Comparison of Airway Clearance Efficacy of Sine Wave and Triangular Wave High Frequency Chest Wall Oscillation (HFCWO) Devices in Patients With Cystic Fibrosis

Participation in the study will be for 4 days. During initial subject recruitment, investigators will review inclusion and exclusion criteria with potential subjects. Upon enrollment, qualifying subjects will be asked to perform their last BD of the day at 8 PM on the day, but will be allowed to continue with the rest of their routine therapeutic regimen (including aerosols). They will be instructed to come on day 1 of the study at 8 AM. During this visit, they will complete a brief questionnaire and undergo an abbreviated physical exam, concentrating on chest findings. The questionnaire and exam will be used to confirm all subjects meet the study inclusion and exclusion criteria. The current therapeutic regimen being followed on day one of the study will be reviewed and the patient will be asked not to make any changes during the study period. Subjects will then perform pulse oximetry, spirometry, and lung volumes via body plethysmography. A sputum specimen will be collected for rheologic studies in a special container.

Once this is completed, the patient will perform a 30 minute BD session according to the first treatment of the randomly allocated sequence. The vest, or jacket, worn by the subject differs for the sine wave and triangular wave devices. Subjects will be blinded as to the type of system used at each session. Blinding will be accomplished by the patient wearing eye blinds of the type used commercially for assisting sleep. Investigators will assist the patient with putting on the HFCWO device. A large, lightweight poncho will then be placed over the patients head, thereby concealing the vest and attached equipment. The blinds will then be removed and the patient will subsequently put on a set of ear protectors used commercially for workers with noise exposure. This will prevent the patients from recognizing the difference in the sounds produced by the two devices. Only the respiratory therapist supervising the session will know of the treatment assignment. It is possible the subjects will be able to differentiate the two devices despite these measures to blind treatment. Subjects will use the vest devices provided by the investigators rather than bringing their vest devices from home. Prior to initiating the study, both devices will be tested, and adjusted as necessary, to ensure "dialed in" pressures and frequencies are accurately delivered.

During this session all the sputum produced will be collected in pre-weighed special containers and sealed for immediate processing. Patients will use their routine combination of aerosols in conjunction with the BD session. At the end of the 30 minute session the patient will be asked to produce a second sputum specimen which will be collected for rheologic studies in a special container.

After this is completed, pulmonary function measurements will be repeated. The patient will then undergo an abbreviated physical exam and complete a brief questionnaire (included in this application). The 8-item survey instrument focuses on adverse effects and comfort associated with use of the HFCWO device, primarily using a 5-point scale. Responses to the experience of using each device will be compared using standard statistical methodology.

The patient will be discharged after the measurements are completed and will be asked to return 3 days later for the second treatment in the allocated sequence. The patient will be asked to continue in the interim with their daily routines, trying not to make major changes in physical activity, environmental exposures or fluid intake. For the second treatment, the patient will be instructed again to perform BD at 8 PM on the evening before the return appointment.