Comparison of settings used for high-frequency chest-wall compression in cystic fibrosis.

Respir Care. 2010 Jun;55(6):695-701.

Comparison of settings used for high-frequency chest-wall compression in cystic fibrosis.

Kempainen RR, Milla C, Dunitz J, Savik K, Hazelwood A, Williams C, Rubin BK, Billings JL.
Department of Medicine, Hennepin County Medical Center, University of Minnesota School of Medicine, Mail Stop G-5, 701 Park Avenue, Minneapolis MN 55415. kempa001@umn.edu.

Abstract

BACKGROUND: Cystic fibrosis (CF) patients commonly use a high-frequency chest-wall compression (HFCWC) device for airway clearance that generates oscillatory flow with a sine-wave configuration. Typical HFCWC settings combine a lower Vest inflation pressure setting (eg, 5 on the Vest's arbitrary 1-10 scale for the setting that controls the background pressure of the inflatable vest) with mid-range frequency (14-16 Hz) (lower-pressure/mid-frequency HFCWC). OBJECTIVE: To determine whether HFCWC with higher pressure settings (6-10 on the Hill-Rom Vest's arbitrary 1-10 scale) combined with variable mid-frequencies (8, 9, and 10 Hz, plus 18, 19, and 20 Hz) (higher-pressure/variable-frequency HFCWC) results in greater sputum expectoration than lower-pressure/mid-frequency HFCWC.

METHODS: This was a controlled randomized crossover study. Sixteen clinically stable, adult CF patients participated. Patients performed airway clearance with HFCWC, once each with lower-pressure/mid-frequency HFCWC and higher-pressure/variable-frequency HFCWC, on separate occasions. All sputum produced during each session was collected. Patients completed pulmonary function tests before and after each session.

RESULTS: Median sputum wet weight was greater with higher-pressure/variable-frequency HFCWC than with lower-pressure/mid-frequency HFCWC (6.4 g, range 0.49-22.0 g, versus 4.8 g, range 0.24-15.0 g, P = .02). Dry sputum weight differences did not reach statistical significance (higher-pressure/variable-frequency HFCWC 0.20 g, range 0.009-0.62 g, lower-pressure/mid-frequency HFCWC 0.12 g, range 0.0001-1.0 g, P = .23). Higher-pressure/variable-frequency HFCWC and lower-pressure/mid-frequency HFCWC resulted in similar increases in FEV(1) (70 mL vs 90 mL, P = .21) and forced vital capacity (80 mL vs 80 mL, P = .94). Post-therapy sputum viscoelastic properties did not differ. Patients perceived the 2 regimens as equally comfortable and effective (P = .35 and P = .35, respectively).

CONCLUSIONS: In adult CF patients, single-session higher-pressure/variable-frequency HFCWC resulted in greater sputum expectoration by wet weight, but not other differences, compared to the commonly used lower-pressure/mid-frequency settings. Longer-term comparisons are needed in a larger, more diverse population to determine whether sustained use of the higher-pressure/variable-frequency settings results in clinically important differences in outcomes.

(Clinicaltrials.gov registration NCT00685035).

High Frequence Chest Wall Oscillation and Cystic Fibrosis study in the UK

Wow I feel so fortunate to have had HFCC available to me for a very low cost since 1997.....

High Frequence Chest Wall Oscillation and Cystic Fibrosis

This study is not yet open for participant recruitment.

Verified by Imperial College London, January 2010

Sponsor: Imperial College London

Collaborators: Royal Brompton & Harefield NHS Foundation TrustHill-Rom

Purpose : High frequency chest wall oscillation (HFCWO) has been shown to increase tracheal mucus clearance compared with a control group. These observations led to the development of The Vest® which is a non-stretchable jacket connected to an air-pulse generator and worn by the patient over the chest wall. The generator rapidly inflates and deflates The Vest®, which gently compresses and releases the chest wall between 5 and 20 times per second. This generates mini-coughs that are said to dislodge mucus from the bronchial walls and to facilitate its movement up the airways. The Vest® has been shown to reduce the viscosity of mucus and this should further enhance mucus clearance.

People with cystic fibrosis (CF), admitted to hospital with an acute infective pulmonary exacerbation, should increase the frequency and duration of their airway clearance sessions owing to the increase in quantity and viscosity of purulent bronchial secretions.In the United Kingdom, and in many other countries, the availability of physiotherapists to assist with the recommended number of daily treatments is insufficient to meet patient need. If the use of high frequency chest wall oscillation, in addition to 'usual' self airway clearance techniques, in the early morning and evening was to facilitate recovery from an exacerbation, this would indicate an important place for high frequency chest wall oscillation in the management of people with cystic fibrosis.

Hypothesis: The addition of high frequency chest wall oscillation to twice daily supervised physiotherapy is as effective as the addition of self treatment in facilitating recovery from an acute infective pulmonary exacerbation, as measured by improvement in lung function, specifically forced expiratory volume in one second (FEV1).

Device: High Frequency Chest Wall Oscillation (HFCWO)

Other: Usual airway clearance

Study Design: Treatment, Randomized, Open Label, Parallel Assignment, Efficacy Study

Official Title:The Use of High Frequency Chest Wall Oscillation During an Acute Infective Pulmonary Exacerbation of Cystic Fibrosis

Primary Outcome Measures:
Mean percentage change in forced expiratory volume in one second (FEV1) [ Time Frame: 7days ] [ Designated as safety issue: Yes ]

Secondary Outcome Measures:
Wet weight of sputum expectorated [ Time Frame: 24 hours ] [ Designated as safety issue: Yes ]
Length of time to next course of intravenous antibiotics [ Time Frame: Within 6 monthsof completing study ] [ Designated as safety issue: Yes ]
Rate of change of C-reactive protein [ Time Frame: 7 days ] [ Designated as safety issue: Yes ]

Estimated Enrollment: 56

Study Start Date: February 2010

Estimated Study Completion Date: July 2011

Estimated Primary Completion Date: July 2011 (Final data collection date for primary outcome measure)

Usual Airway Clearance Technique: Active Comparator

Two self administered treatment sessions a day and two treatments a day assisted by a Physiotherapist both using the patient's usual airway clearance method.

Other: Usual airway clearance
Airway clearance treatments using the active cycle of breathing techniques, autogenic drainage, positive expiratory pressure, manual techniques or oscillating positive expiratory pressure

High Frequency Chest Wall Oscillation (HFCWO): Experimental
Two self administered treatments a day using HFCWO and two treatment sessions a day assisted by a Physiotherapist using their 'usual' airway clearance method.

Device: High Frequency Chest Wall Oscillation (HFCWO)
Airway clearance using the high frequency chest wall oscillator device

Contacts
Contact: Elizabeth A Banks, MSc
0207 351 8935
e.banks@imperial.ac.uk
Contact: Penny Agent
0207 352 8121 ext 8056

Locations

United Kingdom
Royal Brompton & Harefield NHS Foundation Trust
London, United Kingdom

Sponsors and Collaborators
Imperial College London
Royal Brompton & Harefield NHS Foundation Trust
Hill-Rom

Investigators

Principal Investigator:
Margaret Hodson
Imperial College London