Comparison of Airway Clearance Therapy in Cystic Fibrosis Using the Same VEST Therapy Device But With Different Settings

University of Minnesota (UMN)

Status and phase: Completed; Phase 4

Conditions: Cystic Fibrosis

Treatments: Device: HFCWC with lower pressure/mid-frequency settings; Device: HFCWC with higher pressure/variable-frequency settings

Study type: Interventional

Funder types: Other; Industry

Identifiers

NCT00685035

0802M26441

Details and patient eligibility

About

Our primary hypothesis is that airway clearance therapy with sine waveform HFCWO using higher inflation pressures combined with both low and high oscillator frequencies will result in greater sputum production compared to sine waveform HFCWO with lower inflation pressures and mid-frequency oscillations.

Full description

Patients with cystic fibrosis (CF) perform daily airway clearance therapy to facilitate removal of secretions from their airways. Many different techniques are available to achieve this and there is currently no consensus as to which form of therapy is most effective. High frequency chest wall oscillation (HFCWO) is used by CF patients throughout the United States and abroad. To perform this therapy, the patient wears a vest which fits over the entire torso and is connected to an air compressor. The compressor generates oscillating air pulses that are transmitted to the lungs, thereby mobilizing secretions. The most commonly used device is The Vest™ Airway Clearance System, (Hill-Rom Inc, St Paul, MN). Adjustment of the inflation pressure and frequency of oscillations affects the volume of displaced air and flow of air measured at the mouth of the patient. Previous studies indicate this form of therapy is as effective as more traditional and cumbersome forms of therapy. However, it is unclear which inflation pressures and oscillator frequencies provide optimal airway clearance. Some studies of sine waveform HFCWO reported the largest volume of air displacement and highest air flow measured at the mouth when using a combination of high inflation pressures with either low (7 - 10 Hz) or high frequencies (18 - 20 Hz), but most CF centers in the United States use HFCWO with lower pressures combined with mid-range frequencies (10 - 14 Hz). Furthermore, there are no previous studies assessing the affect of sine waveform HFCWO settings on sputum production. As a result, there is no consensus on which pressure and frequency settings are most efficacious for CF patients.

Enrollment: 17 patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

1. Diagnosis of CF established by sweat chloride > 60 mmol/L.
2. Age older than 18 years.
3. History of chronic daily sputum production.
4. Currently on a home therapeutic regimen that includes some form of airway clearance performed with a HFCWO device at least once daily that also includes concomitant use of an inhaled mucolytic and inhaled bronchodilator.
5. FVC and FEV1 > 40%-predicted, and with stable lung function (no greater than a 10% variation in lung function parameters over the preceding 3 months).
6. Evaluated at the University of Minnesota CF Center 3 or more times in the preceding 12 months.

Exclusion criteria

1. Hospitalization for CF pulmonary complications in the 2 months preceding enrollment.
2. Hemoptysis > 60 cc in a single episode in the 4 weeks preceding enrollment.
3. Chest pain requiring use of narcotic for pain control.
4. Current participation in another clinical trial.
5. Use of intravenous antibiotics for CF respiratory complications in the 2 months preceding enrollment.
6. No prior experience using HFCWO devices for airway clearance

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Triple Blind

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17 participants in 2 patient groups

HFCWC with higher pressure/variable frequency settings

Active Comparator group

Description:

Half patients randomly assigned to perform HFCWC therapy first with a higher pressure/variable frequency protocol. This entailed performing a 30 minute session with pressure of 10 and 5 minutes each at frequencies of 8,9, and 10 Hz followed by pressure of 6 and 5 minutes each at frequencies of 18, 19, and 20 Hz. This group subsequently crossed-over to the lower-pressure/mid-frequency HFCWC protocol after a washout period of 2 days. This entailed performing a HFCWC session using a pressure of 5 and frequency of 12 Hz for the entire 30 minute session. The other half of subjects were randomly assigned to perform the lower-pressure/mid-frequency protocol first followed by the higher pressure/mixed-frequency after the 2 day washout period

Treatment:

Device: HFCWC with higher pressure/variable-frequency settings

Device: HFCWC with lower pressure/mid-frequency settings

HFCWC with lower pressure/mid-frequency settings

Active Comparator group

Description:

lower-pressure/mid-frequency protocol first followed by the higher pressure/mixed-frequency

Treatment:

Device: HFCWC with higher pressure/variable-frequency settings

Device: HFCWC with lower pressure/mid-frequency settings