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PubMed2004

A novel formulation technique for metered dose inhaler (MDI) suspensions.

Metered dose inhalers (MDIs) are a widely used dosage form for pulmonary delivery of anti-asthmatic drugs. However, with the phase-out of chlorofluorocarbon (CFC) propellants and need to switch to the alternative pharmaceutically approved hydrofluoroalkane (HFA) propellants, the MDI formulator was faced with several technical challenges. Product components such as valves and elastomers needed to re-designed, and, due to the limited solubility of the commonly used surfactants in the HFA propellants, novel surfactants were developed or co-solvents were used to bring the conventional surfactants into solution. This paper describes a novel formulation approach for HFA based metered-dose inhalers. A physically stable micro-suspension of the model drug, budesonide, was formulated by an in situ-precipitation process using a hydrophilic stabilizer in the propellant system. A network-like structure of the precipitated drug and excipient was formed and resulted in physically stable suspensions in which the solid phase remained suspended in the propellant system for several weeks. Through life dose uniformity testing of MDI units containing formulations of budesonide produced by the novel process, was consistent and within the limits specified by the FDA draft guidance on metered dose inhalers. The fine particle fraction of the budesonide formulations showed a dependence on formulation composition and aerosol hardware (canister and actuator) illustrating flexibility in optimizing the product using this novel in situ formulation technique.

Chemistry, Pharmaceutical↗

PubMed1997

Pilot study of bronchodilator response to inhaled albuterol delivered by metered-dose inhaler and a novel dry powder inhaler.

BACKGROUND: The metered-dose inhaler is currently one of the most prescribed methods of delivering drugs to the lungs. In the United States, most currently marketed metered dose inhalers use chlorofluorocarbons as the system propellant and require patient breath coordination. These factors lead to the need for a delivery system that is independent of propellants and patient coordination. OBJECTIVE: To compare the magnitude and time course of bronchodilation between albuterol delivered by Ventolin metered dose inhaler and albuterol sulfate powder (Rotacaps) delivered by a novel dry powder inhaler that generates a respirable drug aerosol over a range of inspiratory flow rates. METHODS: A single-center, single-dose, randomized, placebo-controlled, partial-blind, 3-way crossover study was conducted in an outpatient asthma Clinical Research Center. Twelve mild to moderate asthmatic patients 12 to 36 years of age participated in this study that involved three treatments, each separated by three to eight days, consisting of 2 puffs (90 micrograms/puff) albuterol by Ventolin metered-dose inhaler, two inhalations (100 micrograms/puff) albuterol sulfate powder (Rotacaps) by dry powder inhaler, and two inhalations (12.5 mg/inhalation) lactose powder by dry powder inhaler. Spirometry, blood pressure, and heart rate were measured at 30 minutes, 15 minutes, and immediately before treatment and then at 15, 30, 45, 60, 90, 120, 180, 240, and 300 minutes after each treatment. Serum potassium and glucose, and electrocardiograms were measured at 30 minutes before, and 30, 60, 90, and 180 minutes after each treatment. Endpoints were compared with analysis of variance. RESULTS: Five patients (one metered-dose inhaler and four dry powder inhaler) did not respond with > 15% FEV1 increase over baseline within 30 minutes. Metered-dose inhaler and dry powder inhaler mean FEV1 results, respectively, for 11 and 8 responders were 15 minutes in onset, 202.9 and 185.4 minutes in duration, 24.8% and 25.1% maximum change, and 18.6 and 18.2 area-under-FEV1-bronchodilation-curve. Statistical analysis of all patients and responders-only revealed both active treatments to be different from placebo (P = .0018), but not different from each other (P = .1291). No safety endpoints were significantly different among all three treatments (P > .10 for all safety endpoints). CONCLUSIONS: In this study, the dry powder inhaler safely and effectively delivered a commercially available albuterol sulfate powder (Rotacaps) into human lungs with bronchodilation comparable to Ventolin metered-dose inhaler.

Administration, Inhalation↗

PubMed1998

Reservoir design and dose availability with long-term metered dose inhaler corticosteroid use.

The effect of reservoir design and long-term use with inhaled metered dose inhaler (MDI) corticosteroids on aerosol dose availability was examined. Beclomethasone dipropionate (Vanceril) was delivered by MDI with three brands of available reservoir devices: the AeroChamber, the OptiHaler, and the Aerosol Cloud Enhancer (ACE). An in vitro lung model simulated inspiration. Long-term use was simulated by exhausting five MDI canisters of beclomethasone through each sample of reservoir tested. Each canister exhausted through a reservoir represented approximately 1 month of use with one drug. Total inhaled dose was collected at the reservoir mouthpiece and measured using a spectrophotometric assay. Dose delivery was measured before simulated use and after each MDI canister was exhausted through the reservoir. Three samples of each brand were tested with cleaning and three samples were tested without cleaning. With cleaning, the AeroChamber, OptiHaler, and ACE delivered significantly different average doses of 16.6, 10.3, and 8.7 micrograms per MDI actuation, respectively, (P = 0.0017) over time of use. Changes in dose delivery over time of use were not significant (P = 0.2011). Without cleaning, the same three brands averaged 21.1, 9.7, and 7.8 micrograms per MDI actuation, respectively, (P = 0.0019), and changes in dose delivery over time were not significant (P = 0.3265). Reservoir design can affect the delivery of an inhaled corticosteroid, although the delivery over 4 to 5 months remained stable.

Administration, Inhalation↗

PubMed2000

Pharmacokinetics of flunisolide administered via metered dose inhaler with and without a spacer device and following oral administration.

BACKGROUND: After inhalation of a glucocorticoid from a meter dose inhaler (MDI), a certain portion of the delivered dose is deposited in the lungs, and the remainder is deposited in the oropharynx. OBJECTIVE: To examine the absolute bioavailability of flunisolide given orally via metered dose inhaler, and metered dose inhaler with a commercially available spacer device as well as to determine the fraction of drug deposited in the lungs following inhalation. METHODS: Twenty-four healthy volunteers were enrolled in the study; twenty-two completed the study. The IRB approved the study protocol, and informed consent was obtained. Volunteers received four treatments: treatment A (MDI), 1.0 mg inhaled flunisolide; treatment B (MDI-S), 1.0 mg inhaled flunisolide with a spacer device; treatment C, 1.0 mg of orally administered flunisolide with 240 mL of water; and treatment D, 1.0 mg intravenous flunisolide by IV push in the antecubital vein over 60 seconds. Plasma and urine flunisolide were quantified by HPLC/mass spectrometry/mass spectrometry. RESULTS: Flunisolide is a corticosteroid with low oral bioavailability (6.7%), which was found to be lower than previously reported. Similar AUCs were observed between the MDI and MDI-S groups, but by using mass balance equations, it appears that more flunisolide was delivered to the lungs in the MDI-S group (410 microg versus 280 microg). Oropharyngeal deposition was an important difference between the two inhaler groups. Approximately an 11-fold reduction in the oropharyngeal deposition of flunisolide through use of the spacer device was observed. CONCLUSIONS: Use of a spacer device improved pulmonary delivery of flunisolide by almost 50% and significantly decreased the oropharyngeal exposure to drug.

Administration, Oral↗

PubMed1987

Evaluation of inhalation aids of metered dose inhalers in asthmatic children.

Many patients have incorrect aerosol inhalation technique with metered dose inhalers (MDI). Several inhalation aids have been developed and marketed for these patients. Even those who have correct inhalation technique may benefit from these devices. We compared bronchodilator efficacy of two puffs of albuterol aerosol administered either directly from a MDI mouthpiece, or from an inhalation aid (InspirEase, Aerochamber, Aerosol Bag) in 20 children who had previously demonstrated proper inhalation technique. The children received two puffs of aerosol from a MDI in each of two modalities tested each day on four different days (double blind). One modality contained albuterol aerosol and the other placebo. Pulmonary function was tested before and at 15, 30, 60, 120, and 180 minutes after treatment. Forced expiratory volume in 1 second (FEV1) increased similarly after all four modes of administration. Six patients who had incorrect inhalation technique benefited from the three inhalation aids. The aerosol bag and InspirEase produced slightly greater bronchodilator response than the Aerochamber. The inhalation aids are useful devices for those who have incorrect inhalation technique, but those who have correct technique do not derive any benefit from these devices.

Adolescent↗

PubMed1998

Influence of temperature on the emitted dose of an oral metered dose inhaler.

The performance of metered dose inhalers is critical for the efficient delivery of drugs to the intended site of deposition in the respiratory tract. The temperature at which metered dose inhaler products are used by patients may influence the physicochemical characteristics of the emitted dose. Product performance characteristics of a metered dose inhaler containing beclomethasone dipropionate and oleic acid in a blend of chlorofluorocarbon propellants, Freon-11 and Freon-12, were determined by cascade impaction analysis and dose delivery through the valve after the metering chamber was loaded and actuated at 4 degrees C, 23 degrees C, and 40 degrees C. The dose delivered from the valve was not affected by the temperature at which the metering chamber was loaded and actuated. The mass median aerodynamic particle size of the emitted aerosol decreased and the percentage respirable fraction increased as the temperature was increased. The geometric standard deviation of the particle size distribution was not significantly affected by the temperature at which the metering chamber was loaded and actuated. The temperature at which a metered dose inhaler is used by a patient may influence the amount of drug that is potentially respirable; therefore, the dose expected to be delivered and the corresponding therapeutic effect may also be affected.

Administration, Inhalation↗

PubMed1990

Comparison of bronchodilator responses and deposition patterns of salbutamol inhaled from a pressurised metered dose inhaler, as a dry powder, and as a nebulised solution.

The lung dose and deposition patterns of drug delivered by dry powder inhaler are not known. The effects of inhaling 400 micrograms salbutamol delivered by dry powder inhaler (two 200 micrograms salbutamol Rotacaps), by pressurised metered dose inhaler, and by Acorn nebuliser were studied in nine subjects with chronic stable asthma. Technetium-99m labelled Teflon particles were mixed with micronised salbutamol in the pressurised metered dose inhaler and in the capsules; technetium-99m labelled human serum albumin was mixed with the salbutamol solution for the nebuliser study. The pressurised metered dose inhaler deposited 11.2% (SEM 0.8%) of the dose within the lungs; this was significantly more than the dose deposited by the dry powder inhaler (9.1% (0.6%], but did not differ significantly from the dose delivered by the nebuliser (9.9% (0.7%]. Distribution within the peripheral third of the lung was significantly greater with the nebuliser than with the other two systems; FEV1 improved to a significantly greater extent after inhalation of 400 micrograms salbutamol from the pressurised metered dose inhaler (35.6% from baseline) than from the nebuliser (25.8%) or dry powder inhaler (25.2%). Thus after inhalation of similar doses of salbutamol a larger proportion of drug was deposited within the lungs when it was inhaled from a metered dose inhaler than from a dry powder system; the nebuliser achieved the greatest peripheral deposition. The bronchodilator response seems to depend on the amount of drug within the lungs rather than its pattern of distribution.

Administration, Inhalation↗

PubMed2003

Fenoterol delivery by Respimat soft mist inhaler versus CFC metered dose inhaler: cumulative dose-response study in asthma patients.

OBJECTIVES: Respimat (RMT) soft mist inhaler (SMI) is a novel, propellant-free alternative to chlorofluorocarbon metered-dose inhalers (CFC-MDIs). The aim of this study was to evaluate the safety and establish the equipotent dose of fenoterol delivered by RMT SMI vs. a conventional MDI. DESIGN: Double-blind, randomized, crossover, comparative study between fenoterol inhaled via RMT (either 50 microg/actuation, RMT50; or 100 microg/actuation. RMT100) and MDI (100 microg/actuation; MDI100). PATIENTS AND INTERVENTIONS: A total of 41 asthma patients received cumulative doses of fenoterol 600 microg (RMT50) or 1200 microg (RMT100 and MDI100) on 3 test days. MEASUREMENTS AND RESULTS: The bronchodilator response (forced expiratory volume in 1 second [FEV1]) was considered therapeutically equivalent (i.e., noninferior) if the 95% confidence intervals for the difference in their mean changes from baseline were within limits of +/- 0.15L. Systemic exposure was evaluated from plasma fenoterol levels. Adverse events (AEs) were recorded. RMT50 and RMT100 produced noninferior bronchodilatation to MDI100 from 30minutes after the first dose. RMT50 showed equivalent safety and tolerability to MDI100, whereas RMT100 produced a higher incidence of AEs, a significantly greater plasma potassium reduction and a significant increase in pulse rate. Fenoterol plasma levels were twice as high with RMT100 as with RMT50 or MDI100. CONCLUSIONS; The nominal dose of fenoterol administered via RMT SMI can be at least halved to achieve equivalent efficacy, safety, and tolerability to a MDI.

Administration, Inhalation↗

PubMed1994

Easyhaler, a novel multiple dose powder inhaler: clinically equivalent to salbutamol metered dose inhaler and easier to use.

Twenty-one adult asthmatic patients participated in a trial to compare the clinical equivalence of a single dose of salbutamol inhaled either from a novel multiple dose powder inhaler (MDPI), Easyhaler, or from a conventional metered dose inhaler (MDI). The trial was carried out as a randomized, double-blind, crossover study. The study involved 2 study days with a 6-hour follow-up period of spirometric indices. In addition, blood pressure and heart rate were measured immediately before each lung function test. Our data indicate that salbutamol treatment with the MDPI achieves values which are equivalent to those achieved with the conventional pressurized MDI as regards improving pulmonary function and tolerability. The mean maximum forced expiratory volume in 1 s (FEV1) after the powder dose was 2.44 +/- 0.96 liters and after the aerosol dose 2.45 +/- 0.93 liters. The mean area under the curve of absolute FEV1 values was 822 +/- 340 and 829 +/- 335, respectively. The mean percent change from the baseline in FEV1, forced vital capacity and peak expiratory flow following administration of the preparations was of equal magnitude in both cases. The treatments tested had no effect on blood pressure or heart rate and were well tolerated. A further important finding was that most patients found the MDPI easier or no more difficult to use than the conventional MDI and this probably facilitates the transition from pressurized MDIs to the novel MDPI.

Adult↗

PubMed2001

Selecting an accessory device with a metered-dose inhaler: variable influence of accessory devices on fine particle dose, throat deposition, and drug delivery with asynchronous actuation from a metered-dose inhaler.

Accessory devices reduce common problems with metered-dose inhalers (MDIs), namely high oropharyngeal deposition of aerosol and incoordination between actuation and inhalation by the patient. The objective of this study was to systematically compare the performance of various accessory devices in vitro. MDIs were tested alone or in combination with four spacers (Toilet paper roll, Ellipse, Optihaler, Myst Assist) and five holding chambers (Aerochamber, Optichamber, Aerosol Cloud Enhancer, Medispacer, and Inspirease). An Anderson cascade impactor was used to measure aerosol mass median aerodynamic diameter (MMAD) and fine particle dose (MMAD < 4.7 microm). In separate experiments, the influence of asynchronous MDI actuation on drug delivery was determined with a simulated spontaneous breathing model. Compared with the MDI alone, all of the accessory devices reduced aerosol MMAD and increased lung-throat ratio (fine particle dose/throat impaction; p < 0.05 for both parameters). The fine particle dose of albuterol was 40% higher with the Ellipse (p < 0.01), was equivalent with the Toilet Paper Roll, Aerochamber, Optichamber, and Medispacer, and was 33-56% lower with the Optihaler, Myst Assist, Aerosol Cloud Enhancer, and Inspirease (p < 0.03). MDI actuation in synchrony with inspiration produced highest drug delivery; when MDI actuation occurred 1-sec before inspiration or during exhalation, decrease in drug delivery with holding chambers (10-40% reduction) was less than that with spacers (40-90% reduction). Accessory device selection is complicated by variability in performance between devices, and in the performance of each device in different clinical settings. In vitro characterization of a MDI and accessory device could guide appropriate device selection in various clinical settings.

Albuterol↗

PubMed1986

What determines whether an elderly patient can use a metered dose inhaler correctly?

The metered dose inhaler (MDI) technique of 30 elderly patients (mean age 79.9 years) was assessed. Sixty per cent were competent, though only 10% had an ideal technique; 40% were incompetent. Inadequate timing of actuation and inhalation was the most frequent error made. Competence was significantly related to mental status questionnaire (MSQ) scores of 7/10 or more. Patients who were first prescribed an MDI in hospital were significantly more likely to be competent than those prescribed an MDI by the general practitioner. Competence was not related to age, underlying diagnosis or duration of MDI therapy. Elderly patients requiring MDI therapy should be carefully selected and properly instructed by the prescribing doctor.

Aerosols↗

PubMed1993

Small bore nozzle extensions to improve the delivery efficiency of drugs from metered dose inhalers: laboratory evaluation.

Metered dose inhalers (MDIs) are frequently used to supply aerosolized drugs, particularly bronchodilators, to the tracheobronchial tree of patients with endotracheal tubes in the intensive care unit or in the operating room. The efficiency of delivery to the lungs of agents such as the beta 2-adrenergic agonists is known to be low. In an in vitro model, we evaluated a means of improving the delivery of drug released from an MDI beyond the distal tip of the endotracheal tube. Extensions of the MDI nozzle were fashioned from modified intravenous catheters or sections of small bore polyethylene tubing. A model trachea/carina was constructed and suspended above a collecting device. An albuterol MDI was actuated through the nozzle extension and into the model airway. We measured the quantity of albuterol deposited in the nozzle extension, in the trachea/carina and in the distal collecting device. Particle size distribution was determined with a cascade impactor. The results indicate an inverse relationship between the quantity of drug delivered distally and the inner diameter of the nozzle extension, with a marked increase in delivery for an inner diameter < 1 mm. Ninety percent of the actuated dose from the MDI exited a 0.76-mm inner diameter nozzle extension. From 20 to 30% of the nominal MDI dose was recovered from the distal collector, 70% of which deposited in the particle size range of 1 to 5 microns. Deposition in the trachea/carina was high, but this was reduced by introducing a flare in the tip of the nozzle extension, which did not affect the dose reaching the distal collector.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗

PubMed2003

Comparative efficacy of terbutaline sulphate delivered by Turbuhaler dry powder inhaler or pressurised metered dose inhaler with Nebuhaler spacer in children during an acute asthmatic episode.

AIMS: To compare the efficacy of terbutaline sulphate delivered via Turbuhaler with a pressurised metered dose inhaler (pMDI) connected to Nebuhaler spacer in a population of asthmatic children presenting to emergency departments because of an acute episode of asthma. METHODS: Randomised double blind, double dummy, parallel study of acute asthma in the emergency department. A total of 112 children (6-16 years), who had a diagnosis of asthma, a baseline FEV1 of 25-60% of predicted normal value (PNV), and the ability to perform spirometry were studied. Patients received two doses of 0.5 mg/10 kg (maximum 2.0 mg) of terbutaline sulphate at time 0 minutes and time 30 minutes. The two groups were also stratified into subgroups based on FEV1: 25-45% and 45.1-60% PNV. FEV1 before treatment and at two 15-minute intervals after each treatment was the main outcome measure. PIF, PEF, heart rate, SpO2, and tremor were also measured at these times. RESULTS: Both the Turbuhaler and pMDI+Nebuhaler groups showed significant increases from baseline to final value in their FEV1 results, 49% and 50% change from baseline to t = 60 min, respectively (p < 0.001) using last value carried forward. No significant difference was found between the two groups for these results. Subanalysis of the stratified groups revealed similar results. In addition, no significant difference was found in the group and subgroup comparisons for heart rate, SpO2, and tremor. CONCLUSION: Results show that Turbuhaler and pMDI+Nebuhaler are similar in terms of benefit and side effects in the treatment of acute moderate to severe asthma attacks in this study population.

Acute Disease↗

PubMed2002

Adrenal suppression in asthmatic children receiving low-dose inhaled budesonide: comparison between dry powder inhaler and pressurized metered-dose inhaler attached to a spacer.

BACKGROUND: Dry powder inhalers (DPI) have in recent years become a common mode for administration of inhaled corticosteroids for preventive therapy of asthma. Inhaled steroids delivered by DPI achieve increased lung deposition compared with pressurized metered-dose inhalers (pMDI), which is associated with increased therapeutic effect. This may be associated with increased systemic absorption. OBJECTIVE: The purpose of this study was to evaluate the prevalence of adrenal suppression in children using low-dose budesonide given by DPI, as compared with pMDI attached to a large-volume spacer device (pMDI + spacer). METHODS: In an open-labeled crossover study, 15 asthmatic children aged 5 to 15 years received 200 microg of inhaled budesonide twice daily by DPI (Turbuhaler, Astra, Draco AB, Lund, Sweden) and by pMDI + spacer, 1 month each, in a randomized order. Twenty-four-hour urine collections were performed at baseline and at the end of each of the 2 months of the study period, and urinary cortisol and creatinine were measured. RESULTS: Baseline urinary cortisol:creatinine was 0.038 +/- 0.012 microg/mg, similar in both groups. After 1 month of DPI therapy, urinary cortisol:creatinine was reduced by 27 +/- 16% to 0.028 +/- 0.012 microg/mg (P = 0.018). Urinary cortisol:creatinine after 1 month of pMDI + spacer therapy was similar to baseline 0.037 +/- 0.019 microg/mg (P = 0.78). CONCLUSIONS: Treatment of asthmatic children with budesonide 400 microg daily given via a DPI for 1 month was associated with hypothalamic-pituitary-adrenal axis suppression. This effect was not observed with the same dose of budesonide administered via pMDI + spacer. This indicates that systemic absorption might be reduced with pMDI + spacer therapy.

Absorption↗

PubMed1999

Therapeutic equivalence of Spiros dry powder inhaler and Ventolin metered dose inhaler. A bioassay using methacholine.

Because chlorofluorocarbons (CFCs) contribute to depletion of stratospheric ozone, CFC-containing metered-dose inhalers (MDIs) such as Ventolin and Proventil are being phased out of production. In terms of delivery of albuterol to the lungs, we compared an alternative delivery system, the Spiros dry-powder inhaler (DPI), with Ventolin, using a methacholine challenge-based clinical bioassay. Twenty-four adults and adolescents with asthma completed this double-blind, four-period crossover study. Doses evaluated were one and three actuations each of Spiros and Ventolin (90- and 270-microgram albuterol base). A methacholine challenge (Cockcroft method) was initiated 3 h before and 0.25 h after albuterol. Predose PC(20)FEV(1) values were not significantly different between study days. Postdose PC(20)FEV(1) results met standard bioassay study validity criteria: i.e., a significant dose-response relationship was present (p = 0.0002); tests for deviation from parallelism and overlap of dose-response curves were nonsignificant (p = 0.08, 0.69). By using Finney 2-by-2 bioassay analysis, we estimate that each Spiros actuation delivers 1.12 times as much albuterol to the airways as one Ventolin actuation (90% confidence interval, 0.68 to 1.94). There were no significant differences in markers of systemic effects (vital signs, potassium, and blood glucose concentrations). We conclude that Spiros and Ventolin inhalers deliver comparable quantities of albuterol to the airways.

Adolescent↗

PubMed2005

Comparison of the aerosol velocity and spray duration of Respimat Soft Mist inhaler and pressurized metered dose inhalers.

Apart from particle size distribution, spray velocity is one of the most important aerosol characteristics that influence lung deposition of inhaled drugs. The time period over which the aerosol is released (spray duration) is also important for coordination of inhalation. Respimat Soft Mist Inhaler (SMI) is a new generation, propellant-free inhaler that delivers drug to the lung much more efficiently than pressurised metered dose inhalers (pMDIs). The objective of this study was to compare the velocity and spray duration of aerosol clouds produced by Respimat SMI with those from a variety of chlorofluorocarbon (CFC) and hydrofluoroalkane (HFA) pMDIs. All inhalers contained solutions or suspensions of bronchodilators. A videorecording method was used to determine the aerosol velocity. For spray duration, the time for generation of the Soft Mist by Respimat SMI was initially determined using three different methods (videorecording [techniques A and B], laser light diffraction and rotating disc). Videorecording was then used to compare the spray duration of Respimat SMI with those from the other inhalers. The Soft Mist produced by Respimat SMI moved much more slowly and had a more prolonged duration than aerosol clouds from pMDIs (mean velocity at a 10-cm distance from the nozzle: Respimat SMI, 0.8 m/sec; pMDIs, 2.0-8.4 m/sec; mean duration: Respimat SMI, 1.5 sec; pMDIs, 0.15-0.36 sec). These characteristics should result in improved lung and reduced oropharyngeal deposition, and are likely to simplify coordination of inhaler actuation and inhalation compared with pMDIs.

Aerosol Propellants↗

PubMed1994

Medical personnel's knowledge of and ability to use inhaling devices. Metered-dose inhalers, spacing chambers, and breath-actuated dry powder inhalers.

BACKGROUND: Current treatment strategies for asthma and chronic obstructive pulmonary disease (COPD) emphasize the inhalation route, yet patients often misuse metered-dose inhalers (MDI). To address this problem, patient education by medical personnel has been recommended and a variety of alternate inhaler devices have been developed. METHODS: We surveyed medical personnel to assess their knowledge of and ability to use three widely used inhaler devices; MDI, MDI with a spacing chamber (Aerochamber, Trudell Medical, Canada), and a breath-actuated multidose dry powder inhaler (Turbuhaler, Astra Pharmacy, Inc., Conada). Thirty respiratory therapists (RT), 30 registered nurses (RN), and 30 medical house staff physicians (MD) were asked to demonstrate the use of each device using placebo inhalers and to answer 11 clinically relevant questions related to the use and maintenance of the tested devices. RESULTS: The RT's percent mean knowledge score (67 +/- 5 percent) was significantly higher than those achieved by either the RNs (39 +/- 7 percent) or the MDs (48 +/- 7 percent) (for all p < 0.0001). Similarly, percent mean demonstration scores for each device were significantly higher for RTs than either RN or MD groups; for MDI, 97 +/- 3 percent versus 82 +/- 13 percent and 69 +/- 24 percent, respectively (p < 0.0001); for the Aerochamber, 98 +/- 2 percent versus 78 +/- 20 percent and 57 +/- 31 percent (p < 0.0001); and for the Turbuhaler, 60 +/- 30 percent versus 12 +/- 23 percent and 21 +/- 30 percent (p < 0.0001). Knowledge of and practical skills with the devices were roughly proportional to the length of time the device had been in clinical use, Turbuhaler demonstration scores being lower than either MDI or Aerochamber scores (p = 0.05 and p = 0.09, respectively). More RTs (77 percent) had received formal instruction on the use of devices at school than either RNs (30 percent) or MDS (43 percent) (p < 0.05). CONCLUSION: We conclude that (1) many medical personnel responsible for monitoring and instructing patients in optimal inhaler use lack rudimentary skills with these devices, (2) nurses and physicians seldom receive formal training in the use of inhaling devices, and (3) newer inhaling devices designed to obviate problems of technique are at present less likely to be used well by medical personnel soon after their introduction.

Clinical Competence↗

PubMed2005

Inhalation therapy with metered-dose inhalers and dry powder inhalers in mechanically ventilated patients.

Pressurized metered-dose inhalers (pMDIs) are commonly employed for administering bronchodilator aerosols to mechanically ventilated patients. Although it is feasible to employ dry powder inhalers in ventilator circuits, the presence of humidity in the ventilator circuit could reduce their efficiency. A complex array of factors influence drug delivery from pMDIs during mechanical ventilation, and subtle differences in the method of administration can markedly alter aerosol deposition in the lower respiratory tract. However, when the technique of administration is optimized, the efficiency of drug delivery from pMDIs in mechanically ventilated patients is comparable to that in ambulatory patients. Significant bronchodilator effects are observed with as few as 4 puffs from a pMDI and cylindrical spacer. In mechanically ventilated patients, pMDIs are a cost-effective, convenient, and safe method for delivering bronchodilator aerosols.

Administration, Inhalation↗