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PubMed2005

[Dry powder inhalers in extreme clinical situations].

INTRODUCTION: Dry powder inhalers (DPIs) require a certain threshold of inspiratory effort to generate respirable particles. We undertook a literature review to determine whether this may, in particular clinical settings (young children, elderly subjects, acute or chronic respiratory obstructive syndromes - asthma and COPD), constitute a limitation on their use. STATE OF THE ART: Currently marketed DPIs exhibit different technical characteristics. Many factors may influence their efficacy, so that the predictive utility of in vitro tests is limited. Published clinical studies indicate that aerosol therapies inhaled with DPIs show clinical efficacy even at low inspiratory air flows in adults and children with acute asthma, in acute bronchoconstriction experimentally provoked by methacholine or histamine, in acute asthma attacks in adults and children, and in COPD-related airway obstruction. The efficacy of DPIs appears comparable to that of p-MDIs or nebulisation. However, the studies often have some limitations (including limited statistical power and patient selection) that may affect their value. PERSPECTIVES: The published studies analysed suggest that DPIs may be used in the great majority of clinical situations, subject to careful patient education. Nevertheless, p-MDIs with spacers remain recommended by international guidelines for children under the age of 6. CONCLUSIONS: Additional well-designed clinical studies remain desirable to establish firmly the efficacy of DPIs in these situations.

Anti-Asthmatic Agents↗
PubMed1999

[Comparative studies of particle distribution range of aerosol cromolyn sodium generated by MDI systems].

Particles size distribution of the sodium cromoglycate preparations: CROPOZ PLUS and CROMOGEN EB generated with MDI and for under-pressure releasing methods were measured. Results of measurements indicate a significant repeatability of each sample properties. An average contribution of mass of the respirable fraction for both aerosolized pharmaceuticals is in the range of 40% of the generated dose. CROMOGEN EB with optimizer (spacer) gives a higher contribution of the respirable fraction--up to 50% of dose, with simultaneous lower value of the released mass of aerosol. Particles size distribution of CROPOZ PLUS within a respirable fraction indicates an efficient penetration and deposition of particles in the upper, central and peripheral parts of tracheobronchial tree (TB). High contribution of submicron particles of CROMOGEN EB with optimizer gives efficient penetration and deposition of these particles in the lungs.

Administration, Inhalation↗
PubMed2002

If we prescribe it, will it come? Access to asthma equipment for Medicaid-insured children and adults in the Bronx, NY.

CONTEXT: Asthma is a major cause of morbidity in the United States. Self-management of asthma requires access to appropriate equipment. Clinical experience in an inner-city practice suggests that families encounter difficulties in filling prescriptions for spacers/holding chambers, peak flow (PF) meters, and nebulizer machines. OBJECTIVES: To determine whether Bronx, NY, pharmacies (1) carry spacers/holding chambers, PF meters, and nebulizer machines; (2) accept Medicaid insurance for them; and (3) perceive barriers to reimbursement by Medicaid for this equipment. DESIGN AND SETTING: Structured telephone survey of 100 Bronx pharmacies randomly selected from the 1999 telephone directory. PARTICIPANTS: Ninety-eight pharmacists and 2 pharmacy technicians in 100 different pharmacies. MAIN OUTCOME MEASURES: Pharmacists' reports of equipment availability, Medicaid acceptance, and reasons for not carrying equipment or accepting Medicaid. RESULTS: Overall equipment availability was as follows: spacers (68%), spacers with masks (57%), adult PF meters (40%), child-range PF meters (24%), and nebulizer machines (56%). For Medicaid recipients, equipment was less available: spacers (45%), spacers with masks (35%), adult PF meters (27%), child-range PF meters (17%), and nebulizer machines (33%). Surveyed pharmacists reported misconceptions about requirements for Medicaid reimbursement, which included the following: that Durable Medical Equipment permits are required (64% spacers and 33% PF meters), that special forms are needed (17% PF meters), or that this equipment is not covered by Medicaid (14% spacers and 8% PF meters). Of the 100 surveyed pharmacists, 32 reported difficulties with Medicaid reimbursement and 41 had never tried to receive reimbursement. CONCLUSIONS: These results suggest that (1) access to spacers/holding chambers, PF meters, and nebulizers for Medicaid-insured families is severely limited in Bronx pharmacies; (2) misunderstandings regarding Medicaid reimbursement policies are common; and (3) interventions to increase the proportion of pharmacies that dispense equipment are needed.

Administration, Inhalation↗
PubMed2005

Use of a suspension array for rapid identification of the varieties and genotypes of the Cryptococcus neoformans species complex.

Cryptococcus neoformans is an encapsulated fungal pathogen known to cause severe disease in immunocompromised patients. The disease, cryptococcosis, is mostly acquired by inhalation and can result in a chronic meningoencephalitis, which can be fatal. Here, we describe a molecular method to identify the varieties and genotypic groups within the C. neoformans species complex from culture-based assays. The method employs a novel flow cytometer with a dual laser system that allows the simultaneous detection of different target sequences in a multiplex and high-throughput format. The assay uses a liquid suspension hybridization format with specific oligonucleotide probes that are covalently bound to the surface of fluorescent color-coded microspheres. Biotinylated target amplicons, which hybridized to their complementary probe sequences, are quantified by the addition of the conjugate, streptavidin R-phycoerythrin. In this study we developed and validated eight probes derived from sequence analysis of the intergenic spacer region of the rRNA gene region. The assay proved to be specific and sensitive, allowed discrimination of a 1-bp mismatch with no apparent cross-reactivity, and detected 10(1) to 10(3) genome copies. The described protocol, which can be used directly with yeast cells or isolated DNA, can be undertaken in less than 1 h following PCR amplification and permits identification of species in a multiplex format. In addition to a multiplex capability, the assay allows the simultaneous detection of target sequences in a single reaction. The accuracy, speed, flexibility, and sensitivity of this technology are a few of the advantages that will make this assay useful for the diagnosis of human cryptococcal infections and other pathogenic diseases.

Cryptococcus neoformans↗
PubMed1996

A review and economic evaluation of bronchodilator delivery methods in hospitalized patients.

BACKGROUND: Bronchodilator delivery by metered dose inhaler (MDI) to treat airflow obstruction is considered to be less expensive and as effective as nebulized therapy. OBJECTIVES: To document the utilization of bronchodilator delivery methods in a tertiary care Canadian university teaching hospital and to perform an economic evaluation. METHODS: A prospective 6-week audit of 4 preselected hospital wards (respiratory, thoracic surgery, general surgery, and a general internal medicine clinical teaching unit) and a cost-minimization economic evaluation were performed. Bronchodilator (salbutamol and ipratropium bromide) doses, frequency, and delivery methods, either MDI or wet nebulizer (WN), were recorded for 95 patients treated with aerosolized bronchodilators. Direct costs for medications and hourly wages including benefits and equipment were obtained. Time and motion studies identified time allocated to MDI and WN delivery. We used sensitivity analyses to test assumptions that could significantly affect treatment costs, especially assumptions about medications, labor, and spacer devices. Costs are expressed in Canadian dollars (Can$1 = US$0.75). RESULTS: Sixty-seven patients (70.5%) were treated with WN, 6 (6.3%) with MDI, and 22 (23.2%) with both WN and MDI. Self-administration of salbutamol by MDI was the least expensive: $1.27 for 200-microgram doses and $1.73 for 400-microgram doses compared with $2.62 for a 2.5-mg dose delivered by WN. The difference in cost between equivalent treatments (400-microgram MDI vs 2.5-mg WN) is only $0.89. Sensitivity analyses showed that MDI was the least expensive therapy when self-administration was possible and for all levels of supervision if more than 4 minutes was needed to administer a WN treatment. CONCLUSIONS: Bronchodilator delivery by WN is commonly prescribed for hospitalized patients despite evidence for equivalency of effect using MDI and in the absence of substitution protocols. Previous studies have estimated a far greater cost differential based on unrealistic labor estimates. We found that supervision of patients using MDIs minimized the differential cost between WN and MDI therapy and that cost savings are maximal in patients who can self-administer MDI therapy. Methodologically sound economic evaluations can better identify true cost savings and variables that need further study.

Adolescent↗
PubMed2006

[Effect of intravenous magnesium sulfate on chronic obstructive pulmonary disease exacerbations requiring hospitalization: a randomized placebo-controlled trial].

OBJECTIVE: Magnesium sulfate has been shown to have a bronchodilating effect in asthma, but this effect has not been clearly established in the context of chronic obstructive pulmonary disease (COPD). For this reason we investigated the possible bronchodilating effect of magnesium sulfate in COPD exacerbations. PATIENTS AND METHODS: We studied 24 patients with exacerbated COPD who required admission to our hospital's pneumology department. All patients underwent baseline spirometry and were subsequently randomized to groups in a double-blind crossover design. Patients received 1.5 g of magnesium sulfate or placebo in an intravenous solution for 20 minutes. Those who received magnesium sulfate the first day were given placebo the second day, and vice versa. Spirometry was performed 15, 30, and 45 minutes after administration of magnesium sulfate or placebo. Finally, 400 microg of salbutamol were administered using a spacer and a final spirometry was performed 15 minutes later. All patients also received treatment with corticosteroids, intravenous antibiotics, oxygen, and regularly-scheduled bronchodilator therapy (salbutamol and ipratropium bromide every 6 hours). RESULTS: When we compared absolute increase in milliliters and percentage increase in forced expiratory volume in 1 second (FEV1) obtained with magnesium sulfate application to the increases obtained with placebo after 15, 30, and 45 minutes, no significant differences were found. When we compared absolute and percentage increases in FEV1 after administering salbutamol, we found significantly greater increases after magnesium sulfate administration. The mean (SD) absolute increase in FEV1 was 0.18 [corrected] (0.42) L after magnesium sulfate administration and 0.081 [0.01] L after placebo (P=.004). The percentage increase in FEV1 was 17.11% (3.7%) after magnesium sulfate and 7.06% (1.8%) after placebo (P=.008). CONCLUSIONS: Intravenous administration of magnesium sulfate has no bronchodilating effect in patients with COPD exacerbations. It does, however, enhance the bronchodilating effect of inhaled ss2-agonists.

Acute Disease↗
PubMed1992

Prediction and assessment of flammability hazards associated with metered-dose inhalers containing flammable propellants.

Several potential replacements for chlorofluorocarbons (CFCs) in metered-dose inhalers (MDIs) are flammable. The flammability hazard associated with their use was assessed using a range of MDIs containing 0-100% (w/w) n-butane (flammable) in HFC-134a (non-flammable) fitted with either 25-, 63-, or 100-microliters metering valves or continuous valves. In flame projection tests each MDI was fired horizontally into a flame, and the ignited flume length emitted from the MDI was measured. Flame projections of greater than or equal to 60 cm were produced by all formulations fitted with continuous valves which contained greater than or equal to 40% (w/w) n-butane in HFC-134a. Using metering valves the maximum flame projection obtained was 30 cm. This was observed with a formulation containing 90% (w/w) n-butane in HFC-134a and a 100-microliters valve. For a particular formulation, smaller metering valves produced shorter flame projections. Because many MDIs are used in conjunction with extension devices, the likelihood of accidental propellant vapor ignition was determined in Nebuhaler and Inspirease reservoirs and a Breathancer spacer. Ignition was predictable based on propellant composition, metered volume, number of actuations, and spacer capacity. Calculated n-butane concentrations in excess of the lower flammability limit [LFL; 1.9% (v/v)] but below the upper flammability limit [UFL; 8.5% (v/v)] were usually predictive of flammability following ignition by a glowing nichrome wire mounted inside the extension device. No ignition was predicted or observed following one or two 25-microliters actuations of 100% n-butane into large volume Nebuhaler (750 ml) or Inspirease (660 ml) devices.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosol Propellants↗
PubMed2002

Efficacy and safety of a home-made non-valved spacer for bronchodilator therapy in acute asthma.

UNLABELLED: The aim of this study was to assess the efficacy and safety of an alternative spacer to deliver salbutamol in acute asthma. A prospective randomized study was performed with 196 patients with acute asthma, aged 4-15 y. The clinical features, oxygen saturation (SaO2) and the best of three peak expiratory flow rate (PEFR) measurements were recorded in a standardized questionnaire. Each patient received up to three conventional doses of salbutamol through an alternative home-made non-valved spacer (NVS) (500 ml mineral water plastic bottle) or an oxygen-driven nebulizer (ODN). The clinical and functional respiratory parameters (PEFR and SaO2) were assessed 15 min after each administration of the bronchodilator. In the ODN (n = 99) and NVS (n = 97) groups, PEFR (p > 0.05) and SaO2 (p > 0.05) measurements improved in all stages of the treatment. During the asthma attacks, the ODN group needed a prolonged observation in the emergency room (p = 0.000000). Side effects of salbutamol, e.g. increased heart rate, were observed in 17.2% of the patients in the ODN group and 4.1% in the NVS group (p = 0.003). CONCLUSION: Both devices showed comparable efficacy in mild and moderate acute attacks, but the use of the alternative NVS resulted in a shorter observation period in the emergency room. The frequency of side effects was significantly higher in the ODN group than in the NVS group.

Acute Disease↗
PubMedDate not supplied

Translation squared: improving asthma care for high-disparity populations through a safety net practice-based research network.

To assess the effectiveness of an intervention designed to increase compliance with national asthma care guidelines in primary care safety net health centers serving high-disparity patient populations, we conducted a group-randomized controlled trial (seven intervention sites and nine control sites) in federally funded community health centers in eight southeastern states. There were three components involved in the intervention: resources (asthma kits including peak flow meter, MDI spacer device, plus educational materials), training of all health center staff in asthma care guidelines, and tools or templates for practice-level systems change (asthma flow sheets and standing orders). Control group sites received only copies of the national asthma guidelines. Chart reviews were performed to determine practitioner's compliance with national guidelines for asthma care. Clinicians practicing in intervention health centers showed significantly (p < 0.01) greater improvement on some measures than did the control health centers, although postintervention compliance with guidelines was still suboptimal. Disseminating national guidelines is not enough. Providing training and guideline-specific resources, in combination with tools for practice change, improved care significantly even in safety net health centers serving high-disparity patient populations.

Asthma↗
PubMed1999

Hypothesis: volatile anesthetics produce immobility by acting on two sites approximately five carbon atoms apart.

UNLABELLED: All series of volatile and gaseous compounds contain members that can produce anesthesia, as defined by the minimum alveolar anesthetic concentration (MAC) required to produce immobility in response to a noxious stimulus. For unhalogenated n-alkanes, cycloalkanes, aromatic compounds, and n-alkanols, potency (1 MAC) increases by two-to threefold with each carbon addition in the series (e.g., ethanol is twice as potent as methanol). Total fluorination (perfluorination) of n-alkanes essentially eliminates anesthetic potency: only CF4 is anesthetic (MAC = 66.5 atm), which indicates that fluorine atoms do not directly influence sites of anesthetic action. Fluorine may enhance the anesthetic action of other moieties, such as the hydrogen atom in CHF3 (MAC = 1.60 atm), but, consistent with the notion that the fluorine atoms do not directly influence sites of anesthetic action, adding -(CF2)n moieties does not further increase potency (e.g., CHF2-CF3 MAC = 1.51 atm). Similarly, adding -(CF2)n moieties to perfluorinated alkanols (CH2OH-[CF2]nF) does not increase potency. However, adding a second terminal hydrogen atom (e.g., CHF2-CHF2 or CH2OH-CHF2) produces series in which the addition of each -CF2- "spacer" in the middle of the molecule increases potency two- to threefold, as in each unhalogenated series. This parallel stops at four or five carbon atom chain lengths. Further increases in chain length (i.e., to CHF2[CF2]4CHF2 or CHF2[CF2]5CH2OH) decrease or abolish potency (i.e., a discontinuity arises). This leads to our hypothesis that the anesthetic moieties (-CHF2 and -CH2OH) interact with two distinct, spatially separate, sites. Both sites must be influenced concurrently to produce a maximal anesthetic (immobility) effect. We propose that the maximal potency (i.e., for CHF2[CF2]2CHF2 and CHF2[CF2]3CH2OH) results when the spacing between the anesthetic moieties most closely matches the distance between the two sites of action. This reasoning suggests that a distance equivalent to a four or five carbon atom chain, approximately 5 A, separates the two sites. IMPLICATIONS: Volatile anesthetics may produce immobility by a concurrent action on two sites five carbon atom lengths apart.

Anesthetics, Inhalation↗
PubMed2004

Effect of salbutamol on smoking related cough.

Smokers have an increased prevalence of chronic cough and may complain of exacerbation of cough when attempting smoking cessation. We investigated the use of smokers cough as a model for testing anti-tussive agents. The effect of salbutamol was compared with placebo in healthy adult smokers. In a randomised double blind crossover study the effect of 400 microg salbutamol via MDI plus spacer versus placebo was studied. Cough was assessed before and after the first cigarette of the day (received at 20 minutes) and throughout the day. Cough frequency, citric acid cough challenge, change in cough symptoms and peak flow were recorded. Salbutamol reduced the mean cough frequency between 0 and 20 min. A mean of 4.5 compared to 6 on placebo (p<0.05). A significant reduction in cough followed cigarette consumption in those on placebo. Mean pre-cigarette 6 compared to 3.9 post-cigarette (p<0.02). The citric acid concentration causing two coughs (C2) at 60 min increased on salbutamol. Geometric mean 278.8 compared to 190.4 mM on placebo (p<0.03). Cough frequency is reduced in smokers following a cigarette. The reduction in cough frequency and evoked cough after salbutamol suggests that beta agonists have modest activity in smoking related cough and that smokers cough represents a sensitive model to test anti-tussive activity.

Adult↗
PubMed2000

Is nebulized aerosol treatment necessary in the pediatric emergency department?

BACKGROUND: Infants and small children admitted to the pediatric emergency department (PED) with acute wheezing episodes (AWE) are currently treated with nebulized wet aerosol (NWA). OBJECTIVE: To determine the efficacy of MDI with Nebuchamber (Astra AB; Lund, Sweden), a nonelectrostatic spacer device (NESD), as compared to NWA in the treatment of an unselected population of babies and small children with AWE. DESIGN: Randomized, double-blind, placebo-controlled trial. Forty-two children referred to the PED (median age +/- SD, 16 +/- 15 months) with AWE received either placebo MDI through a NESD (four puffs) and salbutamol 0.5 mL (2.5 mg) as a NWA (group I, n = 19), or salbutamol MDI and 0.5 mL of saline solution administered in the same manner as above (group II, n = 23). This treatment was repeated three times every 20 min. RESULTS: The respiratory rates (RRs) at baseline were as follows: group I, 45 +/- 11.2 breaths/min; and group II, 52.3 +/- 11.3 breaths/min (p = not significant [NS]). After the first, second, and third interventions, the percent fall from baseline of the RR were as follows: group I, 8.9, 13.1, and 17.9%, respectively; group II, 8. 6, 14.6, and 18.6%, respectively. There was no significant difference at any time in the results between the two groups. The clinical scores (CSs) at baseline were as follows: group I, 6.6 +/- 1.3; group II, 6.8 +/- 1.49 (p = NS). After the first, second, and third interventions, the percent fall from baseline of the CS were as follows: group I, 9.1, 17.9, and 23.2%, respectively; group II, 8. 6, 18.9, and 24.7%, respectively. These results, also, did not differ significantly at any time between the two groups. Hospitalization rate and side effects did not differ between the two groups. CONCLUSIONS: We conclude that even in the group of unselected very young children (mean age < 2 years) with AWE, the use of MDI with NESD is at least as effective as the use of NWA. As opposed to data from an adult population, no plateau was reached in the dose-response curve using the above doses over time.

Administration, Inhalation↗
PubMed2001

Aerosol therapy with valved holding chambers in young children: importance of the facemask seal.

OBJECTIVE: Masks are an essential interface between valved holding chambers (VHCs), or spacers, and a small child's face for providing aerosol therapy. Clinical experience suggests that many young children do not cooperate with the VHC treatment or tolerate a mask of any kind. This might impair the mask-face seal and reduce the dose delivered to the child. The objective of this study was to evaluate the ability of parents to provide a good mask-face seal in infants and toddlers using 3 masks provided with commonly used pediatric VHCs and compare this with the seal obtained with the Hans Rudolph pediatric anesthesia mask. METHODS: A preliminary in vitro filter study was conducted to validate the assumption that reduced ventilation as a result of increased facemask leak reduces the drug aerosol dose delivered to the mouth. Facemask leak then was studied in vivo for NebuChamber, AeroChamber, BabyHaler, and Hans Rudolph masks by measuring ventilation with an in-line pneumotachograph while the facemask was held in place by experienced parents who were asked to demonstrate how they deliver medication to their children without any additional instruction. Thirty children (mean age: 3.2 +/- 1.4 years) performed 4 repeat studies with each mask. The first 10 patients performed the tests once again within 1 month. On the second occasion, the parents were coached continuously and encouraged to hold the mask tightly against the child's face. RESULTS: The AeroChamber and Hans Rudolph masks provided the best seal as reflected in the magnitude of the ventilation measured through them. The NebuChamber provided the poorest seal, with 45% less ventilation than the AeroChamber and Hans Rudolph masks. There was considerable intraindividual variability for all masks (24% to 48%); however, the variability with the NebuChamber mask was 2-fold greater than the other masks. All ventilatory volumes during the coached session were significantly greater than during the uncoached session. Variability during the coached session was significantly less (except for the BabyHaler, which remained unchanged). CONCLUSIONS: VHCs with masks designed for use with small children may provide a poor seal with the face, leading to reduced or more variable dose delivery. The facemask seal is critical for efficient aerosol delivery to infants and young children, and this should be stressed to parents.

Administration, Inhalation↗