Bronchodilator effects of ipratropium bromide and albuterol sulfate among subjects with tetraplegia

Abstract

Objective: In addition to lung volume restriction, persons with chronic tetraplegia demonstrate obstructive airway physiology evinced by pharmacologically-induced bronchodilation. We previously found independent evidence that anticholinergic agents (ipratropium bromide; IB) and beta-2 adrenergic agonists (albuterol sulfate; AS) were associated with significant bronchodilation in subjects with tetraplegia as determined via spirometry or body plethysmography. Direct comparison of these two classes of agents has received little attention.

Methods: Twelve subjects with chronic tetraplegia completed single dose treatment on alternate days with nebulized IB or AS. Patients underwent pre- and 30-minute post-bronchodilator spirometry, body plethysmography, and impulse oscillation system (IOS) in accordance with established protocols.

Results: Spirometry and specific airway conductance revealed significant bronchodilator responsiveness following both IB and AS. As determined by increases in specific airway conductance post-bronchodilator, IB tended toward greater bronchodilation than AS (71% vs. 47%). IOS revealed a greater reduction in central airway resistance (R20) following IB compared to AS (22% vs. 9%, P < 0.01). A greater number of subjects exhibited a clinically significant reduction in R20 following IB compared to AS (58% vs. 8%, P < 0.01).

Conclusion: Among subjects with tetraplegia, both IB and AS elicit significant bronchodilation, although the magnitude of the bronchodilator response is greater following IB. This lends support to theory of overriding cholinergic airway tone in tetraplegia. The IOS findings further suggest that the predominant site of action of IB is upon the larger central airways congruent with findings in able-bodied subjects.

Keywords:

• Spinal cord injury
• Tetraplegia
• Pulmonary function
• Bronchodilator

Acknowledgments

This research was supported by the Department of Veterans Affairs Rehabilitation Research and Development Service (#B9212-C, #B4162-C) and the James J. Peters VA Medical Center. The research performed in this manuscript was completed at the James J. Peter VA Medical Center (JJPVAMC) and approved by the JJPVAMC Institutional Review Board. All authors listed on this study had no conflict of interest.

Author declaration

On behalf of all authors, we agree to the rules, regulations and requirements of the publication process. All authors had significant contributions to the study design, performance, data analysis/interpretation, manuscript development and approval of the final document.

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