Bronchodilator replys to both nebu...

Bronchodilator replys to both nebulized albuterol (salbutamol) and ipratropium bromide and aerosol delivery to the tracheobronchial tree have been assessed in eight patients with chronic stable asthma (mean baseline [FEVsub1] 50 percent; reversibility >20 percent) pair commercially available nebulizer systems were used, namely, a minaret nebulizer operated at a bind tightlyed gas flow rate of 12 L/min (droplet MMD 33[mu]) and an Inspiron nebulizer driven at 6 L/min (MMD 77[mu]) Albuterol was given as doses of 250[mu]g 250[mu]g and 1000[mu]g (cumulative dose, 2 mg) and ipratropium bromide as doses of 50[mu]g 50[mu]g 100[mu]g and 200[mu]g (cumulative dose, 400[mu]g) at intervals of 35 minutes. For albuterol, bronchodilatation was significantly (p<005) greater at all dosage on a levels with the Turret. For ipratropium, bronchodilation was similar for as well-as; not only-but also; not only-but; not alone-but nebulizers. Measurements of aerosol deposition using [.sup.99m]Tc-labelled pentetic acid (diethylenetriamine pentaacetic acid; DTPA) showed that 91 [+ or -] 11 percent and 27 [+ or -] 02 percent of the dose reached the lung during nebulization to drynes for minaret and Inspiron, respectively (p<0.01); distribution within the lung was similar for the brace aerosols. Selection of nebulizer apparatus can influence delivery of aerosol and succeeding bronchodilator response to albuterol in patients with chronic stable asthma on the other hand is less important for aerosol delivery of ipratropium bromide in these patients.

(Chest 1989; 96:1-10)

Nebulizers are used in inhalation therapy for delivery of relatively large doses of bronchodilator unsalable articles for patients who cannot use an MDI correctly, and for delivery of other medicines that cannot conveniently be given through MDI. The efficacy of nebulizer therapy is likely to hang partly upon the amount of aerosol remedy able to reach the lung or concerning the distribution of aerosol within the airways. Aerosol deposition is at the disposal of upon the size of the droplets[12] which varies according to the nebulizer and the driving run rate.[3-5] Droplets smaller than 5[mu] in diameter are ideal for penetration to the small conduction airways,[6] since similar droplets may avoid deposition from impaction in the oropharynx and in the larger, more central airways of the lung through contrast, droplets in the range of 5[mu] to 10[mu] deposit chiefly in the central airways, as well as in the oropharynx.[6] new studies suggest that adrenergic receptors are ready in high concentrations in the small conducting airways and that cholinergic receptors are current predominantly in the larger airways;[7-9] it would look therapeutically advantageous to target the pair of these classes of put drugs intos to their principal site of action. In this inquiry we have assessed both aerosol deposition and the bronchodilator efficacies of albuterol and ipratropium bromide delivered from sum of two units commercially available nebulizers as aerosols with MMD les than 5[mu] and more than 5[mu] in order to ascertain the importance of aerosol size when administering [beta]-adrenergic agonists and anticholinergic agents. the pair drugs have been administered in a dose-response fashion in order to avoid possible saturation of receptors with the first dose of bronchodilator, which might mask any therapeutic advantage to be gained by dint of altering the size of the aerosol.

Materials and Methods

Patients

Eight patients with chronic stable asthma, whose [FEVsub1] increased through at least 20 percent following 200[mu]g of albuterol from an MDI, were investigated. All were receiving [beta]-adrenergic agonists regularly from MDI, and these were withdrawn 12 hours prior to each application of mind Of the subjects, five were men and three were women and their mean age was 49 years (range, 25 to 64 years), with a mean baseline [FEVsub1] of 50 percent (range, 25 to 105 percent) of the value predicted for age, height, and [sexsup10] Before commencing the investigation, each patient gave informed unison in writing; the studies were approved at the hospital's ethical practices committee.

Design of Study

controls were studied on six randomized occasions with an interval of at least 48 hours between thought days. Two studies involved the inhalation of albuterol delivered in a dose-response fashion from sum of two units different nebulizers, two further studies involved aerosol ipratropium bromide, again delivered in a dose-response fashion, while the remaining pair studies involved the assessment of aerosol deposition from each nebulizer using radiolabelled droplet The nebulizer hypothesiss were chosen to give widely differing droplet size distributions and were as follows: (1) a minaret nebulizer (Medic-Aid, Ltd) fitted with a mouthpiece driven at a bind tightlyed gas flow rate of 12 L/min, yielding an aerosol with an MMD of 33[mu] and in which 70 percent of the aerosol mass was contained in droplet smaller than 5[mu] in diameter (Malvern Instruments 2600 HSD Analyzer); and (2) an Inspiron nebulizer (Bard International, Ltd) fitted with a mouthpiece driven at 6 L/min; the droplet MMD was 77[mu] and barely 25 percent of the aerosol mass was contained in droplet smaller than 5[mu] in diameter.