Date of Award

1998

Degree Type

Thesis

Degree Name

Bachelor of Science Honours

Faculty

Faculty of Communications, Health and Science

First Advisor

Alan Morton

Second Advisor

Dr Paul Sacco

Abstract

Salbutamol is a Beta-2-agonist, commonly prescribed for the prevention and reversal of Exercise induced asthma (EIA). The purpose of this study was to compare the efficacy of a spacer device in the delivery of salbutamol for the prevention of EIA Thirteen confirmed asthmatic subjects (10 female and 3 male), completed 3 exercise test sessions consisting of three treatments a) Ventolin via MDI (metered dose inhaler) and placebo via spacer, b) Ventolin via spacer and placebo via MDI and c) Placebo via spacer and MDI, randomly administered utilising a single blind, cross--over design. Following treatment, subjects completed an asthmogenic physical challenge (8-minute, graded treadmill run at 75-85% predicted heart rate maximum). The lung function variables FEV, FVC, PEFR, FEF­­50, and FEF25-75 were recorded pre-treatment, pre exercise and 0, 3, 5, 7, 10, 20 and 30 minutes post-exercise. Of the 13 subjects, only 7 demonstrated sufficient decrement in FEV1 to be classified as ElA. In the subjects who demonstrated EIA, no significant differences were found for post-exercise lung function measures between the spacer and MDI mean scores. Administration of salbutamol via the spacer resulted in significant improvements over the- placebo scores in MEF50 and FEF25-75 and significant test/time interactions for FVC and FEV1, however the MDI scores were not significantly different to the placebo. The findings were congruent with previous findings which suggest that spacer delivery offers no significant advantage m preventing EIA in subjects who are skilled m MDI administration techniques. The inability to induce EIA in 6 of the 13 subjects may relate to the high lability scores recorded for several subjects suggesting that bronchoconstriction was evident prior to testing. This may have been due to the high pollen count recorded during testing. Secondly, the asthmogenic nature of the testing environment may have been hindered due to the high level of fluctuation in the relative humidity recorded for each test. Although conclusions have been made concerning spacer efficacy, this study should be replicated under more asthmogenic conditions to confirm the findings of this study.

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