Chest
Volume 95, Issue 4, April 1989, Pages 822-830
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Clinical Investigations
Homogeneity of Bronchopulmonary Distribution of 99mTc Aerosol in Normal Subjects and in Cystic Fibrosis Patients

https://doi.org/10.1378/chest.95.4.822Get rights and content

We characterized the bronchopulmonary distribution of a 0.9 percent saline aerosol (1.12 µM) labelled with 99mTc sulfur colloid in nine normal subjects and five patients with CF. Homogeneity of distribution was quantified using indices derived from computerized analysis of Anger camera pulmonary images including skew (a measure of distribution asymmetry) and kurtosis (a measure of distribution range). Aerosol clearance in 97 minutes (a measure of large, central airway deposition) was also assessed. Values of skew and kurtosis were reproducible for the patients with CF and were significantly elevated compared to the normal subjects. Reproducibility of skew and kurtosis were not studied in the normal subjects. Clearance was not significantly different in the two groups. We conclude that the bronchopulmonary distribution of this radioaerosol is nonuniform in patients with CF, compared to normal subjects, and clearance may be impaired in patients with CF who are severely ill.

Section snippets

Protocol

Nine healthy male volunteers, ranging in age from 22 to 29 years, and five patients (four men and one woman) with CF, ranging in age from 18 to 39 years, were studied (Table 1). All subjects were nonsmokers. All patients with CF were followed regularly in the Cystic Fibrosis Clinic, were in clinically stable condition, and were receiving pancreatic enzyme and multivitamin supplements. Patient 2 was also receiving nebulized antibiotic treatment (gentamicin). Patient 3 was also being treated with

RESULTS

Table 1 shows the results of pulmonary function tests for the nine normal volunteers and five patients with CF. The patients with CF were significantly shorter than the normal volunteers, with a mean (±SD) of 66±2 and 70±3 inches, respectively (p = 0.04; unpaired t-test). Baseline FEV1 and FVC (percent predicted) were significantly lower in the patients with CF, with 35 ±13 percent and 55 ±16 percent, respectively, compared to 89 ±11 percent and 95 ±12 percent, respectively, for the normal

DISCUSSION

We compared homogeneity of aerosol distribution in nine normal volunteers and five patients with CF during a clinically stable phase of the disease. Since it is well known that particle size, inspiratory flow rate, pulmonary volume, and residence time are major determinants of regional aerosol deposition in human airways, care was taken to regulate these factors. The radioaerosol consisted of small droplets (MMAD= 1.12µm). Inspiratory flow rate was controlled at 0.5 L/s. Pulmonary volume at the

ACKNOWLEDGMENTS

We thank Ms. Karen Nelson for preparing the manuscript and Mr. Gerard McCormick for technical assistance.

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