations and costly hospitalizations. These drugs are typically delivered by hand-held inhalers or nebulizers. The majority of patients are prescribed inhalers due to their perceived convenience, portability, and lower cost, relative to nebulizers. Unfortunately, poor inhaler technique compromises symptom relief in most of these patients. In contrast to one or two puffs through an inhaler, nebulizers deliver a drug over many breaths, through tidal breathing, and hence are more forgiving to poor inhalation technique. To what extent susceptibility to errors in their use may influence the relative effectiveness of these two types of inhalation device has received little attention in COPD research. In 2005, a systematic review of the literature concluded that nebulizers and inhalers are equally effective in patients who are adequately trained to use their inhalation device. This conclusion was based on two small clinical trials that only examined objective measures of lung function. Since then, additional studies have found that maintenance therapy administered by nebulizers could improve patients' reported feelings of symptom relief, quality of life, and satisfaction with treatment, compared to therapy administered by inhalers. Because it has been 15 years since the publication of the systematic review, in this article we summarize the results of studies that compared the effectiveness of inhalers with that of nebulizers in patients with stable COPD and discuss their implications for clinical practice and need for future research.

Comparison of Salbutamol Delivery Efficiency for Jet versus Mesh Nebulizer Using Mice

Recent reports using a breathing simulator system have suggested that mesh nebulizers provide more effective medication delivery than jet nebulizers. In this study, the performances of jet and mesh nebulizers were evaluated by comparing their aerosol drug delivery efficiencies in mice. We compared four home nebulizers: two jet nebulizers (PARI BOY SX with red and blue nozzles), a static mesh nebulizer (NE-U22), and a vibrating mesh nebulizer (NE-SM1). After mice were exposed to salbutamol aerosol, the levels of salbutamol in serum and lung were estimated by ELISA. The residual volume of salbutamol was the largest at 34.6% in PARI BOY SX, while the values for NE-U22 and NE-SM1 mesh nebulizers were each less than 1%. The salbutamol delivery efficiencies of NE-U22 and NE-SM1 were higher than that of PARI BOY SX, as the total delivered amounts of lung and serum were 39.9% and 141.7% as compared to PARI BOY SX, respectively. The delivery efficiency of the mesh nebulizer was better than that of the jet nebulizer. Although the jet nebulizer can generate smaller aerosol particles than the mesh nebulizer used in this study, the output rate of the jet nebulizer is low, resulting in lower salbutamol delivery efficiency. Therefore, clinical validation of the drug delivery efficiency according to nebulizer type is necessary to avoid overdose and reduced drug wastage.

In Vitro Characterization of the eFlow Closed System Nebulizer with Glycopyrrolate Inhalation Solution

Background: Glycopyrrolate administered by a novel, investigational eFlow^® Closed System (CS) nebulizer (eFlow CS) is being evaluated for the maintenance treatment of chronic obstructive pulmonary disease (COPD). The eFlow CS is a hand-held, vibrating membrane nebulizer optimized to deliver 1 mL of glycopyrrolate solution into the lung in <3 minutes. Clinical studies have shown improvements in lung function of subjects treated with nebulized glycopyrrolate.

Methods: The aerosol performance of the eFlow CS nebulizer was characterized by delivered dose, aerodynamic droplet size distribution and nebulization time. Simulated use nebulizer performance over 60 days was assessed by volume median diameter (VMD), nebulized amount, and nebulization time. Nebulization outputs were assayed to ensure adequate delivery of glycopyrrolate with an acceptable impurity profile. Aerosol condensates were analyzed for glycopyrrolate concentration and impurities by ultra-high-performance liquid chromatography and compared with non-nebulized samples.

Results: The mean mass median aerodynamic diameter, geometric standard deviation, and fine particle fraction were 3.7 μm, 1.7, and 72%, respectively, and independent of formulation strength (25 and 50 μg/mL). Delivered dose was 88% of the nominal dose for both formulation strengths. The mean delivered dose, assessed by breathing simulation, was 56.8% for 25 μg/mL and 62.6% for 50 μg/mL. Nebulization times were 1–2.5 minutes with no apparent increasing trend with use over a 60-day period. The nebulized amount showed no significant changes, whereas the VMD showed a slight, but not pharmaceutically relevant, increase (0.1–0.2 μm) after 60-day simulated use. Glycopyrrolate concentration and impurity levels of nebulized samples were statistically similar to those of non-nebulized samples.

Conclusion: The eFlow CS generates glycopyrrolate aerosols with high delivered dose, short treatment time, and small droplet size with narrow size distribution suitable for central and peripheral airway deposition. The unit dose vial mitigates medication misuse and ensures dose uniformity. Results support the use of glycopyrrolate/eFlow CS for the treatment of COPD.

Comparative Study on the Size Distributions, Respiratory Deposition, and Transport of Particles Generated from Commonly Used Medical Nebulizers

BACKGROUND

Medical nebulizers are widely and conveniently used to deliver medication to the lungs as an inhalable mist; however, the deposition of nebulized particles in the human respiratory system and the transport of the nebulized particles in the environment have not been studied in detail.

METHODS

Five medical nebulizers of three different types (constant output, breath enhanced, and dosimetric) were evaluated. The size distribution functions (SDFs) and respiratory deposition of the particles generated from the nebulizers were characterized. The SDFs were obtained with an aerodynamic particle sizer (APS; TSI, Inc., St. Paul) after data correction, and the respiratory deposition was calculated according to the model developed by the International Commission on Radiological Protection. The evaporation, Brownian diffusion, and convective movement are further calculated based on aerosol properties.

RESULTS AND CONCLUSIONS

The SDFs measured by the APS indicated that most of the generated particles were in the size range of 1-8 μm. The operating pressure and flow rate affected the number-based SDF of the nebulized particles. Although different values of mean aerodynamic diameter (MAD) were obtained for the nebulizers, the mass median aerodynamic diameter did not differ significantly from each other (between 4 and 5 μm). According to calculation, the deposition of particles in the head airways region accounted for the most of the particle mass collected by the respiratory system. Convective movement was the dominant mechanism for the transport of particles in the size ranges investigated. Relative humidity-dependent evaporation can significantly decrease the size of the emitted particles, resulting in a different respiratory deposition pattern such that the amount of particles deposited in the alveolar region is greatly enhanced. Appropriate protection from these particles should be considered for those persons for whom the medication is not intended (e.g., healthcare workers, family members).

Clinical Considerations in the Use of Inhalation Delivery Devices

Medications delivered through oral inhalation represent the cornerstone of pharmacotherapy for asthma and chronic obstructive pulmonary diseases. Several options exist as methods of delivering aerosols to the lung, including metered-dose inhalers, metered-dose inhalers attached to spacers or valved holding chambers, dry powder inhalers, and nebulizers. Delivery of aerosols to the lung is affected by numerous factors including characteristics of aerosol particles, patients’ ventilatory patterns, and physical condition of the lung. It has become increasingly clear that the device used to deliver the medication is an important factor in the extent of deposition and the ultimate therapeutic effect. Further, the same therapeutic agent may exhibit differing effects depending on which delivery device is used. Each inhalation device has specific instructions for use, and the techniques for use vary significantly among the available products. In each case, patients should be instructed and observed to ensure that they have the proper technique of use to achieve an optimal effect.

The function and performance of aqueous aerosol devices for inhalation therapy

OBJECTIVES

In this review paper, we explore the interaction between the functioning mechanism of different nebulizers and the physicochemical properties of the formulations for several types of devices, namely jet, ultrasonic and vibrating-mesh nebulizers; colliding and extruded jets; electrohydrodynamic mechanism; surface acoustic wave microfluidic atomization; and capillary aerosol generation.

KEY FINDINGS

Nebulization is the transformation of bulk liquids into droplets. For inhalation therapy, nebulizers are widely used to aerosolize aqueous systems, such as solutions and suspensions. The interaction between the functioning mechanism of different nebulizers and the physicochemical properties of the formulations plays a significant role in the performance of aerosol generation appropriate for pulmonary delivery. Certain types of nebulizers have consistently presented temperature increase during the nebulization event. Therefore, careful consideration should be given when evaluating thermo-labile drugs, such as protein therapeutics. We also present the general approaches for characterization of nebulizer formulations.

SUMMARY

In conclusion, the interplay between the dosage form (i.e. aqueous systems) and the specific type of device for aerosol generation determines the effectiveness of drug delivery in nebulization therapies, thus requiring extensive understanding and characterization.

Treatment of asthma exacerbations with the human-powered nebuliser: a randomised parallel-group clinical trial

Background:

Nebulisers aid the treatment of respiratory diseases, including asthma, but they require electricity and are often cost-prohibitive for low- and middle-income countries.

Aims:

The aim of this study was to compare a low-cost, human-powered nebuliser compressor with an electric nebuliser compressor for the treatment of mild to moderate asthma exacerbations in adults and children.

Methods:

This was a non-blinded, parallel-group, equivalence study, with 110 subjects between 6 and 65 years of age, conducted in the emergency department of a district hospital in Ilopango, El Salvador. Participants were assigned by random allocation to receive a 2.5-mg dose of salbutamol from the experimental human-powered nebuliser or the electric nebuliser control. All assigned participants completed treatment and were included in analysis. The study was not blinded as this was clinically unfeasible; however, data analysis was blinded.

Results:

The mean improvement in peak flow of the experimental and control groups was 37.5 (95% confidence interval (CI) 26.7–48.2) l/min and 38.7 (95% CI, 26.1–51.3) l/min, respectively, with a mean difference of 1.3 (95% CI, −15.1 to 17.7) l/min. The mean improvement in percent-expected peak flow for the experimental and control groups was 12.3% (95% CI, 9.1–15.5%) and 13.8% (95% CI, 9.8–17.9%), respectively, with a mean difference of 1.5% (95% CI, −3.6 to 6.6%).

Conclusions:

The human-powered nebuliser compressor is equivalent to a standard nebuliser compressor for the treatment of mild-to-moderate asthma. (Funded by the Opus Dean’s Fund, Marquette University College of Engineering; ClinicalTrials.gov NCT01795742.)

Characterization of a human powered nebulizer compressor for resource poor settings

Background

Respiratory disease accounts for three of the ten leading causes of death worldwide. Many of these diseases can be treated and diagnosed using a nebulizer. Nebulizers can also be used to safely and efficiently deliver vaccines. Unfortunately, commercially available nebulizers are not designed for use in regions of the world where lung disease is most prevalent: they are electricity-dependent, cost-prohibitive, and not built to be reliable in harsh operating conditions or under frequent use.

To overcome these limitations, the Human Powered Nebulizer compressor (HPN) was developed. The HPN does not require electricity; instead airflow is generated manually through a hand-crank or bicycle-style pedal system. A health care worker or other trained individual operates the device while the patient receives treatment.

This study demonstrates functional specifications of the HPN in comparison with a standard commercially available electric jet nebulizer compressor, the DeVilbiss Pulmo-Aide 5650D (Pulmo-Aide).

Methods

Pressure and flow characteristics were measured with a rotameter and pressure transducer, respectively. Volume nebulized by each compressor was determined by mass, and particle size distribution was determined via laser diffraction. The Hudson RCI Micro Mist nebulizer mouthpiece was used with both compressors.

Results

The pressure and flow generated by the HPN and Pulmo-Aide were: 15.17 psi and 10.5 L/min; and 14.65 psi and 11.2 L/min, respectively. The volume of liquid delivered by each was equivalent, 1.097 ± 0.107 mL (mean ± s.e.m., n = 13) for the HPN and 1.092 ± 0.116 mL for the Pulmo-Aide. The average particle size was also equivalent, 5.38 ± 0.040 micrometers (mean ± s.e.m., n = 7) and 5.40 ± 0.025 micrometers, respectively.

Conclusions

Based on these characteristics, the HPN’s performance is equivalent to a popular commercially available electric nebulizer compressor. The findings presented in this paper, combined with the results of two published clinical studies, suggest that the HPN could serve as an important diagnostic and therapeutic tool in the fight against global respiratory health challenges including: tuberculosis, chronic obstructive pulmonary disease, asthma, and lower respiratory infections.

Clinical experimentation with aerosol antibiotics: current and future methods of administration

Currently almost all antibiotics are administered by the intravenous route. Since several systems and situations require more efficient methods of administration, investigation and experimentation in drug design has produced local treatment modalities. Administration of antibiotics in aerosol form is one of the treatment methods of increasing interest. As the field of drug nanotechnology grows, new molecules have been produced and combined with aerosol production systems. In the current review, we discuss the efficiency of aerosol antibiotic studies along with aerosol production systems. The different parts of the aerosol antibiotic methodology are presented. Additionally, information regarding the drug molecules used is presented and future applications of this method are discussed.

Internal mouthpiece designs as a future perspective for enhanced aerosol deposition. Comparative results for aerosol chemotherapy and aerosol antibiotics

BACKGROUND

In an effort to identify factors producing a finest mist from Jet-Nebulizers we designed 2 mouthpieces with 4 different internal designs and 1-3 compartments.

MATERIALS AND METHODS

Ten different drugs previous used with their "ideal" combination of jet-nebulizer, residual-cup and loading were used. For each drug the mass median aerodynamic diameter size had been established along with their "ideal" combination.

RESULTS

For both mouthpiece, drug was the most important factor due the high F-values (Flarge=251.7, p<0.001 and Fsmall=60.1, p<0.001) produced. The design affected the droplet size but only for large mouthpiece (Flarge=5.99, p=0.001, Fsmall=1.72, p=0.178). Cross designs create the smallest droplets (2.271) so differing from the other designs whose mean droplets were greater and equal ranging between 2.39 and 2.447. The number of compartments in the two devices regarding the 10 drugs was found not statistically significant (p-values 0.768 and 0.532 respectively). Interaction effects between drugs and design were statistically significant for both devices (Flarge=8.87, p<0.001, Fsmall=5.33, p<0.001).

CONCLUSION

Based on our experiment we conclude that further improvement of the drugs intended for aerosol production is needed. In addition, the mouthpiece design and size play an important role in further enhancing the fine mist production and therefore further experimentation is needed.

New insights in the production of aerosol antibiotics. Evaluation of the optimal aerosol production system for ampicillin-sulbactam, meropenem, ceftazidime, cefepime and piperacillin-tazobactam

BACKGROUND

Several aerosol antibiotics are on the market and several others are currently being evaluated. Aim of the study was to evaluate the aerosol droplet size of five different antibiotics for future evaluation as an aerosol administration.

MATERIALS AND METHODS

The nebulizers Sunmist(®), Maxineb(®) and Invacare(®) were used in combination with four different "small <6 ml" residual cups and two "large <10 ml" with different loadings 2-4-6-8 ml (8 ml only for large residual cups) with five different antibiotic drugs (ampicilln-sulbactam, meropenem, ceftazidime, cefepime and piperacillin-tazobactam). The Mastersizer 2000 (Malvern) was used to evaluate the produced droplet size from each combination

RESULTS

Significant effect on the droplet size produced the different antibiotic (F=96.657, p<0.001) and the residual cup design (F=68.535, p<0.001) but not the different loading amount (p=0.127) and the nebulizer (p=0.715). Interactions effects were found significant only between antibiotic and residual cup (F=16.736, p<0.001). No second order interactions were found statistically significant.

CONCLUSION

Our results firstly indicate us indirectly that the chemical formulation of the drug is the main factor affecting the produced droplet size and secondly but closely the residual cup design.

Study of nebulization delivery of aerosolized fluorescent microspheres to the avian respiratory tract

This study investigated the delivery of an aerosol of monodisperse microspheres to the respiratory tract of birds following aerosol exposure. Adult domestic pigeons (Columbia livia domestica, n = 5 birds per timed treatment) were exposed to an aerosol of fluorescent 1.0 microm diameter carboxylate microspheres for 0.5, 1, 2, or 4 hr. During the aerosolization period, the birds were free-standing in a plexiglass treatment chamber and the aerosol was delivered using a commercial nebulizer. Immediately following aerosol exposure, the birds were euthanatized and the carcasses were intravenously infused with a modified paraformaldehyde/gluteraldehyde fixative. Evaluation of microsphere distribution was performed using a stereoscopic microscope with an epifluorescent module. The results from this study revealed that the amount of aerosolized particles delivered using a commercial nebulizer was proportional to exposure periods. Aerosol exposure periods of 0.5 hr or 1 hr did not result in a readily observable distribution of 1.0 microm fluorescent microspheres to the cranial thoracic, caudal thoracic, or abdominal air sac membranes. This was partly attributed to the relatively low concentration of the individual monodisperse microspheres in the aerosolized suspension. The 2- and 4-hr exposure periods resulted in readily observable deposition of the 1.0 mirom fluorescent microspheres in the cranial thoracic, caudal thoracic, or abdominal air sac membranes, with the 4-hr exposure period resulting in the greatest number of particles on the membrane surfaces. For each of the exposure periods, there was individual animal variation regarding the distribution and relative number of spheres deposited. This study demonstrates the widespread deposition of particles that had an aerodynamic equivalent diameter of approximately 1 microm and provides a better understanding of particle deposition efficiency within the respiratory system following aerosol exposure in birds.

Inhaled chemotherapy in lung cancer: future concept of nanomedicine

Regional chemotherapy was first used for lung cancer 30 years ago. Since then, new methods of drug delivery and pharmaceuticals have been investigated in vitro, and in animals and humans. An extensive review of drug delivery systems, pharmaceuticals, patient monitoring, methods of enhancing inhaled drug deposition, safety and efficacy, and also additional applications of inhaled chemotherapy and its advantages and disadvantages are presented. Regional chemotherapy to the lung parenchyma for lung cancer is feasible and efficient. Safety depends on the chemotherapy agent delivered to the lungs and is dose-dependent and time-dependent. Further evaluation is needed to provide data regarding early lung cancer stages, and whether regional chemotherapy can be used as neoadjuvant or adjuvant treatment. Finally, inhaled chemotherapy could one day be administered at home with fewer systemic adverse effects.

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.

In-vitro characterisation of the nebulised dose during non-invasive ventilation

Objectives

Non-invasive ventilation (NIV) with nebulised bronchodilators helps some patients to maintain effective ventilation. However, the position of the nebuliser in the ventilation circuit may affect lung delivery.

Methods

We placed the nebuliser proximal (A) and distal (B) to a breathing simulator in a standard NIV circuit with inspiratory (I) and expiratory (E) pressures of 20 and 5 cm H2O, 1 : 3 I : E ratio, 15 breaths/min and a tidal volume of 500 ml. Five milligrams of terbutaline solution was nebulised using an Aeroneb Pro (AERO) and a Sidestream (SIDE) nebuliser. The fate of the nebulised dose was determined and the aerodynamic droplet characteristics were measured using a cooled Next Generation Impactor.

Key findings

More terbutaline was entrained on the inhalation filter in position A than in position B (P &lt; 0.001) for both nebulisers. These amounts were greater (P &lt; 0.001) for AERO than SIDE due to a smaller (P &lt; 0.001) residual volume. The mean (SD) fine particle doses for AEROA, AEROB, SIDEA and SIDEB were 1.31 (0.2), 1.13 (0.14), 0.56 (0.03) and 0.39 (0.13) mg. These amounts from AEROA were significantly greater (P &lt; 0.001) than those of the other three methods.

Conclusions

The results highlight the differences between nebulisers and the influence on the placement of the nebuliser in the NIV circuit.

Current therapies and technological advances in aqueous aerosol drug delivery

Recent advances in aerosolization technology have led to renewed interest in pulmonary delivery of a variety of drugs. Pressurized metered dose inhalers (pMDIs) and dry powder inhalers (DPIs) have experienced success in recent years; however, many limitations are presented by formulation difficulties, inefficient delivery, and complex device designs. Simplification of the formulation process as well as adaptability of new devices has led many in the pharmaceutical industry to reconsider aerosolization in an aqueous carrier. In the acute care setting, breath-enhanced air-jet nebulizers are controlling and minimizing the amount of wasted medication, while producing a high percentage of respirable droplets. Vibrating mesh nebulizers offer advantages in higher respirable fractions (RFs) and slower velocity aerosols when compared with air-jet nebulizers. Vibrating mesh nebulizers incorporating formulation and patient adaptive components provide improvements to continuous nebulization technology by generating aerosol only when it is most likely to reach the deep lung. Novel innovations in generation of liquid aerosols are now being adapted for propellant-free pulmonary drug delivery to achieve unprecedented control over dose delivered and are leading the way for the adaptation of systemic drugs for delivery via the pulmonary route. Devices designed for the metered dose delivery of insulin, morphine, sildenafil, triptans, and various peptides are all currently under investigation for pulmonary delivery to treat nonrespiratory diseases. Although these devices are currently still in clinical testing (with the exception of the Respimat), metered dose liquid inhalers (MDLIs) have already shown superior outcomes to current pulmonary and systemic delivery methods.

New treatment options in allergic rhinitis: patient considerations and the role of ciclesonide

Allergic rhinitis (AR) is a chronic inflammatory respiratory disease affecting 5%-50% of the worldwide population and its prevalence is increasing (Herman 2007). In addition, AR is associated with asthma and other co-morbidities such as conjunctivitis and sinusitis. The main symptoms are nasal congestion, rhinorrea, sneezing, itching, and post-nasal drainage induced after allergen exposure by an IgE-mediated inflammation of the membranes lining the nose. AR is not a life-threatening disease, but it has been shown to have a significant impact on quality of life. The Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines propose a classification of AR in intermittent and persistent, each graded as mild or moderate-severe, and provide a stepwise approach to the treatment. Inhaled steroids and antihistamine are the main tools in AR therapy but more safe and effective drugs are, however, needed. Inhaled steroid ciclesonide appears to be safe and effective.

Evaluation of Nebulizer Performance under Various Humidity Conditions

Jet nebulizers are a drug delivery tool commonly used for treating respiratory diseases. When a nebulizer generates aerosols, the rate at which droplets evaporate depends on humidity conditions around the nebulizer outlet. Because the relative humidity (RH) of the air affects the evaporation rate, the aerosol distribution and drug delivery dose is also affected by RH. Four nebulizers were chosen for comparison in this study: PARI LC Plus (PARI Respiratory Equipment, Inc., Midlothian, VA), SideStream (Medic-Aid Ltd., UK), VixOne (Westmed, Inc., Tucson, AZ), and Micromist (Hudson Respiratory Care Inc., Temecula, CA). Two different formulations were used: albuterol (liquid solution) and budesonide (suspension). Particle distribution (mass median aerodynamic diameter [MMAD] and geometric standard deviation [GSD]), nebulizer efficiency (total efficiency and respirable fraction [RF] efficiency for particles less than 4.7 microm), and dead volume (the amount of solution remaining after nebulization) were compared at the RH of 5%, 50%, and 80%. Our results showed that the MMAD increased (p value varied from <0.001 to 0.016) with the increase in RH, except for with the VixOne unit with albuterol (p = 0.24). The MMAD from the budesonide always appeared higher than from the albuterol. The RF (and thus, the inhalation dose) was lower with a higher RH. Except for the PARI LC Plus with budesonide, the RF decreased approximately 15-27% when the RH rose from 5% to 50%. For the PARI LC Plus nebulizer, the lower dead volume (0.22 mL) with higher residual drugs (62.3% of total drug) was obtained at an RH of 5% comparing the RH of 50% and 80% because of the unit's unique design.

Nebuliser hood compared to mask in wheezy infants: aerosol therapy without tears!

BACKGROUND

Small volume nebulisers (SVNs) with masks commonly provide aerosol therapy for infants with lung diseases. However, infants and toddlers are often disturbed by and thus reject masks.

AIMS

To compare the lung deposition efficiency of the "usual" SVN aerosol mask and a prototype hood attached to an SVN. The advantage of the hood is that no mask is needed and medication can readily be administered during sleep.

METHODS

99mTc salbutamol solution was administered at random by SVN plus mask or hood to 14 wheezy infants (mean age 8 (SD 5) months). The dose and distribution of salbutamol were evaluated using gamma scintigraphy. Clinical response, tolerability by the infants, and parent preference were also compared.

RESULTS

Mean total lung deposition was 2.6% with the hood and 2.4% with the mask (p > 0.05). Variability with the mask was greater than with the hood (coefficient of variation (CoV) 54% v 39%). Both treatments provided similar clinical benefit and side effects as reflected in improved oxygen saturation, reduced respiratory frequency, and increased heart rate. Infants accepted the hood better than the mask and there was a positive correlation between poor acceptance and upper airways and stomach deposition for both treatment modalities. Parents preferred the hood treatments.

CONCLUSIONS

Aerosol therapy by hood is as efficient as by mask but provides a better therapeutic index. It is much better tolerated by infants and preferred by parents. Hood nebulisation is a simple and patient friendly mode of aerosol therapy in wheezy infants.

Importance of drug delivery system in steroid aerosol therapy via nebulizer

Aim of our study was to evaluate if the type of nebulizer can influence the effects of steroid aerosol therapy. We considered 27 asthmatics allergic to grasses with FEV1<80% of the predictive value or methacholine PD20 FEV1<750 mcg. The patients were divided into three groups in relation to the type of nebulizer they used and treated 9 weeks by aerosol therapy with beclomethasone dipropionate bid (800 mcg). Respect to the values recorded at the beginning and at the end of the therapy we found different variations of spirometric indeces and PD20 values among the three groups. We can conclude that the type of nebulizer influences steroid aerosol therapy and, particularly, jet nebulizers seem more efficient than ultrasonic nebulizers.

Treatment of acute severe asthma and chronic obstructive pulmonary disease in Danish hospitals. Do national recommendations improve on the quality of the treatment?

Studies have demonstrated suboptimal treatment of acute severe asthma and chronic obstructive pulmonary disease (COPD). We examined the quality of treatment in Denmark and the effect of intervention, by publication of recommendations for standardised treatment. All 70 hospitals in Denmark with emergency facilities participated in a telephone questionnaire, examining treatment behaviours among house officers. The survey was repeated 3 years later, after publication of national recommendations for treatment of acute exacerbations of asthma and COPD. The response rate in both surveys was 100%. An insufficient handling of nebulisers, a huge variation in the delivered dose of bronchodilators and a suboptimal use of corticosteroids was found. A significant trend towards more liberate use of oxygen was seen in both asthma (3.2 l min(-1) versus 4.8 l min(-1), P<0.001) and COPD (1.5 l min(-1) versus 1.9 l min(-1), P = 0.047). Further, a huge difference in treatment behaviours was revealed from this survey The knowledge among house officers of basic principles of treatment was insufficient. Treatment behaviour was only moderately affected by national publication of detailed recommendations for treatment. This study indicates a need for implementing tools for quality control.

Improving drug delivery from medical nebulizers: the effects of increased nebulizer flow rates and reservoirs

Drug delivery from jet nebulizers can be considered in terms of the dose inhaled and the respirability of that dose. It is proposed that dose respirability and dose per breath can be controlled through specification of the driving gas flowrate, and that the dose inhaled per breath can also be increased through the use of nebulizer reservoirs. When a Hudson Micromist nebulizer was used and assessments of respirability were made utilizing phase Doppler interferometry, it was noted that the portion of the spray mass in droplet sizes of <or=5 microm (general respirability) and in droplet sizes of <or=3 microm (deep lung respirability) increased linearly with gas flowrate for both tank air and helium-oxygen (70/30). Drug mass in the 2-6 microm range (tracheobronchial respirability) peaked at air flowrates of 8-10 LPM and decreased slightly for higher flowrates. Two portable compressors provided respirabilities similar to tank air at the same flowrates. Changing the nebulizer flowrate did not affect the ratio of the inhaled dose to the dose expelled by exhalation when a typical breathing pattern was simulated. A version of the Micromist with an attached reservoir (the Hudson AeroTee) provided a higher dose per breath to the patient and a higher total dose for the same treatment time by conserving the aerosol generated during exhalation. The inhaled dose increased approximately 28% when compared to a standard Micromist, despite significant deposition in the reservoir bag. Nebulizer reservoirs could be used to attain higher doses or to more efficiently utilize expensive medications.

The equivalence of compressor pressure-flow relationships with respect to jet nebulizer aerosolization characteristics

Manufacturers of aerosolized medications, approved by the Food and Drug Administration, specify the nebulizer(s) and compressor to be used with their product, in an attempt to achieve efficacy comparable to that obtained in the clinical trials. The need to limit the compressor to that used in the trials has not been investigated in detail. We suggest a technique to determine the equivalency of different compressors such that a chosen nebulizer's performance is not significantly altered. Aerosol particle size (MMD) was measured with a laser; compressor flow and pressure were measured with a mass flow meter and pressure gauge, respectively. For all models of nebulizer, increased flow or driving pressure caused a decrease in aerosol MMD. The flow resistance of nebulizer models varied, and the flow output of compressors decreased as imposed nebulizer resistance increased. However, for any specific compressor-nebulizer combination there is a unique flow and pressure, and the nebulizer generates a given MMD. We demonstrate methods to choose alternate compressors that may be used to drive a nebulizer and yet keep the nebulizer's MMD and performance within predetermined limits. Once an acceptable range of variance in a nebulizer's MMD is defined, alternate compressors may be safely chosen. We recommend that these techniques be used by manufacturers of medications and of compressors to safely determine the acceptability of several rather than a single model compressor to drive a chosen nebulizer. The techniques assure consistency of the nebulizer's clinically demonstrated performance characteristics.

The choice of compressor effects the aerosol parameters and the delivery of tobramycin from a single model nebulizer

Recent U.S. Phase III trials of the aerosolized delivery of tobramycin to cystic fibrosis (CF) patients demonstrated a significant improvement in pulmonary function and in sputum bacterial density. These trials used the Pari LC Plus nebulizer and DeVilbiss Pulmo-Aide compressor. This compressor is not generally available in Europe, and its power requirements do not match the European power supply. Thus alternate compressors were evaluated, using the LC Plus nebulizer, in preparation for European clinical trials. Aerosol particle size distribution, nebulization time (min), and the respirable dose of tobramycin (mg within 1-5 mu) were obtained for seven compressor models. The respirable quantity delivered by each of the European compressors (240 Volts, 50 Hz) was compared to the LC Plus and PulmoAide compressor (120 Volts, at 60 Hz). The U.S. system delivered 71.4 mg of the 300 mg instilled dose within the respirable range; using the European compressors, between 63.0 and 74.8 mg was delivered. With a 97% confidence that the delivered tobramycin was within 20% of the standard, we conclude that the SystAm 23ST, MedicAid CR50 and CR60, Pari Master and the Pari Boy compressors are equivalent to the U.S. standard; the Hercules and the SystAm 26ST compressors were not statistically equivalent to the standard. Using the LC Plus nebulizer, five European compressors delivered doses of TOBI that are similar to the doses delivered by the DeVilbiss PulmoAide compressors, and thus may be expected to produce clinical results similar to those of the U.S. trials.

Effects of repetitive use and cleaning techniques of disposable jet nebulizers on aerosol generation

STUDY OBJECTIVE

Patients with cystic fibrosis use disposable jet nebulizers for the self-administration of antibiotics, DNase, and bronchodilators several times per day. Most patients elect to reuse their disposable nebulizers. The purpose of this study was to determine if significant changes in particle size distribution or output (mL/min) occurred with reuse.

DESIGN

In vitro studies were performed using four disposable models and one durable jet nebulizer for up to 100 runs; measurements of particle size and output were obtained at 10 run intervals, using saline solution alone, tobramycin, gentamicin, or a mixture of albuterol and cromolyn. Particle size determinations were made with a laser diffraction analyzer.

RESULTS

There was no significant difference between the baseline performance of the four disposable models and the durable Pari LC, when measuring particle size distribution of the aerosol; the Pari LC had an output rate two to three times higher than the four disposable models. For each of the four solutes tested, there was no clinically significant change in performance for up to 100 cycles, when the nebulizers were properly cleaned between uses. Unwashed units containing tobramycin started to fail by 40 runs.

CONCLUSIONS

When properly maintained, there was no trend of deterioration of performance with repeated use of disposable nebulizers. Microbial contamination was not addressed in this study and must be considered prior to recommendations for the reuse of disposable nebulizers.

Home nebulizer use among patients with cystic fibrosis

OBJECTIVE

To describe current patterns of home nebulizer use among patients with cystic fibrosis.

STUDY DESIGN

A population-based survey of home nebulizer practices among 227 patients with cystic fibrosis using nebulizers from 1993 to 1994 (Objective 1), and a prospective study of "typical" home use, including testing of performance and bacterial cultures in nebulizers after use, completed by 36 subjects (Objective 2).

RESULTS

Objective 1: 85% of subjects reported using jet and 8% ultrasonic nebulizers (categories not mutually exclusive); 15% used unknown brands. Most jet nebulizers were disposable models, which were used for > 14 days by more than half the subjects. Mixing of medications in a single treatment (other than cromolyn and a bronchodilator) was reported by 28% of patients. Objective 2: no apparent deterioration in aerosol particle size or output rate of returned nebulizers compared with new units was observed. Staphylococcus aureus was cultured from 55% and Pseudomonas aeruginosa from 35% of returned nebulizers. Concordance between nebulizer and sputum cultures was poor.

CONCLUSIONS

Although not generally tested for reusability, disposable nebulizers are generally used by patients for long periods. Medication mixing is common, although its effects on aerosol properties are unknown. Cystic fibrosis respiratory pathogens are frequently isolated from used nebulizers. Patient guidelines for home nebulizer use need to be established.

Is high-dose fluticasone propionate via a metered-dose inhaler and Volumatic as efficacious as nebulized budesonide in adult asthmatics?

The efficacy and tolerability of fluticasone propionate (FP) 2 mg daily via a metered-dose inhaler and Volumatic (Glaxo Wellcome) spacer device was compared with nebulized budesonide (nBUD), 2 and 4 mg daily, in a multi-centre, open-label, cross-over study of adult asthmatics. Patients received, in random order, either 4 weeks of treatment with FP followed by 4 weeks of treatment with nBUD, or vice versa, with an intervening 4 week 'wash-out' period between treatments. Thirty patients completed the study, of whom 24 were evaluable. In terms of the primary efficacy parameter, change in mean morning peak expiratory flow (PEF) (l min-1) from baseline to the fourth week of each treatment period, FP was more effective than nBUD [mean difference (FP-nBUD) 21.1 l min-1, P = 0.007, 95% CI (6.5, 35.7)]. Sub-group analysis demonstrated FP to be superior to the 4 mg nBUD [mean treatment difference (FP-nBUD) 42.9 l min-1, P = 0.026, 95% CI (7.1, 78.8)] and at least as efficacious as the 2 mg nBUD sub-group [mean treatment difference (FP-nBUD) 10.2 l min-1, P = 0.211, 95% CI (-6.5, 26.9)]. Furthermore, larger reductions in diurnal variation were observed during FP treatment [mean treatment difference (FP-nBUD) -4.4 percentage points, P = 0.028, 95% CI (-8.4, -0.5)]. There was no significant difference between the treatments for the proportion of symptom-free 24 h periods. Of those expressing a preference, significantly more patients found FP via a metered-dose inhaler and spacer device both easier to administer (78%, P = 0.007) and more convenient to take (76%, P = 0.008) than nebulized budesonide. In addition, cost per patient analysis showed that nebulized budesonide was from 1.7 to 3.5 times more expensive than FP.

Running a domiciliary nebuliser service

A nebuliser service should be provided locally, according to local needs. It should be centralised and administered by a designated consultant or consultants and written guidelines should be provided for medical and para-medical staff. The service should: (1) provide compressor/nebuliser units suitable for the prescribed treatment, (2) provide a system for equipment replacement, repair and maintenance, and (3) show patients how to use the equipment and give them comprehensive written instructions.