Effects of High-Frequency Chest Wall Oscillation on Pleural Pressure and Oscillated Flow

Abstract The effectiveness of high-frequency chest wall oscillation (HF-CWO) is directly related to the level of oscillated flow (vosc) in the airways. We used the Vest™ system to investigate the effects of HFCWO on chest wall and pleural pressures and we correlated these pressures to the resultant vosc. We also compared the latest HFCWO device with it predecessor. Different combinations of vest inflation pressure (background pressure) and oscillation frequency were randomly applied to 10 healthy volunteers. Chest wall pressure was determined using an air-filled bag under the vest and pleural pressure was estimated using an esophageal balloon. Reverse plethysmography was used to measure vosc at the mouth and a spirometer was used to measure changes in end-expired lung volume. We found a significant correlation between chest wall and pleural pressure with approximately one-third of the chest wall pressure transmitted into the pleural space. Mean esophageal pressure remained negative at all background pressure/frequency combinations. There was a significant correlation (p<0.0001) between the esophageal pulse pressure and vosc, which was highest at 15Hz regardless of the background pressure. The end-expired lung volume correlated with mean chest wall pressure. There was no significant difference between the two Vest™ systems. Since vosc dictates the effectiveness of HFCWO and since vosc is dependent on esophageal pulse pressure, which in turn is dependent on chest wall pulse pressure, it follows that the effectiveness of HFCWO is influenced by the ability to generate an effective chest wall pulse pressure.

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Lung pressures and gas transport during high-frequency airway and chest wall oscillation

Journal of Applied Physiology ◽

10.1152/jappl.1989.67.3.985 ◽

1989 ◽

Vol 67 (3) ◽

pp. 985-992 ◽

Cited By ~ 1

Author(s):

M. C. Khoo ◽

T. H. Ye ◽

N. H. Tran

Keyword(s):

Chest Wall ◽

Lung Volume ◽

High Frequency ◽

Blood Gases ◽

Small Degree ◽

Conventional Mechanical Ventilation ◽

Positive Pressure ◽

Arterial Blood ◽

Residual Capacity ◽

Wall Oscillation

The major goal of this study was to compare gas exchange, tidal volume (VT), and dynamic lung pressures resulting from high-frequency airway oscillation (HFAO) with the corresponding effects in high-frequency chest wall oscillation (HFCWO). Eight anesthetized paralyzed dogs were maintained eucapnic with HFAO and HFCWO at frequencies ranging from 1 to 16 Hz in the former and 0.5 to 8 Hz in the latter. Tracheal (delta Ptr) and esophageal (delta Pes) pressure swings, VT, and arterial blood gases were measured in addition to respiratory impedance and static pressure-volume curves. Mean positive pressure (25–30 cmH2O) in the chest cuff associated with HFCWO generation decreased lung volume by approximately 200 ml and increased pulmonary impedance significantly. Aside from this decrease in functional residual capacity (FRC), no change in lung volume occurred as a result of dynamic factors during the course of HFCWO application. With HFAO, a small degree of hyperinflation occurred only at 16 Hz. Arterial PO2 decreased by 5 Torr on average during HFCWO. VT decreased with increasing frequency in both cases, but VT during HFCWO was smaller over the range of frequencies compared with HFAO. delta Pes and delta Ptr between 1 and 8 Hz were lower than the corresponding pressure swings obtained with conventional mechanical ventilation (CMV) applied at 0.25 Hz. delta Pes was minimized at 1 Hz during HFCWO; however, delta Ptr decreased continuously with decreasing frequency and, below 2 Hz, became progressively smaller than the corresponding values obtained with HFAO and CMV.

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Effects of Changes in Lung Volume on Oscillatory Flow Rate During High-Frequency Chest Wall Oscillation

Canadian Respiratory Journal ◽

10.1155/2007/514573 ◽

2007 ◽

Vol 14 (3) ◽

pp. 153-158 ◽

Cited By ~ 2

Author(s):

Scott J Butcher ◽

Michal P Pasiorowski ◽

Richard L Jones

Keyword(s):

Airway Obstruction ◽

Chest Wall ◽

Flow Rate ◽

Lung Volume ◽

High Frequency ◽

Healthy Subjects ◽

Oscillatory Flow ◽

Airway Disease ◽

Wall Oscillation ◽

Oscillation Frequencies

BACKGROUND: The effectiveness of high-frequency chest wall oscillation (HFCWO) in mucolysis and mucous clearance is thought to be dependant on oscillatory flow rate (Fosc). Therefore, increasing Fosc during HFCWO may have a clinical benefit.OBJECTIVES: To examine effects of continuous positive airway pressure (CPAP) on Fosc at two oscillation frequencies in healthy subjects and patients with airway obstruction.METHODS: Five healthy subjects and six patients with airway obstruction underwent 12 randomized trials of HFCWO (CPAP levels of 0 cm H2O, 2 cm H2O, 4 cm H2O, 6 cm H2O, 8 cm H2O and 10 cm H2O at frequencies of 10 Hz and 15 Hz) within a body plethysmograph, allowing measurements of changes in lung volume. Fosc was measured by reverse plethysmography using a 20 L isothermic chamber near the mouth. At the end of each randomized trial, an inspiratory capacity manoeuvre was used to determine end-expiratory lung volume (EELV).RESULTS: EELV increased significantly (P<0.05) with each level of CPAP regardless of oscillation frequency. Fosc also significantly increased with CPAP (P<0.05) and it was correlated with EELV (r=0.7935, P<0.05) in obstructed patients but not in healthy subjects (r=0.125, P=0.343). There were no significant differences in perceived comfort across the levels of CPAP.CONCLUSIONS: Significant increases in Fosc with CPAP-induced increases in lung volume were observed, suggesting that CPAP may be useful as a therapeutic adjunct in patients who have obstructive airway disease and who require HFCWO.

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What Is the Best Pulmonary Physiotherapy Method in ICU?

Canadian Respiratory Journal ◽

10.1155/2016/4752467 ◽

2016 ◽

Vol 2016 ◽

pp. 1-5 ◽

Cited By ~ 2

Author(s):

Ufuk Kuyrukluyildiz ◽

Orhan Binici ◽

İlke Kupeli ◽

Nurel Erturk ◽

Barış Gulhan ◽

...

Keyword(s):

Chest Wall ◽

High Frequency ◽

Pulmonary Rehabilitation ◽

Apache Ii ◽

Control Group ◽

Study Group ◽

Lung Collapse ◽

Significant Difference ◽

Wall Oscillation ◽

Collapse Index

Objective. Effects of high frequency chest wall oscillation technique were investigated on intubated ICU patients.Background. Thirty intubated patients were included in the study. The control group (n=15) received routine pulmonary rehabilitation technique. In addition to the pulmonary rehabilitation technique, the study group (n=15) was given high frequency chest wall oscillation (HFCWO). APACHE II, dry sputum weight, lung collapse index, and blood gas values were measured at 24th, 48th, and 72nd hours and endotracheal aspirate culture was studied at initial and 72nd hour. The days of ventilation and days in ICU were evaluated.Results. There is no significant difference between APACHE II scores of groups. The dry sputum weights increased in the study group at 72nd hour (p=0.001). The lung collapse index decreased in study group at 48th (p=0.003) and 72nd hours (p<0.001). The PO2levels increased in the study group at 72nd hour (p=0.015). The culture positivity at 72nd hour was decreased to 20%. The days of ventilation and staying in ICU did not differ between the groups.Conclusions. Although HFCWO is very expensive equipment, combined technique may prevent the development of lung atelectasis or hospital-acquired pneumonia more than routine pulmonary rehabilitation. It does not change intubated period and length of stay in ICU. However, more further controlled clinical studies are needed to use it in ICU.

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CNE Article: Pain After Lung Transplant: High-Frequency Chest Wall Oscillation vs Chest Physiotherapy

American Journal of Critical Care ◽

10.4037/ajcc2013869 ◽

2013 ◽

Vol 22 (2) ◽

pp. 115-124 ◽

Cited By ~ 4

Author(s):

Angeli Esguerra-Gonzalez ◽

Monina Ilagan-Honorio ◽

Stephanie Fraschilla ◽

Priscilla Kehoe ◽

Ai Jin Lee ◽

...

Keyword(s):

Chest Wall ◽

High Frequency ◽

Repeated Measures ◽

Lung Transplant ◽

Chest Physiotherapy ◽

Transplant Recipients ◽

Pain Scores ◽

Significant Difference ◽

Wall Oscillation ◽

Lung Transplant Recipients

Background Chest physiotherapy and high-frequency chest wall oscillation (HFCWO) are routinely used after lung transplant to facilitate removal of secretions. To date, no studies have been done to investigate which therapy is more comfortable and preferred by lung transplant recipients. Patients who have less pain may mobilize secretions, heal, and recover faster. Objectives To compare effects of HFCWO versus chest physiotherapy on pain and preference in lung transplant recipients. Methods In a 2-group experimental, repeated-measures design, 45 lung transplant recipients (27 single lung, 18 bilateral) were randomized to chest physiotherapy (10 AM, 2 PM) followed by HFCWO (6 PM, 10 PM; group 1, n=22) or vice versa (group 2, n=23) on postoperative day 3. A verbal numeric rating scale was used to measure pain before and after treatment. At the end of the treatment sequence, a 4-item patient survey was administered to assess treatment preference, pain, and effectiveness. Data were analyzed with χ2 and t tests and repeated-measures analysis of variance. Results A significant interaction was found between mean difference in pain scores from before to after treatment and treatment method; pain scores decreased more when HFCWO was done at 10 AM and 6 PM (P =.04). Bilateral transplant recipients showed a significant preference for HFCWO over chest physiotherapy (11 [85%] vs 2 [15%], P=.01). However, single lung recipients showed no significant difference in preference between the 2 treatments (11 [42%] vs 14 [54%]). Conclusions HFCWO seems to provide greater decreases in pain scores than does chest physiotherapy. Bilateral lung transplant recipients preferred HFCWO to chest physiotherapy. HFCWO may be an effective, feasible alternative to chest physiotherapy. (American Journal of Critical Care. 2013;22:115–125)

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Utility of vest high frequency chest wall oscillation device versus flutter device in acute exacerbation of chronic obstructive pulmonary disease

International Journal of Research in Medical Sciences ◽

10.18203/2320-6012.ijrms20175703 ◽

2017 ◽

Vol 6 (1) ◽

pp. 1 ◽

Cited By ~ 1

Author(s):

Taghreed S. Farag ◽

Mariam EL-Syed

Keyword(s):

Chest Wall ◽

High Frequency ◽

Post Treatment ◽

Walking Distance ◽

Control Group ◽

Chronic Obstructive ◽

University Hospitals ◽

Obstructive Pulmonary Disease ◽

Significant Difference ◽

Wall Oscillation

Background: Objectives to assess the effectiveness of high frequency chest wall oscillation (HFCWO) vest system and Flutter devices in the treatment of patients with AECOPD, and to compare the efficacy of HFCWO vest system versus Flutter devices.Methods: We conducted an interventional study on 108 out of 129 patients presented with AECOPD, recruited from two-university hospitals. They were classified into three groups, HFCWO group (n=37), Flutter group (n=35), and control group (n=36). The HFCWO group and Flutter group were treated with AECOPD medications in addition to either HFCWO or Flutter physiotherapy, three sessions per week, for four weeks, while control group was treated by medications only. All patients were evaluated before and after treatment by spirometry, ABG, CAT score, and the BODE index.Results: Post treatment assessment for both HFCWO and Flutter groups demonstrated that most of spirometric indices (FEV1%, FVC%, FEV1/FVC %), oxygenations parameters (PaO2, SaO2 %) and CAT score, were significantly improved (p < 0.05). The level of perceived dyspnea decreased significantly, walking distance during 6-MWT was extended significantly, the BODE index and MMRC scale decreased significantly. While in control group only oxygenations parameters (PaO2, SaO2 %) was mildly improved. No statistical significant difference was found between vest HFCWO and Flutter device in all measured post treatment parameters (p > 0.05).Conclusions: Both vest HFCWO and Flutter device are highly effective in treatment of patients with AECOPD in terms of improvement in ventilatory function and oxygenation parameters with better exercise tolerance.

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