Bronchodilaters and Lung Funtion Testing

Dear Ask The Doctor: I recently had blood gas test done at a hospital for my breathing difficulties and the doctor told me the results were normal, my question is I had used my nebulizer ( Duoneb solution ) approximately 1 1/2 to 2 hours prior to taking the test, the test involved taking blood from a artery, brisk walking up and down the hall with a monitor on my finger and then doing breathing functions by blowing into a machine which created a chart, would one get a true results using the nebulizer prior to testing or would the test be invalid? Note I informed the technicians about the nebulizer use before the testing began.

Dear Lloyd: Duoneb solution is a nebulised preparation of two drugs Albuterol sulfate and Ipratropium Bromide. Both of these drugs work by dilation of the bronchi, each with a different mode of action. Studies suggest that the combination of the two drugs together via nebuliser is superior to either of the two drugs independently. Peak dosage effect was after one hour and the duration of action lasted greater than 4 hours. The results of your arterial blood gas may be different if no drug was administered and if concerned you could reschedule a blood gas examination without the aid of a broncodilator.