PURPOSE: While performing pulmonary functions tests (PFTs), variable responses to bronchodilators have been anecdotally noted. It has been suggested that up to fifteen percent of patients with a β2-adrenoreceptor haplotype or genotype may have a negative response to inhaled bronchodilators. To date, there has been sparse literature addressing this phenomenon. This study was conducted to evaluate the distribution of bronchodilator response in patients deemed candidates for PFTs.
METHODS: This is a cross-sectional study looking at the response to nebulized albuterol in 6867 consecutive adult patients undergoing PFTs in one teaching hospital from 1992 to 2007. Forced expiratory volume in one second (FEV1) pre- and post-bronchodilator exposure was measured using plethysmographic equipment by SensorMedic (Yorba Linda, CA). The measurements were made 15 minutes after nebulized albuterol (2 puffs via metered dosed inhaler). There were no excluded studies.
RESULTS: Patients showed a variable response to albuterol as measured by FEV1. Twelve hundred and one patients (20%) had a decrease in FEV1 while 4145 patients (75%) had an increase in FEV1 following an albuterol treatment. Five percent had no response to the albuterol. (See figures 1 and 2).
CONCLUSION: Based on the above findings, it was concluded that there is a variable response to nebulized albuterol in adults undergoing PFTs. Conclusions regarding the patients in whom the FEV1 worsened following bronchodilator (20%) were not studied but certainly was considerable in number and warrants future investigation.
CLINICAL IMPLICATIONS: It may be useful to assess a bronchodilator response individually for each patient undergoing PFTs. A newly discovered negative response in a patient already receiving bronchodilator therapy for obstructive lung disease may suggest to the clinician that bronchodilator therapy may not be warranted and, in fact, may be detrimental to the patient.
DISCLOSURE: Tarun Madappa, No Financial Disclosure Information; No Product/Research Disclosure Information