Wet Nebulisation Research Articles

Characterization of Aerosols of Titanium Dioxide Nanoparticles Following Three Generation Methods Using an Optimized Aerosolization System Designed for Experimental Inhalation Studies.

Nanoparticles (NPs) can be released in the air in work settings, but various factors influence the exposure of workers. Controlled inhalation experiments can thus be conducted in an attempt to reproduce real-life exposure conditions and assess inhalation toxicology. Methods exist to generate aerosols, but it remains difficult to obtain nano-sized and stable aerosols suitable for inhalation experiments. The goal of this work was to characterize aerosols of titanium dioxide (TiO2) NPs, generated using a novel inhalation system equipped with three types of generators—a wet collision jet nebulizer, a dry dust jet and an electrospray aerosolizer—with the aim of producing stable aerosols with a nano-diameter average (<100 nm) and monodispersed distribution for future rodent exposures and toxicological studies. Results showed the ability of the three generation systems to provide good and stable dispersions of NPs, applicable for acute (continuous up to 8 h) and repeated (21-day) exposures. In all cases, the generated aerosols were composed mainly of small aggregates/agglomerates (average diameter <100 nm) with the electrospray producing the finest (average diameter of 70–75 mm) and least concentrated aerosols (between 0.150 and 2.5 mg/m3). The dust jet was able to produce concentrations varying from 1.5 to 150 mg/m3, and hence, the most highly concentrated aerosols. The nebulizer collision jet aerosolizer was the most versatile generator, producing both low (0.5 mg/m3) and relatively high concentrations (30 mg/m3). The three optimized generators appeared suited for possible toxicological studies of inhaled NPs.

Inhaled antibiotics: dry or wet?

Dry powder inhalers (DPIs) delivering antibiotics for the suppressive treatment of Pseudomonas aeruginosa in cystic fibrosis patients were developed recently and are now increasingly replacing time-consuming nebuliser therapy. Noninferiority studies have shown that the efficacy of inhaled tobramycin delivered by DPI was similar to that of wet nebulisation. However, there are many differences between inhaled antibiotic therapy delivered by DPI and by nebuliser. The question is whether and to what extent inhalation technique and other patient-related factors affect the efficacy of antibiotics delivered by DPI compared with nebulisers. Health professionals should be aware of the differences between dry and wet aerosols, and of patient-related factors that can influence efficacy, in order to personalise treatment, to give appropriate instructions to patients and to better understand the response to the treatment after switching. In this review, key issues of aerosol therapy are discussed in relation to inhaled antibiotic therapy with the aim of optimising the use of both nebulised and DPI antibiotics by patients. An example of these issues is the relationship between airway generation, structural lung changes and local concentrations of the inhaled antibiotics. The pros and cons of dry and wet modes of delivery for inhaled antibiotics are discussed.

Holding chambers (spacers) versus nebulisers for beta-agonist treatment of acute asthma.

In acute asthma inhaled beta(2)-agonists are often administered by nebuliser to relieve bronchospasm, but some have argued that metered-dose inhalers with a holding chamber (spacer) can be equally effective. Nebulisers require a power source and need regular maintenance, and are more expensive in the community setting. To assess the effects of holding chambers (spacers) compared to nebulisers for the delivery of beta(2)-agonists for acute asthma. We searched the Cochrane Airways Group Trial Register and reference lists of articles. We contacted the authors of studies to identify additional trials. Date of last search: February 2013. Randomised trials in adults and children (from two years of age) with asthma, where spacer beta(2)-agonist delivery was compared with wet nebulisation. Two review authors independently applied study inclusion criteria (one review author for the first version of the review), extracted the data and assessed risks of bias. Missing data were obtained from the authors or estimated. Results are reported with 95% confidence intervals (CIs). This review includes a total of 1897 children and 729 adults in 39 trials. Thirty-three trials were conducted in the emergency room and equivalent community settings, and six trials were on inpatients with acute asthma (207 children and 28 adults). The method of delivery of beta(2)-agonist did not show a significant difference in hospital admission rates. In adults, the risk ratio (RR) of admission for spacer versus nebuliser was 0.94 (95% CI 0.61 to 1.43). The risk ratio for children was 0.71 (95% CI 0.47 to 1.08, moderate quality evidence). In children, length of stay in the emergency department was significantly shorter when the spacer was used. The mean duration in the emergency department for children given nebulised treatment was 103 minutes, and for children given treatment via spacers 33 minutes less (95% CI -43 to -24 minutes, moderate quality evidence). Length of stay in the emergency department for adults was similar for the two delivery methods. Peak flow and forced expiratory volume were also similar for the two delivery methods. Pulse rate was lower for spacer in children, mean difference -5% baseline (95% CI -8% to -2%, moderate quality evidence), as was the risk of developing tremor (RR 0.64; 95% CI 0.44 to 0.95, moderate quality evidence). Nebuliser delivery produced outcomes that were not significantly better than metered-dose inhalers delivered by spacer in adults or children, in trials where treatments were repeated and titrated to the response of the participant. Spacers may have some advantages compared to nebulisers for children with acute asthma.

Cost-effectiveness of Metered-Dose Inhalers for Asthma Exacerbations in the Pediatric Emergency Department

Q Doan, A Shefrin, D Johnson. Pediatrics. 2011;127(5). Available at: www.pediatrics.org/cgi/content/full/127/5/e1105 To compare the incremental cost and effects (eg, averted admission to hospital) of using a metered-dose inhaler (MDI) against wet nebulization to deliver bronchodilators for the treatment of mildly to moderately severe asthma in pediatric emergency departments (EDs). The population was obtained from a Cochrane systematic review in which the efficacy of using MDIs …

Metered-dose Inhalers in the Emergency Department

Source: Doan Q, Shefrin A, Johnson D. Cost-effectiveness of metereddose inhalers for asthma exacerbations in the pediatric emergency department. Pediatrics. 2011; 127(5): e1105– e1111; doi: 10.1542/peds.2010-2963To compare the cost-effectiveness of two modes of beta-agonist delivery in the treatment of children with an acute exacerbation of asthma, investigators obtained asthma-related costs from two tertiary Canadian children’s hospitals (British Columbia and Alberta). In development of a decision model, cost data were combined with asthma outcomes as published in a Cochrane systematic review (SR)1 that compared metered-dose inhaler (MDI) with wet nebulization. Outcome data from children who were aged 2 to 18 years with a mild to moderate acute exacerbation of asthma in the emergency department (ED) who did not require intensive care unit treatment were extracted from the SR. Costs were analyzed from a hospital perspective based on health care utilization within two days of an ED visit, with ED discharge considered a success, and hospital admission considered a failure.A range of costs were projected based on two treatment protocols. Both protocols included three to six treatments of albuterol with MDI and spacer (500–1,000 mcg) versus three to six treatments of nebulized albuterol (2.5–5.0 mg), all given at 20-minute intervals. In the second protocol, three treatments of ipratropium at 20-minute intervals via MDI or nebulization were assumed in the cost calculations. Cost values were established in Canadian dollars for nursing hours, pharmacologic costs (one MDI per patient), daily hospital stay (including physician fees, nursing, and pharmacologic costs), and device costs (eg, spacers or nebulizer tubing) using hospital data. Mode of delivery of albuterol was assumed to be associated with neither a differential labor cost in the ED nor hospital admission length of stay. The incremental cost-effectiveness ratio (ICER) was calculated per hospital admission averted, representing the difference in costs associated with delivery mode divided by the difference in probability of admission for a child treated with either mode. Sensitivity analyses were performed and Monte Carlo simulations were calculated around the baseline ICER to account for variability of model variables and costs.Although the point estimate favored the MDI mode of delivery, there was no statistically significant difference in the probability of admission between delivery modes. However, a net cost savings of nearly $155 (Canadian) per patient was observed with the MDI protocol. The MDI protocol also resulted in a greater likelihood of preventing hospital admissions with reduced cost, resulting in about a −$2,500 (Canadian) ICER per averted admission. In Monte Carlo simulations and sensitivity analysis, the ICER favored the MDI protocol in 90% to 98% of points or runs, respectively, even with inclusion of ipratropium in the protocols.The authors conclude that delivery of albuterol using MDIs with spacers to children with mild to moderate exacerbations would result in both a reduced risk of hospitalization and cost savings in most cases. The authors are careful to state that the cost savings are driven in large part by the lower risk of hospitalization with the use of the MDI protocols, despite the lower costs for nebulized drugs and associated devices.Dr Stevenson has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.An estimated 10 million children in the United States have asthma,2 and many will unfortunately experience an exacerbation resulting in an ED visit. Systemic corticosteroids and beta-agonists remain the mainstay of therapy. A significant body of literature supports MDIs as a delivery mode that is both faster than and at least as efficacious as wet nebulization, particularly for mild to moderate exacerbations, as summarized in the SR.1 Cost of the inhalers and spacers, especially associated with ipratropium delivery (which is indicated for moderate to severe exacerbations),3 has been a significant barrier to adoption of the MDI as the preferred delivery device in many pediatric EDs.4This carefully modeled study addresses the critical cost issue and shows that even under the worst case scenarios (very high costs of albuterol and ipratropium MDIs) the MDI delivery mode is a superior strategy, resulting in both a reduced risk of hospitalization and cost savings for hospitals and potentially, as the authors note, families and the health care system. Although cost variability in the United States may be greater due to the mix of payers, the sensitivity analyses suggest that the MDI strategy would be favored in most markets.

Cost-effectiveness of Metered-Dose Inhalers for Asthma Exacerbations in the Pediatric Emergency Department

To compare the incremental cost and effects (averted admission) of using a metered-dose inhaler (MDI) against wet nebulization to deliver bronchodilators for the treatment of mild to moderately severe asthma in pediatric emergency departments (EDs). We measured the incremental cost-effectiveness from the perspective of the hospital, by creating a model using outcome characteristics from a Cochrane systematic review comparing the efficacy of using MDIs versus nebulizers for the delivery of albuterol to children presenting to the ED with asthma. Cost data were obtained from hospitals and regional authorities. We determined the incremental cost-effectiveness ratio and performed probabilistic sensitivity analyses using Monte Carlo simulations. Using MDIs in the ED instead of wet nebulization may result in net savings of Can$154.95 per patient. Our model revealed that using MDIs in the ED is a dominant strategy, one that is more effective and less costly than wet nebulization. Probabilistic sensitivity analyses revealed that 98% of the 10 000 iterations resulted in a negative incremental cost-effectiveness ratio. Sensitivity analyses around the costs revealed that MDI would remain a dominant strategy (90% of 10 000 iterations) even if the net cost of delivering bronchodilators by MDI was Can$70 more expensive than that of nebulized bronchodilators. Use of MDIs with spacers in place of wet nebulizers to deliver albuterol to treat children with mild-to-moderate asthma exacerbations in the ED could yield significant cost savings for hospitals and, by extension, to both the health care system and families of children with asthma.

Effects of restrictions on reimbursement for pharmaceutical drugs

Our review on restrictions to reimbursement by drug benefit plans (1) is part of an emerging series on pharmaceutical policies from the Cochrane Effective Practice and Organization of Care group (2–5). As expected, we found strong evidence that these restrictions do lead to lower spending on drugs but the more important question for us to answer was whether the savings associated with the restrictions can be obtained without unintended health consequences or shifting costs to other parts of the health care system. The answer is yes, but not always. The Cochrane Collaboration has taken up the challenge of Archie Cochrane’s vision of systematically reviewing the best available evidence in all areas of health care, to support clinical practice. We have a similar vision for a collection of reviews to support informed decision making on pharmaceutical policies. Many people are not aware of how much the science of pharmaceutical policy has advanced, with the availability of large administrative datasets and the ability of researchers to process anonymous data from millions of routine transactions. Our review is the fourth to be completed in the planned series of 13 Cochrane reviews of pharmaceutical policy. The other three completed reviews looked at reference pricing, copayments and caps, and physician incentives; and have all yielded insights that can be used to formulate better pharmaceutical policies. As we brought together the data for our review, we were surprised to find how much the results varied by drug class. In the 29 included studies, nine drug classes had been targeted for restriction. Most looked at policies restricting gastric acid suppressants and non steroidal anti inflammatory drugs, or NSAIDS. For these, there is good evidence that restrictive policies lead to savings without increasing the use of other health services. We also found evidence supporting restrictions for wet nebulizer respiratory drugs and fluroquinolone antimicrobials. However, second generation antipsychotic medications provided an exception to the generally positive findings. There was good evidence that restrictions for these were associated with treatment discontinuity and increased outpatient visits. This makes them poor targets for restrictive policies. We also found that the available evidence does not support restrictions for anti-platelets and angiotensin receptor blocker medications. The global nature of our review made us aware of European strategies to encourage the use of cost effective medications to prevent secondary complications of high blood pressure and blood cholesterol. We found a small but high quality body of evidence supporting the lifting or exemption of restrictions, when these drugs are used for secondary prevention. The evidence available for our review applies mostly to older or low income populations, because the research was conducted using data from publicly funded drug benefit plans. However, the policies are also used by employer or private insurance plans and our findings might be relevant in those settings. Spending on prescription medications has increased dramatically in recent years, while public funding has contracted, so the use of policies to control costs may be essential to ensure that drug benefit plans can be sustained. We are excited about our early steps in realizing the vision of providing policy makers with systematic reviews of pharmaceutical policy across all 13 major areas. These policies can have enormous ramifications for the health of populations and the sustainability of health systems. We will be moving on to investigate policies that determine which drugs are reimbursed but the body of research in this area is growing so quickly that we also need to develop strategies to ensure the regular updating of the existing reviews.

MULTIFACETED INTERVENTION FOR REDUCING INADEQUATE PRESCRIPTION OF INTRAHOSPITAL NEBULIZERS

PURPOSE: At a time of diminishing healthcare resources, clinical guidelines are considered essential tools to reduce inappropriate use of drugs. An audit conducted at our university hospital demonstrated the need to reduce unjustified prescriptions of wet nebulizer (WN) therapy, in order to comply with guidelines and cut costs. The objectives of this study are to establish the major motivating factors for prescription and to evaluate the impact of an intervention aimed at improving doctors' behaviors.

Reconciliation of Cascade Impaction during Wet Nebulization

Cascade impaction is an important tool for measuring aerosol distributions from wet nebulizers; however, results vary depending on laboratory and technique. The focus of this study was to reconcile the contribution of particle evaporation to these reported differences. To measure the effect of evaporation, we compared aerosol distributions from circuits ventilated with humidified air, ambient air, and a nonventilated, standing cloud circuit using low-flow cascade impaction (1.0 L/min). Aerosol distributions were similar for the humidified/ventilated and standing cloud models [mass median aerodynamic diameter (MMAD) 3.4 microm, and 3.6 microm Aero-Eclipse, 5.8 and 5.1 microm Misty-Neb, 3.8 and 3.2 microm Pari LC Plus]. In the ventilated/ambient air model, smaller particle sizes were measured (2.2 microm AeroEclipse, 2.4 microm Misty-Neb, 2.1 microm Pari LC Plus). Techniques of cascade impaction significantly affected measured aerosol distributions. MMAD were defined by nebulizer type and conditions of particle evaporation not by impactor. Aerosol mixing with ambient air caused evaporation and shrinkage of particles, and accounts for differences between laboratories. Patients breathing from nebulizers may entrain ambient air possibly affecting deposition.

Use of wet nebulized inhaled respiratory medications under criteria-based reimbursement guidelines in a publicly funded seniors' pharmacare program in Nova Scotia, Canada

During the 1999/2000 fiscal year, approximately 19% of beneficiaries in the Nova Scotia Seniors' Pharmacare Program (NSSPP), a publicly funded drug insurance program in Nova Scotia, Canada, received inhaled respiratory medications by wet nebulization. The cost was estimated at more than Can $2 million annually. On August 1, 2000, the NSSPP initiated new criteria-based reimbursement guidelines for wet nebulized respiratory medications, requiring prior authorization. Within the NSSPP, we examined approved reimbursement requests to determine demographic characteristics of those who accessed wet nebulized therapy through exception criteria, compare these factors between those who accessed wet nebulized therapy within the exception criteria and those who fell outside the criteria, identify indications for use of wet nebulization, and determine patterns of wet nebulization use. Two hundred approved requests, received between August 1, 2000, and April 30, 2001, were randomly selected and reviewed for indications and patterns of use. Of 200 requests reviewed, 28 were excluded due to coverage in another Pharmacare program (Community Services). Of the 172 requests reviewed, 27% were for nursing home or other residential care facility residents. Indications and patterns of use differed only by place of residence (P<0.001). The majority of indications (72%) fell within outlined reimbursement criteria, with the most frequently cited indication (56%) being inability to use portable inhalers due to cognitive or physical disability. Almost one third (28%) of exception requests were approved for other reasons (31% of these were for short-term use [ie, <3 months] secondary to an acute respiratory infection or for palliative care; 69% continued to access wet nebulization because of a preference or a perception of greater effectiveness). Examination of patterns of use demonstrated that 36% of beneficiaries, primarily community dwelling (P < 0.001), were using wet nebulized therapy and portable inhalers concurrently. The majority of approved requests for wet nebulization criteria fell within the established reimbursement guidelines. Many approvals outside of guidelines were clinically valid. Approval of requests outside the criteria highlights the need for flexibility in the claims administrative and adjudication system to respond to unique circumstances not covered by established criteria. However, concurrent use of wet nebulization and portable inhalers by some beneficiaries suggests suboptimal use of portable inhalers, the need for portable inhalers for patients using wet nebulization when they leave their residence, and the need for more patient education.

Dry powder inhalation versus wet nebulisation delivery of antibiotics in cystic fibrosis patients

Inhalation of antipseudomonal antibiotics is a cornerstone in treating cystic fibrosis patients. It has shown to be effective in slowing down the process of pulmonary deterioration and decreasing the incidence of infectious exacerbations. The focus is now on innovating drug delivery devices, sometimes combined with specific drug formulations, which allow for the administration of large doses in a short time frame and in a reproducible way. Adaptive aerosol delivery devices are promising, but do not have a distinct position as yet because of the lack of long-term data. The position of dry powder inhalation of antibiotics in cystic fibrosis treatment is still confined to pilot studies. Until more clinical data are available, the suboptimal, conventional jet nebulisers are the mainstay in antipseudomonal inhalation therapy in cystic fibrosis.

Cochrane review: Holding chambers (spacers) versus nebulisers for beta‐agonist treatment of acute asthma

AbstractBackgroundIn acute asthma inhaled β2‐agonists are often administered to relieve bronchospasm by wet nebulisation, but some have argued that metered‐dose inhalers with a holding chamber (spacer) can be equally effective. Nebulisers require a power source and need regular maintenance, and are more expensive in the community setting.ObjectivesTo assess the effects of holding chambers (spacers) compared to nebulisers for the delivery of ß2‐agonists for acute asthma.Search strategyWe last searched the Cochrane Airways Group trials register in January 2006 and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2005).Selection criteriaRandomised trials in adults and children (from two years of age) with asthma, where spacer ß2‐agonist delivery was compared with wet nebulisation.Data collection and analysisTwo reviewers independently applied study inclusion criteria (one reviewer for the first version of the review), extracted the data and assessed trial quality. Missing data were obtained from the authors or estimated. Results are reported with 95% confidence intervals (CI).Main resultsThis review has been updated in January 2006 and four new trials have been added. 2066 children and 614 adults are now included in 25 trials from emergency room and community settings. In addition, six trials on in‐patients with acute asthma (213 children and 28 adults) have been reviewed. Method of delivery of ß2‐agonist did not appear to affect hospital admission rates. In adults, the relative risk of admission for spacer versus nebuliser was 0.97 (95% CI 0.63 to 1.49). The relative risk for children was 0.65 (95% CI: 0.4 to 1.06). In children, length of stay in the emergency department was significantly shorter when the spacer was used, with a mean difference of ‐0.47 hours (95% CI: ‐0.58 to ‐0.37). Length of stay in the emergency department for adults was similar for the two delivery methods. Peak flow and forced expiratory volume were also similar for the two delivery methods. Pulse rate was lower for spacer in children, mean difference ‐7.6% baseline (95% CI: ‐9.9 to ‐5.3% baseline).Authors' conclusionsMetered‐dose inhalers with spacer produced outcomes that were at least equivalent to nebuliser delivery. Spacers may have some advantages compared to nebulisers for children with acute asthma.Plain language summarySpacers (holding chambers) can be as effective as nebulisers for delivering β2‐agonist drugs to relieve acute asthma.In acute asthma attacks higher doses of inhaled β2‐agonists (reliever inhalers) are used to overcome the narrowing of the passages in the lungs. The medication can be given by wet nebulisation or from an inhaler with a spacer device (holding chamber). This review now includes in‐patient studies, as well as those in casualty and community setting, comparing these two delivery methods in acute asthma attacks. In adults, no important differences were found between the two methods, whilst in children those randomised to wet nebulisation spent longer in casualty. Metered‐dose inhalers with a spacer can perform at least as well as wet nebulisation in delivering β2‐agonists in acute asthma.

Design and in vitro performance testing of multiple air classifier technology in a new disposable inhaler concept (Twincer ®) for high powder doses

Dry powder inhalation of antibiotics in cystic fibrosis (CF) therapy may be a valuable alternative for wet nebulisation, because it saves time and it improves lung deposition. In this study, it is shown that the use of multiple air classifier technology enables effective dispersion of large amounts of micronised powder (up to 25 mg). X 50-values of the aerosol from laser diffraction analysis obtained with the Twincer ® disposable inhaler concept (containing multiple air classifier technology) are practically the same as that for the pure drug in the range of dose weights between 0 and 25 mg. Only for the highest dose weights, a minor fraction (5–7.5%) of small agglomerates (5–15 μm) is released from the inhaler. Moreover, the size distribution of the aerosol is practically the same at 1 and 4 kPa. Cascade impactor results confirm the good performance of the multiple classifier concept. Unprocessed micronised particles or soft spherical agglomerates can be used, and special particle engineering processes are not necessary. Only a minor fraction of coarse sweeper crystals in the formulation is desired to reduce the total inhaler losses for colistin sulfomethate to less than 5–6% at 4 kPa. The classifiers can be designed to retain these crystals with more than 95% efficiency.

Impact of a Criteria‐Based Reimbursement Policy on the Use of Respiratory Drugs Delivered by Nebulizer and Health Care Services Utilization in Nova Scotia, Canada

In February 2000, the Nova Scotia Seniors' Pharmacare Program announced a change in the reimbursement of respiratory drugs that added specific reimbursement criteria for wet nebulization therapy. Policy implementation coincided with multifaceted interventions to assist patients and providers with the change. To assess the impact of the new policy and associated interventions on the use of wet nebulization and portable inhaler delivery systems of respiratory drugs and on the utilization of health services. The administrative claims database identified all beneficiaries (age > or = 65 yrs) who received at least one respiratory drug prescription in the 12 months before the study. These patients were then grouped into the wet nebulization cohort or the control cohort receiving a metered-dose or a dry-powder inhaler. The study period was from April 1998-February 2002. Use of respiratory drugs, physician visits, and hospitalizations were compared between study cohorts using an interrupted time-series design. A sharp decrease was noted in use of wet nebulization after the policy announcement, along with an increase in use of short-acting beta2-agonists and anticholinergic agents delivered by metered-dose or drypowder inhaler. From December 1999 to December 2001, in the heavy wet nebulization cohort (a subset of the wet nebulization cohort), wet nebulization use dropped from 100% to 35%; in the wet nebulization cohort, wet nebulization use decreased from 67% to 20%. Rates of spacer device use were 42%, 31%, and 17% in the heavy wet nebulization, wet nebulization, and control cohorts, respectively, in December 2001. Rates of general practitioner visits and hospitalizations for respiratory conditions did not increase in the intervention cohorts after the policy announcement. In fact, relative to the control cohort, health services use in response to the policy and interventions in the wet nebulization cohort decreased. The reimbursement policy resulted in decreased use of respiratory drugs delivered by wet nebulization without a negative impact on general practitioner visits and hospitalizations for respiratory conditions.

Qualitative Perspectives on a Facilitated Change in Provincial Pharmacare Coverage

Background: During 2000, Nova Scotia's Department of Health implemented policy changes and educational interventions to encourage a switch from wet nebulization therapy to dry-dose delivery systems. The policy changes applied to beneficiaries of the Nova Scotia Pharmacare Programs, while the educational interventions had a broader provincial perspective. Methods: Researchers from Dalhousie University's Department of Family Medicine subsequently interviewed family physicians, pharmacists, and other health professionals to gather their views on the initiative. A single researcher (PLT) conducted interviews in the summer of 2001 in two settings. Interviews were audiotaped and transcribed. Analysis was guided by a grounded theory approach and facilitated by the use of QSR N5, a software program designed for computer-assisted qualitative data analysis. Results: The results are discussed in several categories, including the role of evidence, change strategies, user devotion to older delivery systems, and health care provider perspectives on policy change. Conclusion: Health care professionals interviewed agreed that this was a well-designed initiative in many respects. Participants identified several key elements that offer insights for future policy-implementation design, execution, and evaluation.

Evaluation Of The Bronchodilator Effect And Side Effect Profile Of A Salbutamol Dry Powder Inhaler Device: A Prospective Observational Study

Dry Powder Inhalation devices are currently used for the administration of inhaled Corticosteroids (ICS) and short acting B2 agonists (SABA). Most generic asthma medications are only available as Metered Dose Inhalers (MDI), with the consequence that Dry Powder Inhaler (DPI) devices are infrequently a therapeutic option in regions where medication costs are the overriding concern. Potential advantages of the DPI inhalation device as compared to MDI and nebulisation include; affordability, ease of use, reduced administration time and lack of CFC propellants. INTRODUCTION The aims of the study were to assess the bronchodilator efficacy and side effect profile of a low cost salbutamol DPI device when used in a busy Allergy Clinic. In addition, we sought to assess the attitudes of nursing staff, parents and patients, after having used the DPI device. METHODS For inclusion into the study, patients must have been able to activate the DPI through generating sufficient inspiratory flow. All consenting patients with clinical signs of asthma or if the FEV1 was 0.05. No patients required wet nebulisation. Adverse events reported were tremor in 4% and nausea in 8% of patients. Ninety eight percent of patients perceived the device easy to use and 94% of patients preferred the DPI to the MDI-Spacer combination. Ninety five percent of caregivers expressed confidence in the DPI device, were it to be required for the relief of acute asthma.

Lung deposition and respirable mass during wet nebulization.

For metered dose inhalers (MDIs), high-flow cascade impaction with a United States Pharmacopia (USP) throat provides a useful prediction of in vivo lung and oropharyngeal aerosol deposition. Particles expected to deposit in the lung are included in the "fine particle fraction" measured on the bench. Comparable in vitro standards are not available for nebulizers. The present study compared aerosol deposition in an in vitro model using low-flow cascade impaction with deposition in vivo in human subjects. A low-flow (1 Lmin), 10-stage cascade impactor measured aerodynamic distributions of aerosolized interferon-gamma (IFN-gamma) from two nebulizers (Misty-Neb and AeroEclipse). (99m)Technetium diethylene triaminepenta-acetic acid ((99m)Tc-DTPA) was used as the radiolabel. Two bench conditions were specified: no breathing (standing cloud) and simulated ventilation with a piston pump (tidal volume 750 mL frequency 25 per minute and duty cycle 0.5). Mass median aerodynamic diameter (MMAD) for both nebulizers was affected by ventilation (Misty-Neb vs. AeroEclipse: 5.2 vs. 4.6 microm for standing cloud and 3.1 vs. 2.2 microm during ventilation). In three subjects, measured values of oropharyngeal deposition averaged 68.1 +/- 0.08% for Misty-Neb and 30.9 +/- 0.03% for AeroEclipse. In vivo deposition patterns compared to aerosol distributions from both nebulizers indicated that, for wet nebulization, penetration of aerosol beyond the upper airways (fine particle fraction) will occur only for aerosol particles below 2.5 microm. This assessment requires that the bench aerosol distribution be measured under conditions of clinical use (i.e., during tidal breathing).

Teaching time for metered-dose inhalers in the emergency setting

Numata Y, Bourbeau J, Ernst P, et al (McGill University, Montreal, Quebec, Canada; Kanazawa University, Kanazawa City, Japan) Practitioners in some acute care settings are reluctant to use bronchodilator treatment with metered-dose inhalers (MDIs) as standard management, because such therapy requires clinicians to ensure optimal device use. The time required to teach patients correct inhaler use for the emergency treatment of asthma and chronic obstructive pulmonary disease was investigated prospectively. The patients were participants in a single-center, randomized clinical study comparing bronchodilator administration by MDI with a delivery enhancement device (MDI/DED) versus delivery by wet nebulizer. Sixty-one patients with asthma and 32 with chronic obstructive pulmonary disease were assigned to the MDI/DED arm and received instruction. Patients with asthma had a mean forced expiratory volume in 1 second (percent predicted) of 63.5%, and patients with chronic obstructive pulmonary disease, 39.5%. Five patients were unable to complete MDI teaching and thus subsequently received wet nebulization. For the remaining 88 patients, the median teaching time was 6.5 minutes. Independent factors associated with shorter teaching times were a higher initial arterial oxygen saturation, home DED use after previous MDI instruction, and a single initial bronchodilator treatment by wet nebulization. Most patients reported satisfaction with their MDI/DED teaching and treatment. In the emergency setting, MDI/DED teaching followed by self-medication can be accomplished successfully with a simple protocol. Subsequent MDI teaching may be facilitated by a single bronchodilator dose given by wet nebulization.

Holding chambers versus nebulisers for beta-agonist treatment of acute asthma.

In acute asthma inhaled beta-agonists are often administered to relieve bronchospasm by wet nebulisation, but some have argued that metered-dose inhalers with a holding chamber (spacer) can be equally effective. In the community setting nebulisers are more expensive, require a power source and need regular maintenance. There is controversy as to whether wet nebulisers are better than metered dose inhalers with holding chambers to deliver beta2-agonist medications for acute asthma. Comparisons of hospital and home use are also of interest. The objective of this review was to assess the effects of holding chambers compared to nebulisers for the delivery of beta2-agonists for acute asthma. We searched the Cochrane Airways Group trials register and the Cochrane Controlled Trials Register. Randomised trials in adults and children (from two years of age) with asthma, where holding chamber beta2-agonist delivery was compared with wet nebulisation. One reviewer applied study inclusion criteria and extracted the data. Trial quality was assessed independently by two reviewers. Missing data were obtained from the authors or estimated. This review analysed 686 children and 375 adults included in 16 trials. Method of delivery of beta2-agonist did not appear to affect hospital admission rates. In adults, the odds ratio of holding chamber versus nebuliser was 1.12, 95% confidence interval 0.45 to 2.76. The odds ratio for children was 0.91, 95% confidence interval 0.4 to 2.1. Children's length of stay in the emergency department was significantly shorter when the holding chamber was used, with a weighted mean difference of -0.62 hours, 95% confidence interval -0.84 to -0.40 hours. Adults' length of stay in the emergency department was similar for the two delivery methods. Peak flow and forced expiratory volume were also similar for the two delivery methods. Pulse rate was lower for holding chamber in children, weighted mean difference -8.3% baseline, 95% confidence interval -11.5 to -5.0,. Metered-dose inhalers with holding chamber produced outcomes that were at least equivalent to nebuliser delivery. Holding chambers may have some advantages compared to nebulisers for children with acute asthma.

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

Background: In asthma exacerbations, higher doses of inhaled beta-agonists are used to overcome acute bronchoconstriction. Traditionally, wet nebulisation has been used, but metered-dose inhaler with a spacer device is an alternative delivery method. Objective: To compare the clinical outcomes in adults and children with acute asthma, presenting in emergency departments or in the community, who have been randomised to beta-agonists given by two different delivery. Methods: a metered-dose inhaler with spacer or a nebuliser. Results: A Cochrane review has found no important differences between the two delivery methods in adults. Children may suffer fewer side effects with spacer delivery. Conclusions: Individual response to treatment cannot be predicted, but many studies overcame this problem by using frequent repeated doses of beta-agonists (one respule via nebuliser or four separate actuations of a metered-dose inhaler through a spacer) every 10–15min, titrated against the clinical response of the patients. This approach is advocated in clinical practice.