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

• Sponsor: University of Minnesota (Other)
• Overall Status: Completed
• CT.gov ID: NCT00685035
• Collaborator: Hill-Rom (Industry)
• Enrollment: 17
• Location: 1
• Arms: 2
• Duration (Months): 5
• Patients Per Site Per Month: 3.4

Study Details

Study Description

Brief Summary

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.

Condition or Disease	Intervention/Treatment	Phase
Cystic Fibrosis	Device: HFCWC with higher pressure/variable-frequency settings; Device: HFCWC with lower pressure/mid-frequency settings	Phase 4

Detailed 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.

Study Design

• Study Type: Interventional
• Actual Enrollment: 17 participants
• Allocation: Randomized
• Intervention Model: Crossover Assignment
• Masking: Triple (Participant, Investigator, Outcomes Assessor)
• Primary Purpose: Treatment
• Official Title: Comparison of Sine Waveform High Frequency Chest Wall Oscillation Using Different Settings in Cystic Fibrosis
• Study Start Date: May 1, 2008
• Actual Primary Completion Date: Aug 1, 2008
• Actual Study Completion Date: Oct 1, 2008

Arms and Interventions

Arm	Intervention/Treatment
Active Comparator: HFCWC with higher pressure/variable frequency settings 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	Device: HFCWC with higher pressure/variable-frequency settings; Randomized crossover trial of airway clearance therapy comparing sine wave HFCWO with high pressures and variable frequency (pressure 10, frequencies 8,9,10 and pressure 6, frequencies 18,19,20) to low pressure and mid frequency (pressure 5, frequency 12). Subjects will have 2-day washout between airway clearance sessions. All sputum collected during sessions.; Other Names: High frequency chest wall oscillation ; Device: HFCWC with lower pressure/mid-frequency settings; Subjects will perform pulmonary function tests prior to and following each airway clearance therapy. All sputum produced during, and for 15 minutes following airway clearance therapy will be collected. Subjects will complete a questionnaire addressing the comfort of therapy upon completion of the session.; Other Names: high frequency chest wall oscillation
Active Comparator: HFCWC with lower pressure/mid-frequency settings lower-pressure/mid-frequency protocol first followed by the higher pressure/mixed-frequency	Device: HFCWC with higher pressure/variable-frequency settings; Randomized crossover trial of airway clearance therapy comparing sine wave HFCWO with high pressures and variable frequency (pressure 10, frequencies 8,9,10 and pressure 6, frequencies 18,19,20) to low pressure and mid frequency (pressure 5, frequency 12). Subjects will have 2-day washout between airway clearance sessions. All sputum collected during sessions.; Other Names: High frequency chest wall oscillation ; Device: HFCWC with lower pressure/mid-frequency settings; Subjects will perform pulmonary function tests prior to and following each airway clearance therapy. All sputum produced during, and for 15 minutes following airway clearance therapy will be collected. Subjects will complete a questionnaire addressing the comfort of therapy upon completion of the session.; Other Names: high frequency chest wall oscillation

Outcome Measures

Primary Outcome Measures

1. Sputum Wet and Dry Weight [Produced during each airway clearance therapy session on days 1 and 4]

   All sputum expectorated during all HFCWC sessions was collected in a pre-weighed specimen container and immediately sealed. Half the subjects used higher pressure/mixed frequency on day 1 followed by lower pressure/mid-frequency on day 4. Half the patients performed lower pressure/mid-frequency on day 1 followed by higher pressure/mixed frequency on day 4. All specimens were immediately centrifuged at 21,150 g for 15 min at 4°C, and the supernatant was completely removed to eliminate saliva. The sputum "wet weight" was calculated after re-weighing the container with the sputum pellet. The container was then left open in an oven with the temperature set at 65°C for a minimum of 3 days to allow for complete desiccation. The sputum "dry weight" was calculated after re-weighing the container.

Secondary Outcome Measures

1. Pre vs. Post Therapy Spirometry [Prior to and following each airway clearance therapy session on days 1 and 4]

   Spirometry was performed prior to, and immediately following, all HCWC sessions on Day 1. Spirometry was performed immediately prior to, and immediately following, all HFCWC sessions on Day 4. Spirometry was performed according to American Thoracic Society/European Respiratory Society standards.

2. Rheology and in Vitro Cough Transportability of Sputum Produced Immediately Following Airway Clearance Therapy Session [Sputum produced during the 15 minutes immediately following airway clearance therapy sessions on day 1 and day 4]

   Sputum was collected during the 15 minutes immediately following HFCWC sessions on day 1 and day 4. Half the subjects performed higher-pressure/mixed frequency HFCWC on Day 1 followed by lower pressure/mid-frequency HFCWC on Day 4. The other half of subjects performed lower pressure/mid-frequency on Day 1 followed by higer pressure/mixed-frequency on Day 4. Samples were studied with a rheometer (AR1000, TA Instruments, New Castle, Delaware) to assess the dynamic frequency range of stress-strain of a 20 microliter sputum sample over driving frequencies of 1-100 rad/s. Shear storage modulus (G') and shear loss modulus (G") were determined from these curves after nondestructive creep transformation. G' (or dynamic elasticity) measures stored energy and is a property of ideal solids. G" is directly proportional to viscosity (viscosity x frequency) and is a property of ideal liquids.

3. Patients' Perceived Comfort Using the Different Settings for the Vest Device [Immediately following each airway clearance therapy on day 1 and day 4]

   Following each HFCWC session on day 1 and day 4, subjects completed a questionnaire that rated the comfort and efficacy of each HFCWC session using a 5-point scale. The questionnaire was entitled "Post-Therapy Questionnaire". Scale range for comfort ranged from 1 (very uncomfortable) to 3 (neutral) to 5 (very comfortable). Scale range for how "effective" the HFCWC session was ranged from 1 (minimally effective) to 3 (neutral) to 5 (very effective).

Eligibility Criteria

Criteria

• Ages Eligible for Study: 18 Years and Older
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: No

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

Contacts and Locations

Locations

	Site	City	State	Country	Postal Code
1	University of Minnesota Medical Center	Minneapolis	Minnesota	United States	55455

Sponsors and Collaborators

• University of Minnesota
• Hill-Rom

Investigators

• Principal Investigator: Robert R Kempainen, MD, University of Minnesota

Study Documents (Full-Text)

None provided.

More Information

Publications

None provided.

• Responsible Party: University of Minnesota
• ClinicalTrials.gov Identifier: NCT00685035
• Other Study ID Numbers: 0802M26441
• First Posted: May 28, 2008
• Last Update Posted: Jul 25, 2016
• Last Verified: Jun 1, 2016

• Keywords provided by University of Minnesota: high frequency chest wall oscillation, cystic fibrosis
• Additional relevant MeSH terms: Cystic Fibrosis; Fibrosis

Study Results

Participant Flow

Recruitment Details	Potentially eligible patients were identified by query of the Minnesota CF database based on age and FEV1. This list was then reviewed and patients who met additional eligibility requirements were contacted by phone or recruited during a clinic visit by one of the study investigators. Enrollment was completed between 6/1/08 and 10/31/08.

Arm/Group Title	Higher Pressure/Variable-freq, Then Lower Pressure/Mid-freq	Lower Pressure/Mid-freq, Then Higher Pressure/Variable-freq
Arm/Group Description	HFCWC therapy first with a higher pressure/variable frequency protocol (1st Intervention). After a washout period of 2 days, this group subsequently crossed-over to the lower-pressure/mid-frequency HFCWC protocol (2nd Intervention).	HFCWC therapy first with a lower pressure/mid-frequency protocol (1st Intervention). After a washout period of 2 days, this group subsequently crossed-over to the higher-pressure/variable frequency HFCWC protocol (2nd Intervention).
Period Title: Period 1: First Intervention: 30 Minutes
STARTED	9	8
COMPLETED	8	8
NOT COMPLETED	1	0
Period Title: Period 1: First Intervention: 30 Minutes
STARTED	8	8
COMPLETED	8	8
NOT COMPLETED	0	0
Period Title: Period 1: First Intervention: 30 Minutes
STARTED	8	8
COMPLETED	8	8
NOT COMPLETED	0	0

Baseline Characteristics

Arm/Group Title	All Study Participants
Arm/Group Description	Half patients randomly assigned to 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 VEST Airway Clearance System, Model 205 : Subjects will perform pulmonary function tests prior to and following each airway clearance therapy. All sputum produced during, and for 15 minutes following airway clearance therapy will be collected. Subjects
Overall Participants	17
Age (Count of Participants)
<=18 years	0 0%
Between 18 and 65 years	17 100%
>=65 years	0 0%
Age (years) [Mean (Standard Deviation) ]
Mean (Standard Deviation) [years]	33.3 (7.3)
Sex: Female, Male (Count of Participants)
Female	7 41.2%
Male	10 58.8%
Region of Enrollment (participants) [Number]
United States	17 100%

Outcome Measures

1. Primary Outcome

Title	Sputum Wet and Dry Weight
Description	All sputum expectorated during all HFCWC sessions was collected in a pre-weighed specimen container and immediately sealed. Half the subjects used higher pressure/mixed frequency on day 1 followed by lower pressure/mid-frequency on day 4. Half the patients performed lower pressure/mid-frequency on day 1 followed by higher pressure/mixed frequency on day 4. All specimens were immediately centrifuged at 21,150 g for 15 min at 4°C, and the supernatant was completely removed to eliminate saliva. The sputum "wet weight" was calculated after re-weighing the container with the sputum pellet. The container was then left open in an oven with the temperature set at 65°C for a minimum of 3 days to allow for complete desiccation. The sputum "dry weight" was calculated after re-weighing the container.
Time Frame	Produced during each airway clearance therapy session on days 1 and 4

Outcome Measure Data

Analysis Population Description

In a previous study with similar design,21 the standard deviation for the difference in the mean sputum wet weight between treatment arms was 4.6 g. Assuming the same standard deviation for the current study, enrollment of 16 subjects provided an 80% chance of detecting a 3.5-g difference in the sputum wet weights at a significance level of .05.

Arm/Group Title	Sputum Wet Weight Higher Pressure/Variable Frequency	Sputum Wet Weight Lower Pressure/Mid-frequency	Sputum Dry Weight Higher Pressure/Variable Frequency	Sputum Dry Weight Lower Pressure/Mid-frequency
Arm/Group Description	All sputum expectorated during all HFCWC sessions was collected in a pre-weighed specimen container and immediately sealed. Half the subjects used higher pressure/mixed frequency on day 1 followed by lower pressure/mid-frequency on day 4. Half the patients performed lower pressure/mid-frequency on day 1 followed by higher pressure/mixed frequency on day 4. All specimens were immediately centrifuged at 21,150 g for 15 min at 4°C, and the supernatant was completely removed to eliminate saliva. The sputum "wet weight" was calculated after re-weighing the container with the sputum pellet.	All sputum expectorated during all HFCWC sessions was collected in a pre-weighed specimen container and immediately sealed. Half the subjects used higher pressure/mixed frequency on day 1 followed by lower pressure/mid-frequency on day 4. Half the patients performed lower pressure/mid-frequency on day 1 followed by higher pressure/mixed frequency on day 4. All specimens were immediately centrifuged at 21,150 g for 15 min at 4°C, and the supernatant was completely removed to eliminate saliva. The sputum "wet weight" was calculated after re-weighing the container with the sputum pellet.	All sputum expectorated during all HFCWC sessions was collected in a pre-weighed specimen container and immediately sealed. Half the subjects used higher pressure/mixed frequency on day 1 followed by lower pressure/mid-frequency on day 4. Half the patients performed lower pressure/mid-frequency on day 1 followed by higher pressure/mixed frequency on day 4. All specimens were immediately centrifuged at 21,150 g for 15 min at 4°C, and the supernatant was completely removed to eliminate saliva. The container was then left open in an oven with the temperature set at 65°C for a minimum of 3 days to allow for complete desiccation. The sputum "dry weight" was calculated after re-weighing the container.	All sputum expectorated during all HFCWC sessions was collected in a pre-weighed specimen container and immediately sealed. Half the subjects used higher pressure/mixed frequency on day 1 followed by lower pressure/mid-frequency on day 4. Half the patients performed lower pressure/mid-frequency on day 1 followed by higher pressure/mixed frequency on day 4. All specimens were immediately centrifuged at 21,150 g for 15 min at 4°C, and the supernatant was completely removed to eliminate saliva. The container was then left open in an oven with the temperature set at 65°C for a minimum of 3 days to allow for complete desiccation. The sputum "dry weight" was calculated after re-weighing the container.
Measure Participants	16	16	16	15
Median (Full Range) [grams]	6.4	4.8	0.20	0.12

Statistical Analysis 1

Statistical Analysis Overview	Comparison Group Selection	Sputum Wet Weight Higher Pressure/Variable Frequency, Sputum Wet Weight Lower Pressure/Mid-frequency, Sputum Dry Weight Higher Pressure/Variable Frequency, Sputum Dry Weight Lower Pressure/Mid-frequency
	Comments
	Type of Statistical Test	Superiority or Other
	Comments
Statistical Test of Hypothesis	p-Value	.02
	Comments
	Method	ANCOVA
	Comments
Method of Estimation	Estimation Parameter	Mean Difference (Final Values)
	Estimated Value	.23
	Confidence Interval	(2-Sided) 95%; to
	Parameter Dispersion	Type: Standard Deviation; Value: .23
	Estimation Comments

2. Secondary Outcome

Title	Pre vs. Post Therapy Spirometry
Description	Spirometry was performed prior to, and immediately following, all HCWC sessions on Day 1. Spirometry was performed immediately prior to, and immediately following, all HFCWC sessions on Day 4. Spirometry was performed according to American Thoracic Society/European Respiratory Society standards.
Time Frame	Prior to and following each airway clearance therapy session on days 1 and 4

Outcome Measure Data

Analysis Population Description

Power calculation not performed for secondary outcomes.

Arm/Group Title	Change in FEV1 Pre vs Post Higher Pressure/Variable Frequency	Change in FEV1 Pre vs Post Lower Pressure/Mid-frequency	Change in FVC Pre vs Post Higher Pressure/Variable Frequency	Change in FVC Pre vs Post Lower Pressure/Mid-frequency
Arm/Group Description	Spirometry was performed prior to, and immediately following, all HCWC sessions on Day 1. Spirometry was performed immediately prior to, and immediately following, all HFCWC sessions on Day 4. Spirometry was performed according to American Thoracic Society/European Respiratory Society standards.	Spirometry was performed prior to, and immediately following, all HCWC sessions on Day 1. Spirometry was performed immediately prior to, and immediately following, all HFCWC sessions on Day 4. Spirometry was performed according to American Thoracic Society/European Respiratory Society standards.	Spirometry was performed prior to, and immediately following, all HCWC sessions on Day 1. Spirometry was performed immediately prior to, and immediately following, all HFCWC sessions on Day 4. Spirometry was performed according to American Thoracic Society/European Respiratory Society standards.	Spirometry was performed prior to, and immediately following, all HCWC sessions on Day 1. Spirometry was performed immediately prior to, and immediately following, all HFCWC sessions on Day 4. Spirometry was performed according to American Thoracic Society/European Respiratory Society standards.
Measure Participants	16	16	16	16
Mean (Standard Deviation) [ml]	70 (90)	90 (120)	80 (160)	80 (230)

3. Secondary Outcome

Title	Rheology and in Vitro Cough Transportability of Sputum Produced Immediately Following Airway Clearance Therapy Session
Description	Sputum was collected during the 15 minutes immediately following HFCWC sessions on day 1 and day 4. Half the subjects performed higher-pressure/mixed frequency HFCWC on Day 1 followed by lower pressure/mid-frequency HFCWC on Day 4. The other half of subjects performed lower pressure/mid-frequency on Day 1 followed by higer pressure/mixed-frequency on Day 4. Samples were studied with a rheometer (AR1000, TA Instruments, New Castle, Delaware) to assess the dynamic frequency range of stress-strain of a 20 microliter sputum sample over driving frequencies of 1-100 rad/s. Shear storage modulus (G') and shear loss modulus (G") were determined from these curves after nondestructive creep transformation. G' (or dynamic elasticity) measures stored energy and is a property of ideal solids. G" is directly proportional to viscosity (viscosity x frequency) and is a property of ideal liquids.
Time Frame	Sputum produced during the 15 minutes immediately following airway clearance therapy sessions on day 1 and day 4

Outcome Measure Data

Analysis Population Description

power calculation not performed for secondary outcomes

Arm/Group Title	G' Storage Modulus at 1 Rad/Sec Higher Pressure/Variable Freq	G' Storage Modulus at 1 Rad/Sec Lower Pressure/Mid-frequency	G' Storage Modulus 100 Rad/Sec Higher Pressure/Variable Freq	G' Storage Modulus 100 Rad/Sec Lower Pressure/Mid-frequency	G" Loss Modulus 1 Rad/Sec Higher Pressure/Variable Frequency	G" Loss Modulus 1 Rad/Sec Lower Pressure/Mid-frequency	G" Loss Modulus 100 Rad/Sec Higher Pressure/Variable Frequency	G" Loss Modulus 100 Rad/Sec Lower Pressure/Mid-frequency
Arm/Group Description	Sputum was collected during the 15 minutes immediately following HFCWC sessions on day 1 and day 4. Half the subjects performed higher-pressure/mixed frequency HFCWC on Day 1 followed by lower pressure/mid-frequency HFCWC on Day 4. The other half of subjects performed lower pressure/mid-frequency on Day 1 followed by higer pressure/mixed-frequency on Day 4. Samples were studied with a rheometer (AR1000, TA Instruments, New Castle, Delaware) to assess the dynamic frequency range of stress-strain of a 20 microliter sputum sample over driving frequencies of 1-100 rad/s. Shear storage modulus (G') and shear loss modulus (G") were determined from these curves after nondestructive creep transformation. G' (or dynamic elasticity) measures stored energy and is a property of ideal solids. G" is directly proportional to viscosity (viscosity x frequency) and is a property of ideal liquids.	Sputum was collected during the 15 minutes immediately following HFCWC sessions on day 1 and day 4. Half the subjects performed higher-pressure/mixed frequency HFCWC on Day 1 followed by lower pressure/mid-frequency HFCWC on Day 4. The other half of subjects performed lower pressure/mid-frequency on Day 1 followed by higer pressure/mixed-frequency on Day 4. Samples were studied with a rheometer (AR1000, TA Instruments, New Castle, Delaware) to assess the dynamic frequency range of stress-strain of a 20 microliter sputum sample over driving frequencies of 1-100 rad/s. Shear storage modulus (G') and shear loss modulus (G") were determined from these curves after nondestructive creep transformation. G' (or dynamic elasticity) measures stored energy and is a property of ideal solids. G" is directly proportional to viscosity (viscosity x frequency) and is a property of ideal liquids.	Sputum was collected during the 15 minutes immediately following HFCWC sessions on day 1 and day 4. Half the subjects performed higher-pressure/mixed frequency HFCWC on Day 1 followed by lower pressure/mid-frequency HFCWC on Day 4. The other half of subjects performed lower pressure/mid-frequency on Day 1 followed by higer pressure/mixed-frequency on Day 4. Samples were studied with a rheometer (AR1000, TA Instruments, New Castle, Delaware) to assess the dynamic frequency range of stress-strain of a 20 microliter sputum sample over driving frequencies of 1-100 rad/s. Shear storage modulus (G') and shear loss modulus (G") were determined from these curves after nondestructive creep transformation. G' (or dynamic elasticity) measures stored energy and is a property of ideal solids. G" is directly proportional to viscosity (viscosity x frequency) and is a property of ideal liquids.	Sputum was collected during the 15 minutes immediately following HFCWC sessions on day 1 and day 4. Half the subjects performed higher-pressure/mixed frequency HFCWC on Day 1 followed by lower pressure/mid-frequency HFCWC on Day 4. The other half of subjects performed lower pressure/mid-frequency on Day 1 followed by higer pressure/mixed-frequency on Day 4. Samples were studied with a rheometer (AR1000, TA Instruments, New Castle, Delaware) to assess the dynamic frequency range of stress-strain of a 20 microliter sputum sample over driving frequencies of 1-100 rad/s. Shear storage modulus (G') and shear loss modulus (G") were determined from these curves after nondestructive creep transformation. G' (or dynamic elasticity) measures stored energy and is a property of ideal solids. G" is directly proportional to viscosity (viscosity x frequency) and is a property of ideal liquids.	Sputum was collected during the 15 minutes immediately following HFCWC sessions on day 1 and day 4. Half the subjects performed higher-pressure/mixed frequency HFCWC on Day 1 followed by lower pressure/mid-frequency HFCWC on Day 4. The other half of subjects performed lower pressure/mid-frequency on Day 1 followed by higer pressure/mixed-frequency on Day 4. Samples were studied with a rheometer (AR1000, TA Instruments, New Castle, Delaware) to assess the dynamic frequency range of stress-strain of a 20 microliter sputum sample over driving frequencies of 1-100 rad/s. Shear storage modulus (G') and shear loss modulus (G") were determined from these curves after nondestructive creep transformation. G' (or dynamic elasticity) measures stored energy and is a property of ideal solids. G" is directly proportional to viscosity (viscosity x frequency) and is a property of ideal liquids.	Sputum was collected during the 15 minutes immediately following HFCWC sessions on day 1 and day 4. Half the subjects performed higher-pressure/mixed frequency HFCWC on Day 1 followed by lower pressure/mid-frequency HFCWC on Day 4. The other half of subjects performed lower pressure/mid-frequency on Day 1 followed by higer pressure/mixed-frequency on Day 4. Samples were studied with a rheometer (AR1000, TA Instruments, New Castle, Delaware) to assess the dynamic frequency range of stress-strain of a 20 microliter sputum sample over driving frequencies of 1-100 rad/s. Shear storage modulus (G') and shear loss modulus (G") were determined from these curves after nondestructive creep transformation. G' (or dynamic elasticity) measures stored energy and is a property of ideal solids. G" is directly proportional to viscosity (viscosity x frequency) and is a property of ideal liquids.	Sputum was collected during the 15 minutes immediately following HFCWC sessions on day 1 and day 4. Half the subjects performed higher-pressure/mixed frequency HFCWC on Day 1 followed by lower pressure/mid-frequency HFCWC on Day 4. The other half of subjects performed lower pressure/mid-frequency on Day 1 followed by higer pressure/mixed-frequency on Day 4. Samples were studied with a rheometer (AR1000, TA Instruments, New Castle, Delaware) to assess the dynamic frequency range of stress-strain of a 20 microliter sputum sample over driving frequencies of 1-100 rad/s. Shear storage modulus (G') and shear loss modulus (G") were determined from these curves after nondestructive creep transformation. G' (or dynamic elasticity) measures stored energy and is a property of ideal solids. G" is directly proportional to viscosity (viscosity x frequency) and is a property of ideal liquids.	Sputum was collected during the 15 minutes immediately following HFCWC sessions on day 1 and day 4. Half the subjects performed higher-pressure/mixed frequency HFCWC on Day 1 followed by lower pressure/mid-frequency HFCWC on Day 4. The other half of subjects performed lower pressure/mid-frequency on Day 1 followed by higer pressure/mixed-frequency on Day 4. Samples were studied with a rheometer (AR1000, TA Instruments, New Castle, Delaware) to assess the dynamic frequency range of stress-strain of a 20 microliter sputum sample over driving frequencies of 1-100 rad/s. Shear storage modulus (G') and shear loss modulus (G") were determined from these curves after nondestructive creep transformation. G' (or dynamic elasticity) measures stored energy and is a property of ideal solids. G" is directly proportional to viscosity (viscosity x frequency) and is a property of ideal liquids.
Measure Participants	12	12	12	12	12	12	12	12
Median (Full Range) [dynes/cm^2]	4.43	4.61	107.3	130.7	10.7	7.4	1,224	862

4. Secondary Outcome

Title	Patients' Perceived Comfort Using the Different Settings for the Vest Device
Description	Following each HFCWC session on day 1 and day 4, subjects completed a questionnaire that rated the comfort and efficacy of each HFCWC session using a 5-point scale. The questionnaire was entitled "Post-Therapy Questionnaire". Scale range for comfort ranged from 1 (very uncomfortable) to 3 (neutral) to 5 (very comfortable). Scale range for how "effective" the HFCWC session was ranged from 1 (minimally effective) to 3 (neutral) to 5 (very effective).
Time Frame	Immediately following each airway clearance therapy on day 1 and day 4

Outcome Measure Data

Analysis Population Description

power calculation not performed for secondary outcomes

Arm/Group Title	Perceived Comfort Higher Pressure/Variable Frequency	Perceived Comfort Lower Pressure/Mid-frequency	Perceived Effectiveness Higher Pressure/Variable Frequency	Perceived Effectiveness Lower Pressure/Mid-frequency
Arm/Group Description	Following each HFCWC session on day 1 and day 4, subjects completed a questionnaire that rated the comfort of each HFCWC session using a 5-point scale. The questionnaire was entitled "Post-Therapy Questionnaire". Scale range for comfort ranged from 1 (very uncomfortable) to 3 (neutral) to 5 (very comfortable).	Following each HFCWC session on day 1 and day 4, subjects completed a questionnaire that rated the comfort of each HFCWC session using a 5-point scale. The questionnaire was entitled "Post-Therapy Questionnaire". Scale range for comfort ranged from 1 (very uncomfortable) to 3 (neutral) to 5 (very comfortable).	Following each HFCWC session on day 1 and day 4, subjects completed a questionnaire that rated the comfort and efficacy of each HFCWC session using a 5-point scale. The questionnaire was entitled "Post-Therapy Questionnaire". Scale range for how "effective" the HFCWC session was ranged from 1 (minimally effective) to 3 (neutral) to 5 (very effective).	Following each HFCWC session on day 1 and day 4, subjects completed a questionnaire that rated the comfort and efficacy of each HFCWC session using a 5-point scale. The questionnaire was entitled "Post-Therapy Questionnaire". Scale range for how "effective" the HFCWC session was ranged from 1 (minimally effective) to 3 (neutral) to 5 (very effective).
Measure Participants	16	16	16	12
Median (Full Range) [units on a scale]	4.5	5	4	4

Adverse Events

Arm/Group Title	Lower Pressure/Mid-frequency		Higher Pressure/Variable Frequency
Arm/Group Description
All Cause Mortality
	Lower Pressure/Mid-frequency		Higher Pressure/Variable Frequency
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	/ (NaN)		/ (NaN)
Serious Adverse Events
	Lower Pressure/Mid-frequency		Higher Pressure/Variable Frequency
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/17 (0%)		0/16 (0%)
Other (Not Including Serious) Adverse Events
	Lower Pressure/Mid-frequency		Higher Pressure/Variable Frequency
	Affected / at Risk (%)	# Events	Affected / at Risk (%)	# Events
Total	0/17 (0%)		0/16 (0%)

Limitations/Caveats

Sputum weights varied more than anticipated and the study was underpowered to detect differences in the primary outcomes. Study not generalizable to patients that do not produce sputum or have an FEV1 < 40% predicted.

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.