Pulmonary response to a bronchodilator delivered from three inhalation devices

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

Background

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

Hypothesis/Objectives

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

Animals

Ten healthy Foxhounds.

Methods

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

Results

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

Conclusions and Clinical Importance

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

The influence of inhaler selection on efficacy of asthma therapies

Many different devices are available to aid inhalational drug delivery. Although each device is claimed to have advantages over its rivals, the evidence to support greater efficacy of a particular device is scanty. Most comparative studies are underpowered or flawed in their design. They may use inappropriate end-points, or involve healthy subjects, whose response may be very different from the patient with acute severe asthma. The dosage of drug used in a trial may be at the shallow part of the dose-response curve, masking differences in devices. Only in a few cases have clinical trials detected a significant difference between devices, and trials have rarely taken patient preference into account. The most efficacious device in practice is likely to be the one that the patient will use regularly and in accordance with a health care workers' recommendations.

Pressurised metered dose inhalers versus all other hand-held inhaler devices to deliver beta-2 agonist bronchodilators for non-acute asthma

BACKGROUND

A number of different inhaler devices are available to deliver beta2-agonist bronchodilators in asthma. These include hydrofluoroalkane (HFA) or chlorofluorocarbon (CFC)-free propelled pressurised metered dose inhalers (pMDIs) and dry powder devices.

OBJECTIVES

To determine the clinical effectiveness of pMDI compared with any other available handheld inhaler device for the delivery of short-acting beta-2 agonist bronchodilators in non-acute asthma in children and adults.

SEARCH STRATEGY

The Cochrane Collaboration Clinical Trials register was searched for studies as well as separate additional searches carried out on MEDLINE, EMBASE, CINAHL and also on the Current Contents Index as well as the Science Citation Index. In addition, 17 individual online respiratory journals and 12 electronically available clinical trial databases were also searched. The UK pharmaceutical companies who manufacture inhaled asthma medication were contacted in order to obtain details of any published or unpublished studies.

SELECTION CRITERIA

- The full texts of all potentially relevant articles were reviewed independently by two reviewers.

DATA COLLECTION AND ANALYSIS

Fixed and random effect models were used. Dichotomous outcomes were assessed using Odds Ratios or Relative Risks (RR) with 95% Confidence Intervals (95%CI).

MAIN RESULTS

Eighty-four randomised controlled trials were included in this review, but few could be combined to assess a specific outcome for a given delivery device comparison. Only two studies required demonstration of adequate pMDI technique as an entry requirement. There were no difference between a standard CFC containing pMDI and any other device for most outcomes. Regular use of HFA-pMDI containing salbutamol reduced the requirement for short courses of oral corticosteroids (3 trials, 519 patients: RR 0.67; 95% CI 0.49, 0.91); however the total number of exacerbations were unchanged (3 trials, 1271 patients: RR 1.0; 95% CI 0.75, 1.33).

REVIEWER'S CONCLUSIONS

In patients with stable asthma, short-acting beta-2 bronchodilators in standard CFC-pMDI's are as effective as any other devices. The effect of HFA-pMDI on requirement for oral corticosteroid courses to treat acute exacerbations should be confirmed. Effectiveness studies that use an intention-to-treat analysis are required.

Salmeterol administration by metered-dose inhaler alone vs metered-dose inhaler plus valved holding chamber

STUDY OBJECTIVE

To determine whether a spacer device designed as a valved holding chamber with a flow signal increases the efficacy of the long-acting beta(2)-agonist, salmeterol, in patients who use incorrect technique with metered-dose inhaler (MDI) alone.

DESIGN

Double-blind, randomized, placebo-controlled study.

SETTING

University hospital outpatient rooms.

PATIENTS

Twenty adult outpatients with stable persistent asthma, receiving a daily anti-inflammatory drug.

INTERVENTIONS

Patients were randomized to either salmeterol MDI (incorrect use: 1 s after actuating MDI, inhale rapidly) and placebo plus spacer (correct use: inhale slowly as MDI is actuated, continue to inhale slowly and deeply) or placebo MDI (incorrect use) and salmeterol plus spacer (correct use). The following week, patients received the opposite treatment. The dose was two puffs from each device on each treatment day; each puff was separated by 1 min.

MEASUREMENTS AND RESULTS

After baseline peak expiratory flow (PEF), salmeterol was administered and serial PEF determined (0.5, 1, 2, 3, 4, 6, 8, 10, and 12 h). Administration of salmeterol MDI plus spacer resulted in significantly greater increases in PEF from baseline vs MDI at 4 h (44 L/min vs 10 L/min; p < 0.01) and 6 h (49 L/min vs 24 L/min; p < 0.05). Both methods of administration were equally well tolerated.

CONCLUSION

We conclude that patients who have poor timing and rapid inhalation with salmeterol MDI alone will have greater increases in PEF at 4 h and 6 h and no additional side effects if the dose is administered with a valved holding chamber that is used correctly. Further study is needed regarding other errors in MDI technique with salmeterol.

Inhalation therapy in asthma: nebulizer or pressurized metered-dose inhaler with holding chamber? In vivo comparison of lung deposition in children

OBJECTIVE

To compare lung deposition from a nebulizer and a pressurized metered-dose inhaler (pMDI)/holding chamber to determine their efficiency in aerosol delivery to children.

STUDY DESIGN

Children with stable asthma (n = 17) aged 2 to 9 years inhaled in random order radiolabeled salbutamol from a nebulizer and a pMDI through a nonstatic holding chamber. Body and lung deposition of radiolabeled salbutamol was assessed with a gamma camera.

RESULTS

Mean (absolute dose) total lung deposition expressed as a percentage of the nebulized dose was 5.4% (108 microg) in younger children (<4 years) and 11.1% (222 microg) in older children (>4 years). Mean (absolute dose) total lung deposition expressed as a percentage of the metered dose was 5.4% (21.6 microg) in younger and 9.6% (38.4 microg) in older children.

CONCLUSIONS

For the same age groups we have shown equivalent percentages of total lung deposition of radiolabeled salbutamol aerosolized by either a nebulizer or a pMDI/holding chamber. However, the delivery rate per minute and the total dose of salbutamol deposited were significantly higher for the nebulizer.

Efficacy of bronchodilators administered by nebulizers versus spacer devices in infants with acute wheezing

The aim of this study was to compare the response of infants with acute wheezing to treatments with inhaled terbutaline when administered by nebulizer or by metered-dose inhaler and spacer device (MDI-spacer). Thirty-four infants between the ages of 1 and 24 months who were seen in our emergency department for acute wheezing were studied in a double-blind, randomized trial. The participants received two treatments of terbutaline at 20-min intervals, either by a nebulizer (2 mg/dose in 2.8 mL of 0.9% saline solution) or by an MDI-spacer device (0.5 mg/dose). The outcome measure was a clinical score, based on respiratory rate, degree of wheezing, retractions, degree of cyanosis, color, and pulse oximetry data measured before treatment, 20 min after the first treatment, and again 20 min after the second treatment. There was no difference in the rate of improvement in the clinical score between infants who received terbutaline by nebulizer and those who received it by MDI-spacer. We conclude that MDI-spacers and nebulizers are equally effective means of delivering beta-2 agonists to infants and small children with acute wheezing.

Adrenal suppression among asthmatic children receiving chronic therapy with inhaled corticosteroid with and without spacer device

BACKGROUND

Inhaled corticosteroids have become a first-line treatment for chronic asthma. It has been shown that inhaled corticosteroids can have a measurable effect on the hypothalamic-pituitary-adrenal axis in asthmatic children.

OBJECTIVE

To investigate the prevalence of adrenal suppression among asthmatic children receiving chronic therapy with low to moderate doses (up to 1000 micrograms) of inhaled beclomethasone dipropionate via a metered dose inhaler (MDI) and via MDI attached to a spacer device (MDI-spacer).

METHODS

The study included 39 asthmatic children currently undergoing therapy; 24 received beclomethasone dipropionate by MDI attached to a spacer, and 15 directly by MDI. All the patients had been treated for at least 4 months. Another 21 children were normal controls. The 24-hour urinary free cortisol excretion was measured to evaluate hypothalamic-pituitary-adrenal axis function.

RESULTS

Seven of 15 (47%) patients from the MDI group had reduced 24 hour-urinary free cortisol excretion and 2 of 24 (8%) in the MDI-spacer group (P = .006). The mean 24-hour urinary free cortisol excretion of the MDI group was 0.0185 +/- 0.0089 microgram/gram creatinine, and the MDI-spacer and the control groups were, 0.0290 +/- 0.0138 microgram/gram creatinine and 0.0270 +/- 0.0118 microgram/gram creatinine, respectively, (P = 0.37, f = 3.51 ANOVA).

CONCLUSION

Chronic inhalation of low to moderate doses of corticosteroids is associated with adrenal suppression in some asthmatic children. This side effect is more common among patients inhaling directly from the MDI and is less frequent when a large volume spacer is attached to the MDI.

Relative bioavailability of salbutamol to the lung following inhalation using metered dose inhalation methods and spacer devices

BACKGROUND

Inhalation aids do not require coordination between actuation of a metered dose inhaler (MDI) with inspiration and reduce oropharyngeal impaction. The delivery of salbutamol to the lung and systemic availability following inhalation with three commonly used spacers and an open mouth technique have been evaluated using a simple noninvasive technique based on urinary excretion 30 minutes and 24 hours after the dose.

METHODS

Ten healthy subjects inhaled, on randomised study days, 4 x 100 micrograms from a Ventolin MDI and, subsequently, with the aid of a Volumatic, Bricanyl Spacer, and Nebuhaler spacer device. In addition, an open mouth inhaler technique was evaluated. Urine samples were collected 0-30 minutes and 0.5-24 hours after inhalation. From these samples the relative bioavailability to the lung (urinary salbutamol excretion 30 minutes after dosing) and the systemic bioavailability of the dose (24 hour urinary excretion of salbutamol and its metabolite) for each inhalation method was obtained.

RESULTS

The mean (SD) urinary excretion of salbutamol 30 minutes after inhalation using the MDI alone and with the Volumatic, Bricanyl Spacer, Nebuhaler, and open mouth technique was 2.83 (0.78)%, 3.37 (0.69)%, 4.09 (0.91)%, 4.34 (1.60)%, and 3.49 (0.98)%, respectively, expressed as a percentage of the nominal dose. The nebuhaler and Bricanyl Spacer spacer devices were found to increase the relative bioavailability of salbutamol to the lung compared with the MDI alone. Compared with the MDI the inhalation aid increases were much greater than the intra-individual variability of the urinary excretion method. In 11 individuals who each repeated the same inhalation procedure on four separate occasions, the mean (SD) coefficient of variation was 8.24 (2.36)%. The mean (SD) 24 hour urinary excretion of salbutamol and its metabolites was 26.6 (6.79), 27.0 (7.95), and 55.6 (9.74)% of the salbutamol dose for the Volumatic, Nebuhaler, and MDI, respectively. Similar values following the open mouth method and Bricanyl Spacer were 48.9 (10.97)% and 43.8 (11.57)%. These values, representing the systemic availability of the inhaled dose, were lower when inhaling with the aid of the Volumatic and Nebuhaler than inhalation from the MDI alone.

CONCLUSIONS

Spacer devices improve pulmonary bioavailability of salbutamol and reduce the systemically available dose.

Efficacy of albuterol administered by nebulizer versus spacer device in children with acute asthma

The aim of this study was to compare the response to inhaled albuterol after administration by nebulizer with the response after administration by a metered-dose inhaler and spacer device (MDI-spacer) to children with acute asthma. In a double-blind fashion, 33 children (6 to 14 years of age) with forced expiratory volume in 1 second (FEV1) between 20% and 70% of predicted values, and who were seen in the emergency department with acute asthma, were studied. They were treated with aerosolized albuterol or placebo by MDI-spacer, followed immediately by albuterol or placebo administered by nebulizer with oxygen. The dose ratio for albuterol by MDI-spacer versus nebulizer was 1:5. Outcome measures included a clinical score, respiratory rate, arterial oxygen saturation, and FEV1, measured before and 10, 20, and 40 minutes after treatment. With the exception of heart rate (which increased in the nebulizer group and decreased in the MDI-spacer group (p < 0.05), no difference in the rate of improvement of clinical score, respiratory rate, arterial oxygen saturation, or FEV1 was noted during the 40-minute study period between children who received albuterol by nebulizer and those who received it by MDI-spacer. We conclude that spacers and nebulizers are equally effective means of delivering beta 2-agonists to children with acute asthma.

Optimizing drug delivery from metered-dose inhalers

Metered-dose inhalers (MDIs) are being used with increasing frequency to administer medication used in the treatment of respiratory tract disorders. Inhaled medication is delivered directly to the tracheobronchial tree, allowing for a rapid and predictable onset of action. Studies show that only about ten percent of the dose from an MDI actually reaches the lung. The site of deposition within the lung is influenced by the aerosol characteristics, interpatient variability, and the technique by which the patient uses the inhaler. Spacer devices have been designed to overcome some of the problems encountered with MDIs and may be beneficial in certain groups of patients. The studies reviewed in this article suggest ways to alter the variables affecting inhalation in order to optimize drug delivery so that the patient will obtain the most benefit from the inhaled medication.

Reliable salbutamol administration in 6- to 36-month-old children by means of a metered dose inhaler and Aerochamber with mask

A double-blind study was performed to demonstrate that bronchodilator can be administered reliably to infants and children under 3 years of age from a metered-dose inhaler (MDI) by means of an economical valved aerosol-holding chamber device (Aerochamber) fitted with a mask. Symptoms of cough and breathlessness were compared for two 1-week crossover periods with the child either taking active drug or placebo. The MDI and Aerochamber with mask is an effective delivery system for respiratory therapy in these young children.

Asthma: current therapeutic approach

This article discusses the goals of asthma therapy, treatment of the acute exacerbation, and day-to-day management. The importance of early pharmacologic intervention is emphasized. In 1988, the need to hospitalize a child with asthma often represents failure of ambulatory management.

Bronchodilator effect of fenoterol and ipratropium bromide in infants with acute wheezing: use of MDI with a spacer device

Twenty-eight infants admitted to Exequiel González Cortes Children's Hospital because of acute wheezing (AW) were randomly assigned to three study groups. Fenoterol (FNT), ipratropium bromide (IB), and placebo were administered respectively to children in the different groups by means of metered dose inhalers (MDI) with spacers, using doses of 3 puffs every hour, for 4 hours. The degree of bronchial obstruction was assessed clinically and scored with the single-blind method every hour prior to each treatment. The criterion of a bronchodilator effect was a significant decrease in the degree of bronchial obstruction at subsequent scorings. The scores of the three groups were compared using the Student's t test for matched samples. The same test was also applied to the independent samples for determining the superiority of one treatment, FNT or IB, over the other. The results indicated a significant decrease in the scores of the groups receiving FNT and IB (P less than 0.05); this did not occur in the group in which placebo was used. FNT produced a more rapid and sustained effect than IB (P less than 0.05). Significant bronchodilator effect was obtained in infants with AW when repeated doses of FNT or IB were administered with MDI and spacers. This effect was significantly greater in the group treated with FNT.

Asthma in infants and children--treatment of childhood asthma: Part II

The various features of bronchial asthma as it pertains to infants and children are reviewed. Childhood asthma ranks among the most common causes of ill health and creates a myriad of physical and emotional problems for the child. Rarely, it may lead to death. Various anatomic and physiologic differences in children account for the increased risk to symptomatic airway obstruction and poor response to bronchodilators. Other features of childhood asthma that differ from adult asthma including the prognosis, differential diagnosis, and complications are discussed. The authors' views of the general principles, specific therapy, pharmacologic measures, and a self-management intervention program for the management of the pediatric patient with asthma are presented.

Spacer devices used with metered-dose inhalers. Breakthrough or gimmick?

In an effort to improve the delivery of a drug to the lungs, to correct problems of hand-lung discoordination, and to reduce local side effects such as oral candidiasis, a number of spacer devices have been developed to attach to metered-dose inhalers. Administration of bronchodilator drugs to patients with faulty techniques of inhalation has been improved with the addition of spacers. In adults and older children with a correct technique of inhaling bronchodilators, the spacer devices do not seem to have any advantage over the simple metered-dose inhalers. Young children (two to five years) can benefit from inhaled bronchodilators or corticosteroids by use of spacer devices with one-way valves. Older children and especially adults who suffer from dysphonia or thrush from inhaled corticosteroids can also benefit from spacers. In patients whose condition is well controlled with the usual inhaled doses of corticosteroids with no local side effects, spacer devices show promise, but more studies are needed.