EFFECTS OF COMBINED TREATMENT WITH RHDNASE AND AIR-FLOW OSCILLATIONS ON SPINNABILITY OF CYSTIC-FIBROSIS SPUTUM IN-VITRO

Treatment with either rhDNase or high-frequency oscillation has been s hown to be effective in improving the physical and transport propertie s of airway secretions in cystic fibrosis (CF). The objects of this in vitro study was to examine whether combined treatment with oscillatio n and rhDNase results in greater change of CF sputum spinnability than either treatment by itself. Aliquots of sputum (0.4 g) from eight CF patients were subjected to the following protocols for 15 minutes and then followed for a total of 30 minutes: 1) incubation with 0.04 mi DN ase 50 mu g rhDNase/normal saline (10% dilution) at 37 degrees C to ac hieve 5 mu g DNase/g of sputum final concentration; 2) airflow oscilla tion at 27 Hz similar to the airflow magnitude produced by a commercia l high-frequency chest compression (HFCC) device; 3) negative control with no treatment; 4) positive (dilution) control, incubating with 10% saline by volume; 5) combination of DNase and oscillation, and 6) com bination of saline and oscillation. For each protocol, sputum spinnabi lity (in mm, mean +/- SD) was measured by means of a filancemeter at b aseline, 15, and 30 minutes. Treatment with DNase decreased spinnabili ty significantly more than either saline or oscillation at 15 and 30 m inutes (P < 0.02 and P < 0.04, respectively). Incubation with saline o r oscillation of CF sputum for 15 and 30 minutes decreased spinnabilit y significantly compared with control. The combination of DNase and os cillation decreased spinnability significantly more than treatment wit h DNase alone (3.74 +/- 0.45 vs. 6.54 +/- 0.73 at 15 minutes, P < 0.01 ). The combination of saline and oscillation over 15 minutes decreased spinnability similarly to the application of DNase alone over the sam e period of time (7.84 +/- 1.91 vs. 6.54 a 0.73, respectively). These in vitro results demonstrate an optimal effect on sputum spinnability when DNase and oscillation are used concomitantly. This suggests that combining biochemical (rhDNase) and physical (HFCC) treatments in CF p atients may provide greater benefits than treatment with one modality at a time. (C) 1995 Wiley-Liss, Inc.