High-frequency and low-frequency chest compression: effects on lung water secretion, mucus transport, heart rate, and blood pressure using a trapezoidal source pressure waveform.

High-frequency chest compression (HFCC), using an appropriate source (pump) waveform for frequencies at or above 3 Hz, can enhance pulmonary clearance for patients with cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). Using a trapezoidal HFCC source pressure waveform, secretion of water from epithelial tissue and transport of mucus through lung airways can be enhanced for patients with CF and COPD. At frequencies below 3 Hz, low-frequency chest compression (LFCC) appears to have a significant impact on the cardiovascular system.

A simulation tool to study high-frequency chest compression energy transfer mechanisms and waveforms for pulmonary disease applications.

High-frequency chest compression (HFCC) can be used as a therapeutic intervention to assist in the transport and clearance of mucus and enhance water secretion for cystic fibrosis patients. An HFCC pump-vest and half chest-lung simulation, with 23 lung generations, has been developed using inertance, compliance, viscous friction relationships, and Newton's second law. The simulation has proven to be useful in studying the effects of parameter variations and nonlinear effects on HFCC system performance and pulmonary system response.

Induced respiratory system modeling by high frequency chest compression using lumped system identification method.

High frequency chest compression (HFCC) treatment systems are used to promote mucus transport and mitigate pulmonary system clearance problems to remove sputum from the airways in patients with Cystic Fibrosis (CF) and at risk of developing chronic obstructive pulmonary disease (COPD). Every HFCC system consists of a pump generator, one or two hoses connected to a vest, to deliver the pulsation. There are three different waveforms in use; symmetric sine, the asymmetric sine and the trapezoid waveforms.

Detecting changes in respiratory patterns in high frequency chest compression therapy by single-channel blind source separation.

High Frequency Chest Compression (HFCC) is used as a method to remove the mucus in the airway for Cystic Fibrosis (CF) patients. As the characteristics of the tracheal sound reflect the conditions of airways, in this paper, we propose a novel method to evaluate the respiratory patterns in HFCC therapy by using single channel tracheal sounds only. The difficulty of analyzing tracheal sounds lies in that it has a wider frequency band than the air flow at the mouth, and is always corrupted by other biomedical signals and noises.

Free-knot spline model for analysis of pulmonary function.

The pulmonary function test (PFT) is used to evaluate and monitor respiratory function. The PFT is critical for the care of patients having cystic fibrosis (CF) and adjusting their clinical treatments. We analyzed the percent predicted value of forced expiratory volume in one second (FEV(1)%) from PFT of CF patients collected four times a year from 1966.

High frequency chest compression effects on cardio-respiratory interaction.

In this study, we present a quantitative approach to the analysis of the HFCC effect on heart rate changes in the respiratory stage according to different pulsation conditions with HFCC pulsation and without HFCC pulsation. We have shown that the heart rate increases with higher pressure settings revealing different patterns depending on the respiration stages. For our interaction study of how the heart and lungs were affected by HFCC, phase synchronization was considered and compared under different conditions which determine the real biological phenomenon for nonlinear or linear oscillatory coupling.

An international/multicentre report on patients with cystic fibrosis (CF) over the age of 40 years.

Background: The lifespan of patients with cystic fibrosis (CF) is increasing significantly. The objective of this international pilot study was to study the characteristics of these long-term survivors.

Methods: Four centres with large CF clinics from London (UK), Minneapolis (USA), Toronto (Canada) and Verona (Italy) identified 366 patients who had survived 40 years and longer.

The comparison of three high-frequency chest compression devices.

High-frequency chest compression (HFCC) is shown to enhance clearance of pulmonary airway secretions. Several HFCC devices have been designed to provide this therapy. Standard equipment consists of an air pulse generator attached by lengths of tubing to an adjustable, inflatable vest/jacket (V/J) garment.

Two models of high frequency chest compression therapy: interaction of jacket pressure and mouth airflow.

High frequency chest compression (HFCC) therapy assists clearing the secretions in the lung. This paper presents two mathematical models: 1) HFCC jacket function model (JFM) and 2) respiratory function model (RFM). JFM predicts the variation of the jacket pressure (Pj) from the respiratory pattern of mouth airflow (Fm).

High frequency chest compression effects heart rate variability.

High frequency chest compression (HFCC) supplies a sequence of air pulses through a jacket worn by a patient to remove excessive mucus for the treatment or prevention of lung disease patients. The air pulses produced from the pulse generator propagates over the thorax delivering the vibration and compression energy. A number of studies have demonstrated that the HFCC system increases the ability to clear mucus and improves lung function.

Different frequencies should be prescribed for different high frequency chest compression machines.

High frequency chest compression (HFCC) is used for treatment and prevention of the lung diseases characterized by impaired mucus clearance and/or cough, where patients are at risk for acquiring acute bronchitis or pneumonia. The HFCC treatment frequencies may be prescribed according to the manufacturers' generic guidelines or may be determined for each individual patient by a "tuning" method that measures, at the mouth, the air volume displacement and the associated airflows produced at each frequency. Tuning is performed while the patient is breathing normally during the HFCC system operation.

Investigation of non-uniform airflow signal oscillation during high frequency chest compression.

Background: High frequency chest compression (HFCC) is a useful and popular therapy for clearing bronchial airways of excessive or thicker mucus. Our observation of respiratory airflow of a subject during use of HFCC showed the airflow oscillation by HFCC was strongly influenced by the nonlinearity of the respiratory system. We used a computational model-based approach to analyse the respiratory airflow during use of HFCC.

Comparison of expectorated sputum after manual chest physical therapy and high-frequency chest compression.

This study is a quantitative comparison of the sputum produced by 12 subjects with cystic fibrosis (CF) who received high-frequency chest compression (HFCC) and standard chest physical therapy (CPT) in randomized order. Six subjects routinely used manual CPT and six routinely used the HFCC. None had acute infections or hospitalization in the six weeks before the study.

High-frequency chest compression: effect of the third generation compression waveform.

High-frequency chest compression (HFCC) therapy has become the prevailing form of airway clearance for patients with cystic fibrosis (CF) in the United States. The original square waveform was replaced in 1995 with a sine waveform without published evidence of an equality of effectiveness. The recent development of a triangle waveform for HFCC provided the opportunity to compare the functional and therapeutic effects of different waveforms.

Surgical experience in patients with cystic fibrosis: a 25-year perspective.

The spectrum of surgical diseases in patients with cystic fibrosis (CF) has not been comprehensively studied. A retrospective review of 792 consecutive patients with CF presenting over a 25 year period (1970-1994) was made to determine the incidence of operations, procedures performed, complications encountered, and impact on physical development and pulmonary function tests (PFTs). A total of 191 operations were performed on 130 (16%) of the 792 patients; 98 operations (51%) were abdominal, 58 (30%) thoracic, and 31 (16%) hernias; 64 were male, and 66 female; average age was 14 +/- 10 years.