Chest
The Acute Effect of Ipratropium Bromide Bronchodilator Therapy on Cough Clearance in COPD
Section snippets
METHODS
Fifteen patients (nine men and six women), ranging in age from 49 to 78 years (mean, 63 years), were studied. Table 1 provides data on each subject's age, pulmonary function, smoking history, and medications. Patients had relatively stable moderate-to-severe air-way obstruction with an FEV1/FVC ratio of <0.70 (mean = 0.46). Subjects had a smoking history of at least 10 pack-years (subjects were instructed to refrain from smoking on the days of the study) and were free of respiratory infections
RESULTS
Figure 2 is a plot of retention versus time for one of the subjects who met the criterion for sufficient particle retention at 60 min. In this patient, the clearance of particles from the lung was similar through 60 min for all three study days but during the cough period (60 to 120 min) the rate of clearance was much greater for the placebo + cough versus IB + cough day. Three of the 15 patients did not meet the criterion of R60 ≥0.50 for all three study days (subjects 4, 6, and 12). An
DISCUSSION
We chose IB to test the effect of bronchodilation on cough clearance because others had shown that similar doses of the drug had caused no change in baseline mucociliary clearance in normal, asthmatic, or chronic bronchitis subjects.6, 7, 8 Consequently, we decided that it was not necessary to repeat these studies by adding an additional two study days to determine IB and placebo effects on mucociliary clearance. Consistent with these previous studies, we found no difference in IB versus
CONCLUSION
We have found that the effectiveness of voluntary cough for clearing mucus from the airways is diminished following IB therapy. Cough clearance of radiolabeled particles deposited in the airways was faster following placebo than IB therapy despite a tendency for higher peak flow rates for coughing following the bronchodilator. It is not clear whether this inhibition of cough clearance is due to (1) flow and airway mechanics effects induced by bronchodilation or (2) an effect on the rheology of
REFERENCES (27)
- et al.
Fluid mechanical experiments relevant to coughing
J Biomech
(1978) - et al.
Ipratropium bromide: mucociliary clearance rate and airway resistance in normal subjects
Br J Dis Chest
(1977) - et al.
Aerosol therapy with Sch 1000: short-term mucociliary clearance in normal and bronchitic subjects and toxicology in normal subjects
Chest
(1978) - et al.
Production of Tc99m-labeled iron oxide aerosols for human lung deposition and clearance studies
Int J Appl Rad Isotopes
(1980) Effect of ipratropium bromide on airway mucociliary function
Am J Med
(1986)Double-blind study of ipratropium bromide, a new anticholinergic bronchodilator
J Allergy Clin Immunol
(1977)- et al.
Effects of postural drainage, exercise, and cough on mucus clearance in chronic bronchitis
Am Rev Respir Dis
(1979) Clinical aspects of mucociliary transport
Am Rev Respir Dis
(1977)- et al.
Bronchodilators increase airway instability in cystic fibrosis
Am Rev Respir Dis
(1985) Ipratropium bromide
N Engl J Med
(1988)
Acute effect of ipratropium bromide at therapeutic dose on mucus transport of adult asthmatics
Eur J Respir Dis
Cough enhanced mucus clearance in the normal lung
J Appl Physiol
An improved spinning top homogeneous spray apparatus
J Appl Physiol
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Supported by contract from Boehringer Ingelheim Pharmaceuticals, Inc, NHLBI FIRST Award HL39411, and US EPA Cooperative Agreement CR812738.
This study was performed in laboratories of the US Environmental Protection Agency; thus, this manuscript has been reviewed by the Health Effects Research Laboratory, US EPA, and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.
Manuscript received April 14; revision accepted June 30.