Recent advances in aerosol therapy for children with asthma

State-of-the-Art Review of The Application and Development of Various Methods of Aerosol Therapy

Aerosol therapy is a rapidly developing field of science. Due to a number of advantages, the administration of drugs to the body with the use of aerosol therapy is becoming more and more popular. Spraying drugs into the patient's lungs has a significant advantage over other methods of administering drugs to the body, including injection and oral methods. In order to conduct proper and effective aerosol therapy, it is necessary to become familiar with the basic principles and applications of aerosol therapy under various conditions. The effectiveness of inhalation depends on many factors, but most of all on: the physicochemical properties of the sprayed system, the design of the medical inhaler and its correct application, the dynamics of inhalation (i.e. the frequency of breathing and the volume of inhaled air). It is worth emphasizing that respiratory system diseases are one of the most frequently occurring and fastest growing diseases in the world. Accordingly, in recent years, a significant increase in the number of new spraying devices and pharmaceutical drugs for spraying has appeared on the market. It should also be remembered that the process of spraying a liquid is a complicated and complex process, and its efficiency is very often characterized by the use of micro- and macro parameters (including average droplet diameters or the spectrum of droplet diameter distribution). In order to determine the effectiveness of the atomization process and in the delivery of drugs to the patient's respiratory tract, the analysis of the size of the generated aerosol droplets is most often performed. Based on the proposed literature review, it has been shown that many papers dealt with the issues related to aerosol therapy, the selection of an appropriate spraying device, the possibility of modifying the spraying devices in order to increase the effectiveness of inhalation, and the possibility of occurrence of certain discrepancies resulting from the use of various measurement methods to determine the characteristics of the generated aerosol. The literature review presented in the paper was prepared in order to better understand the spraying process. Moreover, it can be helpful in choosing the right medical inhaler for a given liquid with specific rheological properties. The experimental data contained in this study are of great cognitive importance and may be of interest to entities involved in pharmaceutical product engineering (in particular in the case of the production of drugs containing liquids with complex rheological properties).

Mask Use with Spacers/Valved Holding Chambers and Metered Dose Inhalers among Children with Asthma

Inhaler misuse is highly prevalent and associated with high morbidity and costs. For metered dose inhalers, proper use can be supported with devices such as spacers/valved holding chambers (VHCs) and masks to effectively deliver inhaled medication to the lungs. However, guidelines are vague about which children with asthma should use spacers/VHCs with masks to deliver medication from metered dose inhalers as well as when they should transition to spacers/VHCs with mouthpieces. In this paper, we provide a focused review of the evidence for mask use, highlighting unclear and conflicting information in guidelines and studies. We synthesize the differences in recommendations and practice. Based on these findings, we call for future research to determine the appropriate age and necessary skills for transitioning children from using metered dose inhalers with spacers/VHCs and masks to using spacers/VHCs and mouthpieces. Guidelines about mask use should be standardized to help ensure optimal medical delivery for patients, provide consistent inhaler prescriptions and education across settings, and support team-based care to help lower pediatric asthma morbidity and costs.

High-Efficiency Dry Powder Aerosol Delivery to Children: Review and Application of New Technologies

While dry powder aerosol formulations offer a number of advantages, their use in children is often limited due to poor lung delivery efficiency and difficulties with consistent dry powder inhaler (DPI) usage. Both of these challenges can be attributed to the typical use of adult devices in pediatric subjects and a lack of pediatric-specific DPI development. In contrast, a number of technologies have recently been developed or progressed that can substantially improve the efficiency and reproducibility of DPI use in children including: (i) nose-to-lung administration with small particles, (ii) active positive-pressure devices, (iii) structures to reduce turbulence and jet momentum, and (iv) highly dispersible excipient enhanced growth particle formulations. In this study, these technologies and their recent development are first reviewed in depth. A case study is then considered in which these technologies are simultaneously applied in order to enable the nose-to-lung administration of dry powder aerosol to children with cystic fibrosis (CF). Using a combination of computational fluid dynamics (CFD) analysis and realistic in vitro experiments, device performance, aerosol size increases and lung delivery efficiency are considered for pediatric-CF subjects in the age ranges of 2-3, 5-6 and 9-10 years old. Results indicate that a new 3D rod array structure significantly improves performance of a nasal cannula reducing interface loss by a factor of 1.5-fold and produces a device emitted mass median aerodynamic diameter (MMAD) of 1.67 μm. For all ages considered, approximately 70% of the loaded dose reaches the lower lung beyond the lobar bronchi. Moreover, significant and rapid size increase of the aerosol is observed beyond the larynx and illustrates the potential for targeting lower airway deposition. In conclusion, concurrent CFD and realistic in vitro analysis indicates that a combination of multiple new technologies can be implemented to overcome obstacles that currently limit the use of DPIs in children as young as two years of age.

CFD Guided Optimization of Nose-to-Lung Aerosol Delivery in Adults: Effects of Inhalation Waveforms and Synchronized Aerosol Delivery

PURPOSE

The objective of this study was to optimize nose-to-lung aerosol delivery in an adult upper airway model using computational fluid dynamics (CFD) simulations in order to guide subsequent human subject aerosol delivery experiments.

METHODS

A CFD model was developed that included a new high-flow nasal cannula (HFNC) and pharmaceutical aerosol delivery unit, nasal cannula interface, and adult upper airway geometry. Aerosol deposition predictions in the system were validated with existing and new experimental results. The validated CFD model was then used to explore aerosol delivery parameters related to synchronizing aerosol generation with inhalation and inhalation flow rate.

RESULTS

The low volume of the new HFNC unit minimized aerosol transit time (0.2 s) and aerosol bolus spread (0.1 s) enabling effective synchronization of aerosol generation with inhalation. For aerosol delivery correctly synchronized with inhalation, a small particle excipient-enhanced growth delivery strategy reduced nasal cannula and nasal depositional losses each by an order of magnitude and enabled ~80% of the nebulized dose to reach the lungs. Surprisingly, nasal deposition was not sensitive to inhalation flow rate due to use of a nasal cannula interface with co-flow inhaled air and the small initial particle size.

CONCLUSIONS

The combination of correct aerosol synchronization and small particle size enabled high efficiency nose-to-lung aerosol delivery in adults, which was not sensitive to inhalation flow rate.

Commercial valved spacers versus home-made spacers for delivering bronchodilator therapy in pediatric acute asthma: a cost-effectiveness analysis

Objective: Although valved spacers are the preferred method for administering metered-dose inhaler bronchodilators such as albuterol in pediatric acute asthma, their high cost and their lack of availability have limited their use, especially in low- and middle-income countries (LMICs). Because of this, it is a common practice to use home-made spacers, although a formal analysis evaluating their cost-effectiveness is lacking. Therefore, the objective of this study was to analyze the cost-effectiveness of home-made spacers compared to commercial valved spacers for delivering bronchodilator therapy in pediatric acute asthma.Methods: A decision-analysis model was used to estimate health outcomes and costs of a simulated cohort of pediatric patients treated for acute asthma. Effectiveness parameters were obtained from a systematic review of the literature. Cost data were obtained from hospital bills and from the national manual of drug prices in Colombia. The study was carried out from the perspective of the national healthcare system in Colombia, a middle-income country (MIC). The main outcome of the model was avoidance of hospital admission.Results: Base-case analysis showed that compared to commercial valved spacers, administering bronchodilators with home-made spacers results in lower overall treatment costs (US$126.75 vs. US$128.59 average cost per patient) without a significant difference in the probability of hospitalization avoided (0.8500 vs. 0.8500).Conclusions: The present study shows that in Colombia, an MIC, compared with commercial valved spacers, the use of home-made spacers for administering bronchodilator therapy is more cost-effective because it yields a similar probability of hospital admission at lower overall treatment costs.

Development of an Inline Dry Powder Inhaler for Oral or Trans-Nasal Aerosol Administration to Children

Background: Dry powder inhalers (DPIs) offer a number of advantages, such as rapid delivery of high-dose inhaled medications; however, DPI use in children is often avoided due to low lung delivery efficiency and difficulty in operating the device. The objective of this study was to develop a high-efficiency inline DPI for administering aerosol therapy to children with the option of using either an oral or trans-nasal approach. Methods: An inline DPI was developed that consisted of hollow inlet and outlet capillaries, a powder chamber, and a nasal or oral interface. A ventilation bag or compressed air was used to actuate the device and simultaneously provide a full deep inspiration consistent with a 5-year-old child. The powder chamber was partially filled with a model spray-dried excipient enhanced growth powder formulation with a mass of 10 mg. Device aerosolization was characterized with cascade impaction, and aerosol transmissions through oral and nasal in vitro models were assessed. Results: Best device performance was achieved when all actuation air passed through the powder chamber (no bypass flow) resulting in an aerosol mean mass median aerodynamic diameter (MMAD) <1.75 μm and a fine particle fraction (<5 μm) ≥90% based on emitted dose. Actuation with the ventilation bag enabled lung delivery efficiency through the nasal and oral interfaces to a tracheal filter of 60% or greater, based on loaded dose. In both oral and nose-to-lung (N2L) administrations, extrathoracic depositional losses were <10%. Conclusion: In conclusion, this study has proposed and initially developed an efficient inline DPI for delivering spray-dried formulations to children using positive pressure operation. Actuation of the device with positive pressure enabled effective N2L aerosol administration with a DPI, which may be beneficial for subjects who are too young to use a mouthpiece or to simultaneously treat the nasal and lung airways of older children.

The thermostated medical jet nebulizer: Aerosol characteristics

The sudden expansion of gas at the outlet of the jet (pneumatic) nebulizer significantly reduces the temperature of the solution, which may provoke bronchospasm, therefore it is recommended to use modern pneumatic inhalers equipped with a thermostat or a universal thermal attachment that allow to obtain a higher temperature aerosol, i.e. thermo-aerosol. The research was carried out for model Newtonian fluids. The droplet diameters of the aerosol spray were investigated using a Spraytec aerosol particle size measurement system. Analysis of the obtained results showed that the increase in solution viscosity caused a decrease in mean droplet diameters and prolonged nebulization time. The analysis of experimental data made it possible to propose a correlation equation describing the mean diameter of the droplets depending on the properties of the liquid and the flow conditions in the thermostated medical nebulizer. The obtained data contributes to a better understanding of the complex liquid atomisation process and can be helpful in the design of medical nebulizers and pharmaceutical preparations.

Targeting inhaled aerosol delivery to upper airways in children: Insight from computational fluid dynamics (CFD)

Despite the prevalence of inhalation therapy in the treatment of pediatric respiratory disorders, most prominently asthma, the fraction of inhaled drugs reaching the lungs for maximal efficacy remains adversely low. By and large drug delivery devices and their inhalation guidelines are typically derived from adult studies with child dosages adapted according to body weight. While it has long been recognized that physiological (e.g. airway sizes, breathing maneuvers) and physical transport (e.g. aerosol dynamics) characteristics are critical in governing deposition outcomes, such knowledge has yet to be extensively adapted to younger populations. Motivated by such shortcomings, the present work leverages in a first step in silico computational fluid dynamics (CFD) to explore opportunities for augmenting aerosol deposition in children based on respiratory physiological and physical transport determinants. Using an idealized, anatomically-faithful upper airway geometry, airflow and aerosol motion are simulated as a function of age, spanning a five year old to an adult. Breathing conditions mimic realistic age-specific inhalation maneuvers representative of Dry Powder Inhalers (DPI) and nebulizer inhalation. Our findings point to the existence of a single dimensionless curve governing deposition in the conductive airways via the dimensionless Stokes number (Stk). Most significantly, we uncover the existence of a distinct deposition peak irrespective of age. For the DPI simulations, this peak (∼ 80%) occurs at Stk ≈ 0.06 whereas for nebulizer simulations, the corresponding peak (∼ 45%) occurs in the range of Stk between 0.03-0.04. Such dimensionless findings hence translate to an optimal window of micron-sized aerosols that evolves with age and varies with inhalation device. The existence of such deposition optima advocates revisiting design guidelines for optimizing deposition outcomes in pediatric inhalation therapy.

Scintigraphic Assessment of Deposition of Radiolabeled Fluticasone Delivered from a Nebulizer and Metered Dose Inhaler in 10 Healthy Dogs

Background

Aerosolized medications are increasingly being used to treat respiratory diseases in dogs. No previous studies assessing respiratory tract deposition of radiolabeled aerosols have been performed in conscious dogs.

Hypothesis/Objectives

Assess respiratory tract deposition of radiolabeled, inhalant corticosteroid (fluticasone propionate labeled with ^99mTc) delivered from a nebulizer and metered dose inhaler (MDI) to healthy dogs.

Animals

Ten healthy Foxhounds.

Methods

Prospective, randomized, cross‐over pilot study. Initial inhalation method (nebulizer or MDI) was randomly assigned. Treatments were crossed over after a 7‐day washout period. Treatments initially were performed using sedation. Dogs were imaged using 2‐dimensional planar scintigraphy, with respiratory tract deposition quantified by manual region‐of‐interest analysis. Deposition calculated as percentage of delivered dose. Six of 10 dogs were randomly selected and reassessed without sedation.

Results

Inhalation method had significant effect on respiratory tract deposition (P = 0.027). Higher deposition was achieved by nebulization with mean deposition of 4.2% (standard deviation [SD], 1.4%; range, 1.9–6.1%); whereas MDI treatment achieved a mean of 2.3% (SD, 1.4%; range, 0.2–4.2%). Nebulization achieved higher respiratory tract deposition than MDI in 7 of 10 dogs. No statistical difference (P = 0.68) was found between mean respiratory tract deposition achieved in dogs when unsedated (3.8%; SD, 1.5%) or sedated (3.6%; SD, 1.7%).

Conclusions and Clinical Importance

Study confirms respiratory tract deposition of inhalant medications delivered from a nebulizer and MDI in healthy dogs, breathing tidally with and without sedation. Respiratory tract deposition in these dogs was low compared to reported deposition in adult humans, but similar to reported deposition in children.

Drug delivery interfaces: A way to optimize inhalation therapy in spontaneously breathing children

There are several different types of drug delivery interfaces available on the market. Using the right interface for aerosol drug delivery to children is essential for effective inhalation therapy. However, clinicians usually focus on selecting the right drug-device combination and often overlook the importance of interface selection that lead to suboptimal drug delivery and therapeutic response in neonates and pediatrics. Therefore, it is necessary to critically assess each interface and understand its advantage and disadvantages in aerosol drug delivery to this patient population. The purpose of this paper is to provide a critical assessment of drug delivery interfaces used for the treatment of children with pulmonary diseases by emphasizing advantages and problems associated with their use during inhalation therapy.

Pressurised metered dose inhaler-spacer technique in young children improves with video instruction

The importance of good device technique to maximise delivery of aerosolised medications is widely recognised. Pressurised metered dose inhaler (pMDI)-spacer technique was investigated in 122 children, aged 2-7 years, with asthma. Eight individual steps of device technique were evaluated before and after viewing an instructional video for correct device technique. Video measurements were repeated every three months for nine months. Device technique improved directly after video instruction at the baseline study visit (p < 0.001) but had no immediate effect at subsequent visits. Additionally, pMDI-spacer technique improved with successive visits over one year for the group overall as evidenced by increases in the proportion of children scoring maximal (p = 0.02) and near-maximal (p = 0.04) scores.

CONCLUSION

Repeated video instruction over time improves inhaler technique in young children.

WHAT IS KNOWN

• Correct device technique is considered essential for sufficient delivery of inhaled medication. • Poor inhaler use is common in young asthmatic children using pressurised metered dose inhalers and spacers. What is New: • Video instruction could be used as a strategy to improve device technique in young children.

Lung deposition of 99mTc-radiolabeled albuterol delivered through a pressurized metered dose inhaler and spacer with facemask or mouthpiece in children with asthma

BACKGROUND

Research on the use of a pressurized metered dose inhaler (pMDI) with spacer (pMDI/spacer) in children has indicated oral inhalation via the spacer mouthpiece is more efficient than the combination of oral and nasal inhalation that occurs when a pMDI/spacer is used with a facemask. Changes in pMDI formulations and developments in spacer and facemask designs have highlighted the need for new comparative studies of spacer use, particularly focusing on the age at which children can be taught to transition from use of a pMDI/spacer with facemask to use of the spacer mouthpiece.

METHODS

Twelve children aged 3-5 years (7 males) with stable asthma were recruited. Of these, 10 children (6 males) completed both arms of the study. A transmission scan of each compliant subject was taken using a 37 MBq (99m)Tc flood source. Actuations (2-3) of a (99m)Tc-radiolabeled albuterol pMDI were administered through an antistatic spacer (OptiChamber Diamond) via either a facemask (medium LiteTouch facemask), or the spacer mouthpiece. The subject's inhalation pattern was simultaneously recorded using a pMDI Datalogger, and narrative data relating to tolerance and compliance were documented. Anterior and posterior planar scintigraphic scans were taken immediately after aerosol administration.

RESULTS

Mean (SD) lung deposition (% total dose) was 18.1 (9.1)% with the facemask and 22.5 (7.9)% with the spacer mouthpiece (p>0.05). Peripheral lung deposition (expressed as peripheral:central (P:C) ratio) was higher in 7 out of 10 children with the facemask compared with the spacer mouthpiece: 1.3 (0.26) vs. 1.2 (0.35); (p=0.11). Head and neck deposition was higher with use of the facemask compared with the spacer mouthpiece: 19.7 (10.6)% vs. 10.8 (5.3)% (p=0.011).

CONCLUSIONS

Lung deposition achieved using the spacer with facemask was higher than previously reported, with a difference of only 4.4% of total dose measured compared to the deposition with mouthpiece. This may be due to a combination of factors including pMDI formulation, and use of an antistatic spacer with a flexible, well-fitting facemask.

The evolution of spacers and valved holding chambers

Spacers and valved holding chambers (VHCs) are pressurized metered dose inhaler (pMDI) accessory devices, designed to overcome problems that patients commonly experience when administering aerosol via a pMDI. Spacers were developed in direct response to patient-related issues with pMDI technique, particularly, poor coordination between actuation and inhalation, and local side-effects arising from oropharyngeal deposition. Current clinical guidelines indicate the need for widespread prescription and use of spacers, but, despite their apparent ubiquity, the devices themselves are, unfortunately, all too commonly "disused" by patients. An understanding of the background from which spacers developed, and the key factors influencing the optimization of the spacer and the later VHC, is crucial to developing an appreciation of the potential of these devices, both contemporary and future, for improving the delivery of pressurized aerosols to patients. This review, informed by a full patent search and an extensive scientific literature review, takes into account the clinical and laboratory evidence, commercial developments, and the sometimes serendipitous details of scientific anecdotes to form a comprehensive perspective on the evolution of spacers, from their origins, in the early days of the pMDI, up to the present day.

Efficient Nose-to-Lung (N2L) Aerosol Delivery with a Dry Powder Inhaler

PURPOSE

Delivering aerosols to the lungs through the nasal route has a number of advantages, but its use has been limited by high depositional loss in the extrathoracic airways. The objective of this study was to evaluate the nose-to-lung (N2L) delivery of excipient enhanced growth (EEG) formulation aerosols generated with a new inline dry powder inhaler (DPI). The device was also adapted to enable aerosol delivery to a patient simultaneously receiving respiratory support from high flow nasal cannula (HFNC) therapy.

METHODS

The inhaler delivered the antibiotic ciprofloxacin, which was formulated as submicrometer combination particles containing a hygroscopic excipient prepared by spray-drying. Nose-to-lung delivery was assessed using in vitro and computational fluid dynamics (CFD) methods in an airway model that continued through the upper tracheobronchial region.

RESULTS

The best performing device contained a 2.3 mm flow control orifice and a 3D rod array with a 3-4-3 rod pattern. Based on in vitro experiments, the emitted dose from the streamlined nasal cannula had a fine particle fraction <5 μm of 95.9% and mass median aerodynamic diameter of 1.4 μm, which was considered ideal for nose-to-lung EEG delivery. With the 2.3-343 device, condensational growth in the airways increased the aerosol size to 2.5-2.7 μm and extrathoracic deposition was <10%. CFD results closely matched the in vitro experiments and predicted that nasal deposition was <2%.

CONCLUSIONS

The developed DPI produced high efficiency aerosolization with significant size increase of the aerosol within the airways that can be used to enable nose-to-lung delivery and aerosol administration during HFNC therapy.

Aerosol therapy in children: challenges and solutions

Using aerosolized medications for the treatment of children has gained importance over the years. However, aerosol drug delivery to infants and pediatrics is not an easy task as it has been influenced by many challenges. Most aerosol devices have been designed for use in adults not for children. Therefore, they require some critical assessment in device selection and often a level of adaptation for use with smaller children. It is well documented that each aerosol device and interface that have been used for the treatment of children has its own advantages and challenges in drug delivery. This paper provides a comprehensive review of dosing, drug-device combination, aerosol devices and interfaces used for drug delivery to children with pulmonary diseases. Solutions to the challenges with the aim of optimizing aerosol therapy in this patient population are also discussed.

Demonstrating and assessing metered-dose inhaler-spacer technique: pediatric care providers' self-reported practices and perceived barriers

The National Asthma Education and Prevention Program recommends that providers demonstrate and assess metered-dose inhaler-spacer (MDI-S) technique at each medical visit. To examine practice behaviors and perceived barriers to demonstrating and assessing MDI-S technique, we surveyed pediatric providers (n = 114) at an inner-city academic medical center. While 82% of providers demonstrated MDI-S technique, only 5% of providers demonstrate the technique at every visit. Although 67% of providers assessed MDI-S technique, only 13% assess the technique at every visit. None of the providers used MDI-S checklist for assessment. Attendings were more likely than residents to demonstrate with illustrations (24% vs 6%, P = .01) and when patient's asthma was not well controlled (68% vs 47%, P = .05). Provider-identified barriers included limited access to MDI-S device, lack of time, and inadequate knowledge. Suggestions to address barriers include in-service training, device access, and nurse/health educators to alleviate the time constraints. Clinic modifications and education are needed.

Comparison of in vitro deposition of pharmaceutical aerosols in an idealized child throat with in vivo deposition in the upper respiratory tract of children

PURPOSE

Deposition of drug emitted from two commercially available inhalers was measured in an in vitro child oral airway model and compared to existing in vivo data to examine the ability of the child model to replicate in vivo deposition.

METHODS

In vitro deposition of drug from a QVAR® pressurized metered dose inhaler (pMDI) and Pulmicort® Turbuhaler® dry powder inhaler (DPI) in an Idealized Child Throat (1) and downstream filter was measured using UV spectroscopy and simulated realistic breathing profiles. Potential effects of ambient relative humidity ranging from 10% to 90% on deposition were also considered.

RESULTS

In vitro QVAR pMDI deposition in the idealized mouth-throat at 50% RH (39.2 ± 2.3% of delivered dose) compared well (p>0.05) with in vivo extrathoracic deposition in asthmatic children age 8 to 14 (45.8 ± 12.3%). In vitro Turbuhaler DPI deposition in the idealized mouth-throat at 50% RH (69.0 ± 1.5%) matched in vivo extrathoracic deposition (p>0.05) in 6 to 16 year old children with cystic fibrosis (70.4 ± 21.2%). The effects of ambient humidity were found to be insignificant for Turbuhaler and minor for QVAR.

CONCLUSIONS

The Idealized Child Throat successfully mimics in vivo deposition data in school age children for the inhalers tested, and may provide a standard platform for optimizing pediatric treatment with inhaled pharmaceutical aerosols.

Evaluation of MDI-spacer utilization and technique in caregivers of urban minority children with persistent asthma

OBJECTIVE

Incorrect Metered-Dose Inhaler (MDI)-spacer technique can result in decreased drug delivery to distal airways and poor asthma outcomes. There is lack of research to examine whether the caregivers utilize proper technique when applying an MDI-spacer delivery system for young minority children with persistent asthma in the United States. The objective of this study was to evaluate MDI-spacer utilization and technique among the caregivers of Bronx minority children with persistent asthma and to determine characteristics associated with correct use.

METHODS

We analyzed data from 169 caregivers of urban minority children with persistent asthma (aged 2-9 years). MDI-spacer device technique was assessed using a 10-step checklist derived from the national guidelines, literature and manufacturers' instructions. Based on the median MDI-technique score of six steps demonstrated accurately, caregivers were categorized as correct (seven or more) or incorrect (six or less) users.

RESULTS

Of the 169 caregivers, 95% were mothers, mean age 32.3 years (SD 7.6), 56% were unemployed; 74% of the children were Hispanic, 87% had either "not well controlled" or "very poorly controlled" asthma, 92% had a spacer at home and 71% used it "all" or "most" of the time. Only one caregiver correctly demonstrated all 10 steps of the MDI-spacer technique. Child's having one or more asthma-related hospitalizations in the past 12 months and higher caregiver educational level were independent predictors of correct MDI-spacer technique.

CONCLUSIONS AND RELEVANCE

The caregivers of urban, minority children with persistent asthma lack proper MDI-spacer technique, suggesting the potential value of both targeted short- and long-term educational interventions.

Comparison of the bronchodilating effects of albuterol delivered by valved vs. non-valved spacers in pediatric asthma

INTRODUCTION

Inhaled therapy using a metered-dose inhaler (MDI) with attached valved holding chamber has been increasingly recognized as the optimal method for delivering bronchodilators for asthma treatment. However, mainly due to the high cost of these valved holding chambers in many developing countries, the use of non-valved spacers is frequent, despite the scarce evidence that supports their efficacy. The aim of this study was to compare the bronchodilator response to albuterol administered by MDI with and without a valved spacer.

METHODS

In a randomized, two-period, two-sequence crossover clinical trial, we analyzed 31 stable asthmatic children (6-18 yrs of age) on two consecutive days, who were randomly assigned to receive 100 μg of albuterol MDI through either a locally produced valved spacer or a non-valved spacer. The next day, a crossover treatment was employed through the use of the other spacer. Spirometry was recorded before and after each albuterol administration.

RESULTS

As we were not able to identify any sequence or carryover effect, we tested for treatment effects in both periods. No significant differences in the absolute change in FEV(1) (0.20 ± 0.17 vs. 0.18 ± 0.16, p = 0.63), FVC (0.07 ± 0.13 vs. 0.07 ± 0.16, p = 0.88), or MMEF (0.49 ± 0.31 vs. 0.43 ± 0.39, p = 0.53) after bronchodilator administration were found between the use of valved and non-valved spacers.

CONCLUSIONS

In stable asthmatic children, albuterol administered through MDI using a non-valved spacer produces a bronchodilator response similar to that of a spacer with a valve that requires an inhalatory opening pressure (with flows between 2 and 32 l/min) that even toddlers with bronchial obstruction can easily generate.

Medication use in children with asthma: not a child size problem

OBJECTIVE

The global burden of pediatric asthma is high. Governments and health-care systems are affected by the increasing costs of childhood asthma--in terms of direct health-care costs and indirect costs due to loss of parental productivity, missed school days, and hospitalizations. Despite the availability of effective treatment, the current use of medications in children with asthma is suboptimal. The purpose of this review is to scope the empirical literature to identify the problems associated with the use of pediatric asthma medications. The findings will help to design interventions aiming to improve the use of asthma medications among children.

METHODS

A literature search using electronic search engines (i.e., Medline, International Pharmaceutical Abstracts (IPA), PubMed, PsycINFO, and Cumulative Index to Nursing and Allied Health Literature (CINAHL)) and the search terms "asthma," "children," and "medicines" (and derivatives of these keywords) was conducted.

RESULTS

The search terms were expanded to include emergent themes arising out of search findings. Content themes relating to parents, children themselves, health-care professionals, organizational systems, and specific medications and devices were found. Within these themes, key issues included a lack of parental knowledge about asthma and asthma medications, lack of information provided to parents, parental beliefs and fears, parental behavioral problems, the high costs of medications and devices, the child's self-image, the need for more child responsibility, physician nonadherence to prescribing guidelines, "off-label" prescribing, poor understanding of teachers, lack of access to educational resources, and specific medications.

CONCLUSION

These key issues should be taken into account when modifying the development of educational tools. These tools should focus on targeting the children themselves, the parent/carers, the health-care professionals, and various organizational systems.

Albuterol enantiomer levels, lung function and QTc interval in patients with acute severe asthma and COPD in the emergency department

Background

This observational study was designed to investigate plasma levels of albuterol enantiomers among patients with acute severe asthma or COPD presenting to the emergency department, and the relationship with extra-pulmonary cardiac effects (QTc interval) and lung function. Recent reviews have raised concerns about the safety of using large doses of β₂-agonists, especially in patients with underlying cardiovascular comorbidity. It has been demonstrated that significant extrapulmonary effects can be observed in subjects given nebulised (R/S)-albuterol at a dose of as little as 6.5 mg.

Methods

Blood samples were collected and plasma/serum levels of (R)- and (S)-albuterol enantiomers were determined by LC-MS and LC-MS/MS assay. Extra-pulmonary effects measured at presentation included ECG measurements, serum potassium level and blood sugar level, which were collected from the hospital medical records.

Results

High plasma levels of both enantiomers were observed in some individuals, with median (range) concentrations of 8.2 (0.6-24.8) and 20.6 (0.5-57.3) ng/mL for (R)- and (S)- albuterol respectively among acute asthma subjects, and 2.1 (0.0-16.7) to 4.1 (0.0-36.1) ng/mL for (R)- and (S)- albuterol respectively among COPD subjects. Levels were not associated with an improvement in lung function or adverse cardiac effects (prolonged QTc interval).

Conclusions

High plasma concentrations of albuterol were observed in both asthma and COPD patients presenting to the emergency department. Extra-pulmonary cardiac adverse effects (prolonged QTC interval) were not associated with the plasma level of (R)- or (S)-albuterol when administered by inhaler in the emergency department setting. Long-term effect(s) of continuous high circulating albuterol enantiomer concentrations remain unknown, and further investigations are required.

Characteristics of spacer device use by patients with asthma and COPD

OBJECTIVE

Spacer devices (SD) in conjunction with metered dose inhalers (MDI) have been shown to be as effective as saline nebulizers for the delivery of beta-agonists. A preliminary study suggests that SDs are not consistently used. The purpose of this study was to investigate patterns of SD ownership and use to identify potential targets for future educational efforts to increase ownership and use of SD.

METHODS

Cross-sectional convenience sample survey of patients presenting to an academic Emergency Department (ED) with a history of asthma/COPD (chronic obstructive pulmonary disease). Informed consent was obtained. Survey data included demographics, association with a primary care physician (PCP), SD ownership, patterns of use, opinions of efficacy about SD and disease severity assessed by duration of asthma/COPD, prior ED visits, hospitalizations, and history of prior intubation. Patterns of use are described and univariate and multivariate analyses were used to identify factors associated with SD ownership.

RESULTS

Of the 313 patients, 55.9% were female, the mean age was 46.0 years (standard deviation 14.7), 54.3% were white, and 143 patients (45.7%) reported owning a SD. A total of 36.4% reported a prior hospitalization for their condition and 24% reported a history of being intubated. Less than half of patients presenting with asthma or COPD exacerbation that reported owning a SD used it the day of presentation to the ED. Logistic regression identified having a PCP and a history of prior hospitalization for asthma/COPD as factors independently associated with SD ownership (odds ratio [OR] 1.7, 95% confidence interval [CI] 1.1-2.7 and OR 2.2, CI 1.3-3.5, respectively).

CONCLUSION

A majority of patients with asthma/COPD do not own a SD. These data suggest that there is significant opportunity for educational efforts directed at a broad range of asthma/COPD patients in hopes of increasing ownership and use of SD.

Assessment of inhalation technique in children in general practice: increased risk of incorrect performance with new device

In a general practice based population 76% of 530 children inhaling asthma medication inhaled correctly. However, important differences among inhalers were found. Children with a pressurized metered-dose inhaler without a spacer device performed worst, with only 22% inhaling without essential errors. At a second evaluation of the inhaler technique, one year after the first assessment, performances with a new device were more often incorrect versus the unchanged devices (21.1% and 10.8%, respectively; p = 0.01). Providing children with a new device should be carefully controlled over time especially because these children are error prone.