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Pressurised metered-dose inhalers versus all other hand-held inhalers devices to deliver bronchodilators for chronic obstructive pulmonary disease.

BACKGROUND: Bronchodilator therapy for COPD may be delivered by a number of different inhaler devices. OBJECTIVES: To determine the efficacy of pressurised metered dose inhalers (pMDI) compared to any other handheld inhaler device for the delivery of bronchodilators in non-acute COPD. SEARCH STRATEGY: The Cochrane Collaboration, Asthma and Wheeze Randomised Controlled Clinical Trials register was searched for studies. The UK pharmaceutical companies who manufacture inhaled COPD medication were also contacted. SELECTION CRITERIA: Two reviewers independently reviewed the results of computerised search and any potentially relevant articles were obtained in full. DATA COLLECTION AND ANALYSIS: One reviewer extracted details of each trial and a second reviewer checked all extracted data. Dichotomous outcomes such as exacerbation rate were assessed using relative risk, with 95% confidence interval (CI). MAIN RESULTS: Fourteen studies appeared potentially relevant but only three studies (61 patients) met the entry criteria. Two studies compared a dry powder device (Turbuhaler or Rotahaler) with a pMDI for beta2-agonist delivery, and one (36 patients cross-over design) the Respimat (soft mist device for ipratropium) vs a pMDI. For the Turbuhaler and Rotahaler, none of the reported outcome measures were significantly different. The Rotahaler study used a high and low dose of medication with or without large volume spacer. The study using the Respimat showed significant increases in FEV1 when compared to a pMDI (difference in change from base line 70 ml, 95% CI 10, 130 ml). The effect on change in FVC was of similar size. There were no differences between these two devices for any other reported outcomes. Although none of the included studies required prior patient ability to use any of the inhalers (and no study mentioned device training), it was assumed that all patients randomised into the study would have undergone training in use of the study inhalers and were capable of using those devices. REVIEWER'S CONCLUSIONS: In patients with stable COPD, pMDI produced similar outcomes to a dry powder device for delivering beta2-agonists, but the very small number of studies and included patients does not permit firm conclusions to be drawn. The soft mist device for ipratropium was more effective than a pMDI, but the data come from one small study. There need to be further well designed randomised controlled trials to define the role of inhaler devices using bronchodilators in stable COPD.

Adrenergic Agonists↗

Clinical comparability between the CFC and HFA budesonide pressurised metered-dose inhalers in paediatric patients with asthma: a randomised controlled trial.

OBJECTIVE: To evaluate the efficacy and tolerability of a novel hydrofluoroalkane (HFA) pressurised metered dose inhaler (pMDI) formulation of budesonide (Pulmicort) versus the conventional chlorofluorocarbon (CFC) pMDI formulation in paediatric patients with asthma. METHODS: This was a Phase III, multicentre, 12-week, double-blind, randomised, parallel-group study involving children (6-12 years of age) with mild to moderate asthma. Patients received either budesonide HFA pMDI or budesonide CFC pMDI 200 mug twice daily, with or without a spacer (NebuChamber/Nebunette). Primary efficacy endpoint: mean percentage change in forced expiratory volume in 1 second (FEV(1)) from baseline to week 12. Secondary efficacy endpoints included changes in FEV(1) per cent of predicted normal, forced vital capacity, morning and evening peak expiratory flow rate, asthma symptoms and use of rescue medication. RESULTS: A total of 159 patients received treatment (HFA 77, CFC 82). For mean percentage change in FEV(1) from baseline to week 12, the difference between the treatments (CFC pMDI - HFA pMDI) was -3.1% (95% confidence interval [CI] -8.0% to 1.8%) for the full analysis set and was not affected by spacer use. The upper CI was < 10% (the predefined non-inferiority margin), so non-inferiority was demonstrated. Improvements in the secondary efficacy endpoints with both budesonide formulations were not significantly different. In both groups there were similar numbers of adverse events and no evidence of oral candidiasis at week 12. CONCLUSIONS: Treatment with budesonide HFA pMDI is effective and well tolerated in children with asthma and is clinically comparable to budesonide CFC pMDI.

Aerosol Propellants↗

[Influence of inhaled glucocorticoids on bone mineral density and bone metabolism].

Inhaled glucocorticoids (IGs) are today the first-line treatment for bronchial asthma. The systemic effects of inhaled glucocorticoids, such as suppressing the hypothalamic-pituitary-adrenal axis, are generally less than those with oral glucocorticoids. However, there is a long-term risk of adverse effects on bone. The objective of this piece was to review the published data on the effects of IGs on bone metabolism markers and bone mineral density in adults and in pediatric patients. The reviewed studies do not provide uniform results. Nevertheless, in general they suggest that IGs can affect metabolism and bone mineral density, especially: 1) when high doses are administered (more than 400 micrograms/day in children and more than 800 micrograms/day in adults), 2) in pediatric patients, in whom growth in stature can also be affected, 3) in patients whose intake of calcium and vitamin D is inadequate, and 4) in postmenopausal women not undergoing hormone replacement therapy. In general, at therapeutically equivalent doses, beclomethasone has a greater deleterious effect on bone than does budesonide, which in turn has more of an effect than does fluticasone. In addition to the obvious precaution of using the lowest effective dose, other proposed preventive measures include: 1) adequate instruction on the use of aerosols, 2) the use of large volume spacer devices, 3) rinsing the mouth after administering IGs, and 4) dietary adjustments or supplements in order to ensure an adequate intake of calcium and vitamin D.

Administration, Inhalation↗

Meter-dosed, inhaled beclomethasone initiated at birth to prevent bronchopulmonary dysplasia.

OBJECTIVE: To examine the hypothesis that meter-dosed, inhaled beclomethasone administered to premature infants, beginning at birth and continuing in a tapering dosage schedule over the first 12 days of life, decreases the occurrence of bronchopulmonary dysplasia (BPD), at 36 wks corrected gestational age. DESIGN: Prospective, randomized, double-blind, placebo-controlled, small pilot clinical trial. SETTING: Tertiary care, neonatal intensive care unit. PATIENTS: Premature low birth weight neonates (<or=1300 g) followed from birth until 36 wks corrected gestational age. INTERVENTIONS: Aerosolized beclomethasone dipropionate was administered in a tapering dosage schedule beginning at birth and extended for the first 12 days of life, utilizing an aerosol spacer chamber and manual hand ventilation. In a subset of the subjects, a cosyntropin stimulation test was conducted on day 13 to ascertain potential hypothalamic-pituitary-adrenal axis suppression. Need for mechanical ventilation/continuous positive airway pressure (CPAP) and/or oxygen was assessed at 30 days of life and 36 wks corrected gestational age in addition to a number of other variables clinically relevant to the development of BPD. MEASUREMENTS AND MAIN RESULTS: In total, 19 placebo-treated and 20 beclomethasone-treated infants completed the study. Inhaled beclomethasone significantly reduced the need for supplemental oxygen at 30 days (p =.005) of life but not at 36 wks corrected gestational age (p =.243). A significantly greater proportion of infants receiving beclomethasone were extubated before 2 wks of age (p =.035), and infants receiving beclomethasone required significantly fewer days of mechanical ventilation (p =.004), but increased days of nasal CPAP as compared with the control group. Although fewer beclomethasone-treated than placebo-treated infants were administered intravenous steroids after 2 wks of age, this difference was not significant. No differences between groups were noted for the diagnoses of retinopathy of prematurity, nosocomial infection, or intraventricular hemorrhage. Similarly, no differences in the cosyntropin stimulation test were ascertained between treated and nontreated infants. No adverse effects were attributable to inhaled beclomethasone. CONCLUSIONS: In this small series, inhaled beclomethasone initiated at birth did not reduce the occurrence of BPD as defined by the continued requirement for supplemental oxygen at 36 wks corrected gestational age. However, inhaled beclomethasone did reduce the need for supplemental oxygen at 30 days of life and appeared to facilitate the transition from intubation/mechanical ventilation to less invasive nasal CPAP, as demonstrated by more frequent extubation before 2 wks of age and decreased total duration of mechanical ventilation in the beclomethasone-treated group. No adverse effects, including adrenal suppression, were noted in infants treated with inhaled beclomethasone. On the basis of the safety and apparent effectiveness of early inhaled beclomethasone in reducing the need for invasive mechanical ventilation and supplemental oxygen during the first month of life in premature infants, a larger clinical trial with greater power is warranted to ascertain if early inhaled beclomethasone can attenuate the occurrence of BPD.

Clinical Trial↗

Effects of formoterol (Oxis Turbuhaler) and ipratropium on exercise capacity in patients with COPD.

Although long-acting inhaled beta 2-agonists improve various outcome measures in COPD, no double-blind study has yet shown a significant effect of these drugs on exercise capacity. In a randomized, double-blind, placebo-controlled, crossover study, patients received formoterol (4, 5, 9, or 18 micrograms b.i.d. via Turbuhaler), ipratropium bromide (80 micrograms t.i.d. via pMDI with spacer), or placebo for 1 week. Main endpoint was time to exhaustion (TTE) in an incremental cycle ergometer test. Secondary endpoints were Borg dyspnoea score during exercise, lung function, and adverse events. Thirty-four patients with COPD were included, mean age 64.8 years, FEV1 55.6% predicted, reversibility 6.1% predicted. All doses of formoterol, and ipratropium significantly improved TTE, FEV1, FEF25-75%, FRC, IVC, RV and sGAW compared with placebo. A negative dose-response relationship was observed with formoterol. Ipratropium increased time to exhaustion more compared with formoterol, 18 micrograms, but not with formoterol, 4.5 and 9 micrograms. No changes in Borg score were found. There was no difference in the adverse event profile between treatments. In conclusion, 1 week of treatment with formoterol and ipratropium significantly improved exercise capacity and lung function compared with placebo. However, a negative dose-response relation for formoterol was unexpected and needs further investigation.

Administration, Inhalation↗

Determining factors of aerosol deposition for four pMDI-spacer combinations in an infant upper airway model.

The aim of this study was to measure and compare the influence of tidal volume (Vt) respiratory rate (RR) and pMDI/spacer combination on aerosol deposition of 4 pMDI/spacer combinations, which are used for infants. An anatomically correct upper airway model of a 9-month-old infant was connected to a breathing simulator. Sinusoidal breathing patterns were simulated with; duty cycle T(i)/T(tot) = 0.42, Vt: 25, 50, 75, 100, 150, 200 ml (RR: 30 breaths/min); and RR: 20, 30, 42, 60, 78 breaths/min (Vt: 100 mL). pMDI/Spacers tested were: budesonide 200 microg/Nebuchamber, fluticasone 125 microg/Babyhaler and both budesonide and fluticasone with Aerochamber. Plastic spacers were detergent coated to reduce electrostatic charge. Spacer-output and lung dose were measured by a filter positioned between spacer and facemask or between model and breathing simulator. Particle size distribution of lung dose was assessed with an impactor during simulated breathing. Spacer-output was significantly positively correlated with Vt for all pMDI/spacers (all R > 0.77, p < 0.001), but not correlated with RR. Lung doses initially increased from Vt = 25 to 50 mL (Nebuchamber, Aerochamber) or to 100 mL (Babyhaler) and then decreased, with increasing Vt and RR (R: -0.98 to -0.82, p < 0.001). Lung doses of fluticasone were 1.5-6-fold higher compared with budesonide, irrespective of spacer type (p < 0.001). MMAD decreased with increasing Vt and RR. Dose to the lungs of particles <2.1 microm was independent of Vt and RR. Lung dose decreases with increasing inspiratory flow (increasing Vt or RR) by increasing impaction of coarse particles in the upper airways. Deposition of particles <2.1 microm is relatively flow independent. When electrostatic charge of spacers is reduced, lung dose is pMDI dependent and spacer independent.

Aerosols↗

[Analysis of causes of incorrect use of dose aerosols].

Preparations administered by inhalation make relatively high demands on the skill and knowledge of the patient in handling this form of application, for the effectivity of the therapy is inseparably linked to its faultless application. The present article aims at analysing possible mistakes in handling and at finding the most effective way of avoiding them. Several groups of patients with different previous knowledge were analysed in respect of handling skill and the influence of training on an improvement of the same; the patients' self-assessment was analysed by questioning them. Most mistakes are committed by patients whose only information consists of the contents of the package circular. Written instructions alone cannot convey sufficient information especially on how to synchronize the release operations. Major mistakes are insufficient expiration before application in 85.6% of the patients and lack of synchronisation in 55.9%, while the lowest rate of errors in respect of handling was seen in patients who had undergone training and instruction. Training in application associated with demonstration and subsequent exercise reduces the error ratio to a tolerable level. Pulverizers free from propelling gas and preparations applied by means of a spacer are clearly superior to others in respect of a comparatively low error rate. 99.3% of all patients believe they are correctly following the instructions, but on going into the question more deeply it becomes apparent that 37.1% of them make incorrect statements. Hence, practical training in application should get top priority in the treatment of obstructive diseases of the airways. The individual steps of inhalation technique must be explained in detail and demonstrated by means of a placebo dosage aerosol.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Babyhaler--a new paediatric aerosol device.

Nebulizers have, until recently, been the mainstay of drug delivery by inhalation in babies and young children. The willingness of a young child to cooperate, however, is limited and the 10-12 mins needed to deliver drug using a nebulizer often limits the compliance with this mode of administration in infants. Therefore, drug delivery systems using the metered-dose inhaler (MDI) as the aerosol generator attached to valved holding chambers were developed. The breathing pattern of a baby with lung disease is quite different from that of older children and adults, for whom most large-volume devices were developed. Infants have a high respiratory frequency, small tidal volume, and low inspiratory airflow rate. Therefore, specific conditions for optimal drug use in this particular group of patients have to be met. Efficacy of topical drug delivery depends on the generation of aerosol particles with an adequate size distribution (technical prerequisites), the breathing pattern of the child (physiological requirements), and the willingness of a young child to cooperate with parental drug administration (practicality and compliance). Infants with lung disease have a tidal volume of 8-10ml/kg body weight. The volume of a spacer device must be such that about 5-10 breaths would be needed to provide an adequate dose. In addition, the dimensions of a spacer device must be such that sufficient drug particles of optimal size will be generated to minimize impaction and deposition within the device. The Babyhaler consists of a tubular chamber 230mm long, with a volume of 350ml and low-resistance inspiratory and expiratory valves.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗

Improved airway targeting with the CFC-free HFA-beclomethasone metered-dose inhaler compared with CFC-beclomethasone.

Hydrofluoroalkane-134a (HFA) beclomethasone dipropionate (BDP) was formulated in a metered-dose inhaler (MDI) to deliver a particle size of 1.1 microm compared with 35 microns for currently marketed chlorofluorocarbon (CFC)-BDP products. Two phase I single-dose human deposition studies were conducted using technetium 99m-radiolabelled BDP in a press-and-breathe actuator without an add-on spacer. A healthy volunteer study (n=6) showed that 55-60% of the HFA-BDP ex-actuator dose was deposited in the lungs, with 29-30% deposited in the oropharynx. CFC-BDP deposition was 4-7% in the lungs and 90-94% in the oropharynx. The pattern of deposition within the lung showed that HFA-BDP was spread diffusely throughout the lung airways, whereas CFC-BDP was confined to the central airways with little, if any, peripheral airway deposition. A second study with asthmatics (n=16) confirmed that 56% of the HFA-BDP dose was deposited in the airways, with 33% in the oropharynx. In conclusion, hydrofluoroalkane-134a-beclomethasone dipropionate deposition was much greater in the airways than chlorofluorocarbon-beclomethasone dipropionate, with a concomitant reduction in oropharyngeal deposition. The increased lung deposition efficiency of the hydrofluoroalkane propellant has led to a reduction in the amount of beclomethasone dipropionate needed to achieve a similar efficacy. The penetration of the hydrofluoroalkane to the small airways may provide asthma treatment not afforded by conventional chlorofluorocarbons.

Adolescent↗

Efficacy of chlorofluorocarbon-free beclomethasone dipropionate 400 micrograms day-1 delivered as an extrafine aerosol in adults with moderate asthma.

Beclomethasone dipropionate (BDP) has been reformulated in a chlorofluorocarbon-free propellant, hydrofluoroalkane-134a (HFA), resulting in an extrafine aerosol which gives improved drug delivery to the airways. The objective of this 6 week, placebo-controlled study was to evaluate the clinical efficacy of HFA-BDP 400 micrograms day-1 in 256 adult patients with moderate asthma. This is a lower daily dose than that recommended for existing BDP inhalers in current treatment guidelines for moderate asthma (NIH publication 95-3659). Another objective was to evaluate whether delivering the 400 micrograms dose as four actuations of 50 micrograms twice daily (HFA-BDP 50 micrograms) provided equivalent asthma control to delivering the dose as two actuations of 100 micrograms twice daily (HFA-BDP 100 micrograms) without the use of a spacer or holding chamber. Both active treatments produced a significant change from baseline in morning peak expiratory flow (PEF), which was significantly larger than that in the placebo group (P < or = 0.017) throughout the study. The mean changes from baseline in morning PEF at weeks 5-6 were 47.0 l min-1 in the combined HFA-BDP group and 16.5 l min-1 in the HFA-placebo group. The two dose strengths were statistically equivalent (P = 0.017 for equivalence testing). The active treatments also produced significant improvements compared with placebo in evening PEF, forced expiratory volume in the first second, forced expiratory flow over 25-75% of vital capacity, sleep disturbance scores and daily beta-agonist use. The study medication was well tolerated, with a low incidence of adverse events. The results from this study demonstrate that a daily dose of 400 micrograms HFA-BDP (given in 50 micrograms and 100 micrograms strengths) provides dose proportionality and effective control in patients with moderate asthma.

Administration, Inhalation↗

Comparison of terbutaline via the Nebuhaler and salbutamol via the Volumatic: theory and practice.

The bronchodilating efficacy of terbutaline (250 micrograms.puff) inhaled via the Nebuhaler and salbutamol (100 micrograms.puff) inhaled via the Volumatic has been studied in 30 patients with reversible obstructive airways disease in a randomized crossover study. The salbutamol/Volumatic combination produced significantly greater bronchodilatation than terbutaline/Nebuhaler (one puff, p less than 0.001; eight puffs, p less than 0.01). The findings are discussed with particular reference to the theories of spacer action.

Albuterol↗

Safety of inhaled corticosteroid therapy in young children with asthma.

BACKGROUND: Physicians have had some reluctance to use inhaled corticosteroids in very young children with asthma because of the possible risks of adverse systemic effects. OBJECTIVE: The purpose of this study was to evaluate the effects of fluticasone propionate on growth and adrenocortical function in young children with asthma. METHODS: We performed an open, prospective study for 24 weeks of 20 children with asthma, 2.5 to 5.0 years of age, who had received fluticasone by a large volume spacer at dosages ranging from 190.50 to 565.40 microg/m2 daily. Growth was evaluated by height standard deviation scores measured by a stadiometer. Adrenocortical function was evaluated twice in each child, before and after the study, by determining fasting serum cortisol concentrations at 8 AM and also at 30 and 60 minutes after adrenocorticotropic hormone stimulation. Posttreatment values of height standard deviation scores and fasting morning serum cortisol concentrations were compared with those of 18 age-matched children, who constituted the control group. RESULTS: The evaluation of mean +/- SEM (and range) of height standard deviation scores revealed a significant decrease from 0.44 +/- 0.27 (-1.46 to 2.22) to 0.28 +/- 0.26 (-1.51 to 2.07; P = 0.01) at week 18 and to 0.25 +/- 0.24 (-1.90 to 2.13; P = 0.04) at the week 24 in fluticasone-treated children. At the end of the treatment, however, height standard deviation scores of these children did not differ significantly (P = 0.35) from those of the control group. Delayed growth with medium-duration treatment was not associated with alterations in serum cortisol measurements, either at baseline or after stimulation. The mean fasting morning serum cortisol concentrations did not differ significantly between the fluticasone-treated patients and the control group. CONCLUSIONS: Some concern prevails about the safety of medium- or long-term treatment with regularly inhaled corticosteroids in young children with asthma. The prepubertal growth may be delayed, but the effect on ultimate height remains uncertain in such children. Growth should be regularly monitored in children who begin inhaled corticosteroid therapy for mild persistent asthma at an age <5 years old.

Administration, Inhalation↗

Inhaled salbutamol for wheezy infants: a randomised controlled trial.

BACKGROUND: Salbutamol is frequently used as a bronchodilator for infants who wheeze. Many single dose studies have questioned its effectiveness. AIMS: To investigate the response of wheezy infants to salbutamol over an extended time period in order to elucidate either symptomatic relief or a protective effect. METHODS: Eighty infants under 1 year, with persistent or recurrent wheeze and a personal or family history of atopy, were recruited to a randomised, double blind, cross over, placebo controlled trial. Salbutamol (200 microg three times daily) or placebo were administered regularly over two consecutive treatment periods of four weeks via a spacer and mask. Symptoms of wheeze and cough were recorded in a diary. At the end of the study pulmonary function tests were performed before and after salbutamol (400 microg). RESULTS: Forty eight infants completed the diary study; 40 infants underwent pulmonary function testing. No difference in mean daily symptom score was observed between the salbutamol and placebo periods. There was no difference in the number of symptom free days. Compliance and forced expiratory flows remained unchanged and resistance increased following salbutamol. There was no relation between the response measured by symptom score or pulmonary function in individual patients. CONCLUSION: In wheezy infants with an atopic background, there was no significant beneficial effect of salbutamol on either clinical symptoms or pulmonary function. Clinical effects could not be predicted from pulmonary function tests. Salbutamol cannot be recommended as the bronchodilator of choice in this age group.

Administration, Inhalation↗

Aerosol therapy and the fighting toddler: is administration during sleep an alternative?

Insufficient cooperation during administration of aerosols by pressurized metered dose inhaler (pMDI)/spacers is a problem in nearly 50% of treated children younger than 2 years. For these children, administration during sleep might be more efficient. However, it is unknown how much aerosol reaches the lungs during sleep. The aim of this study was to determine in vitro the lung dose in young children from a pMDI/spacer during sleep and while being awake. Breathing patterns were recorded by a pneumotachograph in 18 children (age 11 +/- 5.1 months) during sleep and wakefulness. Next, breathing patterns were replayed by a computer-controlled breathing simulator to which an anatomically correct nose-throat model of a 9-month-old child was attached. One puff of budesonide (200 microg) was administered to the model via a metal spacer. Aerosol was trapped in a filter placed between model and breathing simulator. The amount of budesonide on the filter (5 lung dose) was analyzed by HPLC. For each of the 36 breathing patterns, lung dose was measured in triplicate. The sleep breathing patterns had significantly lower respiratory rate and peak inspiratory flows, and smaller variability in respiratory rate, tidal volume, and peak inspiratory flows. Lung dose (mean +/- SD) was 6.5 +/- 3.2 and 11.3 +/- 3.9 microg (p = 0.004) for the wake and sleep breathing pattern, respectively. This infant model-study shows that the lung dose of budesonide by pMDI/spacer is significantly higher during sleep compared to inhalation during wake breathing. Administration of aerosols during sleep might, therefore, be an efficient alternative for uncooperative toddlers.

Administration, Inhalation↗

Effect of beclomethasone dipropionate on bone mineral content assessed by X-ray densitometry in asthmatic children: a longitudinal evaluation.

There is little information on bone turnover in asthmatic children taking long-term treatment with inhaled steroids (ICS). The aim of this longitudinal study was to determine the effects of inhaled beclomethasone dipropionate (BDP) on bone mineral density (BMD), in asthmatic children treated over a period of six months. BMD and growth were studied in two age- and sex-matched groups of asthmatic children. These comprised: 14 asthmatic children (Group 1) who had taken BDP in a dosage of 300-400 micrograms daily through a 145 ml spacer device for at least 6 months (mean age 9.1 yrs); and a control group of 16 age- and sex-matched asthmatic patients (Group 2) not treated with ICS (mean age 9.5 yrs). Mean duration of asthma was 5.7 yrs in Group 1 and 5.5 yrs in Group 2. Vertebral BMD (L2-L4) was measured by dual energy X-ray absorptiometry (DEXA) at the beginning (baseline) of the study and 6 months later. There were no significant differences in the baseline bone mass (mean +/- SEM) between the two groups (0.63 +/- 0.03 and 0.64 +/- 0.02 g.cm-2 in Group 1 and 2, respectively). During the observation period, bone density increased, by 4% (95% confidence interval (95% CI) 2-6) in the control group and by 2.3% (95% CI 0.4-4.2) in the group under BDP treatment, showing no significant influence of the treatment. No difference was found in height velocity evaluated before starting BDP and after 6 months of therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗

Bronchodilator delivery in acute airflow obstruction. A meta-analysis.

OBJECTIVE: To compare the effect of bronchodilator delivery by use of a metered-dose inhaler (MDI) or wet nebulizer on objective measurements of acute airflow obstruction in adult patients. METHODS: Published and unpublished research was identified by MEDLINE searches for articles published from 1966 to 1994, review of scientific citations, review of article bibliographies, communication with experts in the area of asthma therapy and aerosol delivery, primary investigators, and a manufacturer of spacer devices. Eighteen studies were selected from 159 potentially relevant articles by independent review in triplicate. Selection criteria included randomized trials that compared bronchodilator delivery by use of an MDI and wet nebulizer in adults with acute exacerbations of asthma or chronic obstructive pulmonary disease who were treated in an emergency department or a hospital. Data for patient characteristics, study setting, bronchodilator doses, outcomes, and methodological quality were independently extracted. RESULTS: Twelve studies with a total of 507 patients had sufficient data to calculate an effect size (in SD units) for improvement in airflow obstruction after bronchodilator delivery. All but 2 studies used spacer devices with the MDI. The overall treatment effect size was -0.02 (95% confidence interval [CI], -0.20 to 0.16) that favored the MDI, but the magnitude of the effect size was not clinically or statistically significant. No significant effect was observed in the subgroup analyses that compared the diagnosis: asthma, -0.17 (CI, -0.41 to 0.07) compared with chronic obstructive pulmonary disease, 0.23 (CI, -0.35 to 0.81); bronchodilator dose; or methodological quality. The results of a sensitivity analysis that included 5 of 6 excluded studies supported the findings from the primary analysis: 0.05 (CI, -0.11 to 0.20). CONCLUSIONS: Bronchodilator delivery by means of an MDI or wet nebulizer is equivalent in the acute treatment of adults with airflow obstruction. Spacer devices were used for bronchodilator delivery with an MDI in most studies and are recommended for the treatment of acute airflow obstruction. The choice of the delivery method will depend on the need for expedient treatment, availability of staff, consideration of costs, and findings from studies designed to evaluate treatment effects from larger than standard doses of bronchodilators delivered by use of an MDI.

Acute Disease↗

Improvement in aerosol delivery with helium-oxygen mixtures during mechanical ventilation.

In mechanically ventilated patients with airway obstruction, helium-oxygen (He-O2) mixtures reduce airway resistance and improve ventilation, but their influence on aerosol delivery is unknown. Accordingly, we determined the effect of various He-O2 mixtures on albuterol delivery from metered-dose inhalers (MDIs) and jet nebulizers in an in vitro model of mechanical ventilation. Albuterol delivery from a MDI was increased when the ventilator circuit contained 80% helium and 20% oxygen (He-O2 80/20) versus O2: 46.7 +/- 3.3 versus 30.2 +/- 1.3 (SE)% of the nominal dose (p < 0.001)-the difference was mainly due to decreased drug deposition in the spacer chamber, mean 39.2% and 55.2%, respectively (p < 0.001). Nebulizer efficiency at a flow rate of 6 L/min was five times lower with He-O2 80/20 than O2, and the amount of nebulized drug was inversely correlated with gas density (r = 0.94, p < 0.0001). When the nebulizer was operated with O2, greater albuterol delivery was achieved when the ventilator circuit contained He-O2 rather than O2. In summary, He-O2 mixtures in the circuit increased aerosol delivery for both MDIs and nebulizers in the mechanically ventilated model by as much as 50%. In conclusion, at appropriate flow rates and concentrations, He-O2 in the ventilator circuit may improve aerosol delivery in mechanically ventilated patients with severe airway obstruction.

Aerosols↗

Effects of high-dose inhaled fluticasone propionate on the hypothalamic-pituitary-adrenal axis in asthmatic patients with severely impaired lung function.

BACKGROUND: The effects of high-dose fluticasone propionate therapy on dynamic cortisol stimulation in severe asthma are unknown. OBJECTIVE: To evaluate the human corticotropin-releasing factor (hCRF)-stimulated plasma cortisol response to fluticasone propionate therapy in severe asthmatic patients with impaired airway caliber (forced expiratory volume in 1 second [FEV1] < 60% of predicted) and in control subjects. METHODS: Ten severe asthmatic patients (mean FEV1, 47% of predicted) and 10 controls (mean FEV1, 104% of predicted) received fluticasone propionate, 2,000 microg/d, via a 750-mL primed spacer for 2 weeks. Plasma cortisol levels before and after hCRF stimulation and overnight 10-hour urinary cortisol excretion corrected for creatinine concentration (OUCC) were measured at baseline after washout and 12 hours after the last dose of fluticasone propionate. RESULTS: Baseline values before fluticasone propionate use were not significantly different in asthmatic patients vs controls for plasma cortisol before and after hCRF stimulation and OUCC. Comparing values at baseline vs after fluticasone propionate use, there was no significant suppression of plasma cortisol levels before (378.2 vs 357.4 nmol/L) or after (510.5 vs 507.9 nmol/L) hCRF stimulation or OUCC (8.2 vs 7.5 nmoL/mmoL) in asthmatic patients. In controls, all outcomes were significantly suppressed comparing values before vs after fluticasone propionate therapy: plasma cortisol levels before (423.5 vs 200.2 nmol/L; P = .002) and after (503.5 vs 291.1 nmol/L; P = .001) hCRF stimulation and OUCC (6.5 vs 2.4 nmol/mmol; P = .002). CONCLUSION: Patients with severe persistent asthma and impaired airway caliber seem to be protected from developing systemic adverse effects with high-dose fluticasone propionate therapy, as evaluated by basal and dynamic measures of hypothalamic-pituitary-adrenal axis activity.

Adult↗