MUCOCILIARY CLEARANCE IN PATIENTS WITH CYSTIC-FIBROSIS AND IN NORMAL SUBJECTS

The aim of this study was to examine baseline mucociliary clearance (M CC) in patients with cystic fibrosis (n = 30; mean +/- SEM age, 23 +/- 1 yr; FEV(1), 68 +/- 5% pred; range, 14 to 126%) and a group of norma l subjects (n = 12; mean age, 27 +/- 1 yr) after an aerosol deposition of Tc-99m-sulphur colloid (mass median diameter, 4.8 mu m; geometric standard deviation, 1.6). Dynamic geometric mean images were formed fr om gamma camera data, and the percent clearance of activity after 60 m in (%C-60) was calculated for the whole right lung. Initial deposition of the aerosol was determined in terms of the penetration index, the ratio of peripheral to central activity. For normal subjects, an incre ase in mean inspiratory flow rate (MIFR) (49 +/- 5 versus 21 +/- 3 L/m in, p < 0.05) resulted in an increase in whole right lung MCC (%C-60, 31 +/- 4 versus 18 +/- 2%; p < 0.05). When aerosol delivery was contro lled (MIFR, 34 +/- 5 versus 36 +/- 5 L/min), there was excellent repro ducibility between studies (whole lung %C-60, 34 +/- 8 versus 31 +/- 7 ; NS). The measurement of MCC was highly reproducible in six patients studied on four occasions with a mean coefficient of variation of 3.3 +/- 1%. A breathing pattern to accentuate central deposition was utili zed in the patient studies (MIFR, 49 +/- 4 L/min). Mean MCC was signif icantly reduced in the patient group compared with that in the normal group for the whole right lung (%C-60, 13 +/- 2% versus 28 +/- 4%; p < 0.05) and for the central zone (14 +/- 3% versus 35 +/- 5%; p < 0.05) . There was a significant relationship between whole lung MCC and lung function (RV/TLC% versus %C-60, r = -0.39; p < 0.05) and NIH score (r = 0.39; p < 0.05). There was a trend for enhanced clearance in male p atients independent of lung function, but this was not significant. No difference was found in clearance between patients homozygous or hete rozygous for the Delta F508 mutation. In a subgroup of five patients w ith normal small airways function only two exhibited MCC in the normal range. In patients with cystic fibrosis, MCC was severely impaired, e ven in some with preserved lung function. These results suggest the ne ed for early aggressive treatment in cystic fibrosis.