The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts


Dabney M. Eidson2, Andrew J. Mazzoli1, Patricia Hall1; 1Respiratory Therapy, Medical College of Georgia, Augusta, GA; 2Respiratory Therapy, MCGHealth Children’s Medical Center, Augusta, GA

BACKGROUND: The high-frequency chest wall oscillator (HFCWO) is used to perform airway clearance therapy in patients with cystic fibrosis (CF). Since siblings may be affected by CF and payor reimbursement may be limited to one oscillator per household, patients have connected two vests in series for simultaneous therapy to save time. We tested the ability of The Vest® Airway Clearance System HFCWO (Hill-Rom, St. Paul, Minnesota) to deliver pressure to two subjects simultaneously as effectively as to one subject. METHODS: Two mannequins, same manufacturer and model, were fitted with appropriate sized vests. Pressure and frequency were set on 5 and 13 respectively. Multiple trials of 10 runs lasting 5 minutes per run were performed on the individual mannequins (controls). Multiple trials were then conducted on two mannequins simultaneously (study setup) with vests connected in series via a hose from the oscillator to one vest, a hose connecting the vests, and a hose from the second vest back to the oscillator. Pressure generated on the surface of each mannequin was measured via an intra-esophageal balloon placed between the mannequin and each vest. Position of the mannequins relative to the two oscillator ports was tested as were hose configurations. After 5 minutes of oscillation for each run, esophageal balloon peak pressure and trough pressure measurements were recorded for each oscillatory cycle during one second (13 cycles). The mean change between the peak pressure and trough pressure for 13 cycles was calculated. The means of the study setups were compared to means in the controls using a two-sample t-test. RESULTS: The mean pressure was significantly lower (p< 0.0001) in the study setup, with vests connected in series, than in the controls regardless of mannequin position or hose configuration. CONCLUSION: In this study, the use of “The Vest®” HFCWO with two vests simultaneously, connected in series, resulted in a decrease in performance compared to use with a single vest, as measured by the difference in peak and trough pressures at the surface of the mannequin. While simultaneous treatment of CF siblings may save time, doing so may decrease efficacy. Therefore, further investigation of oscillator performance by using increased pressure settings to compensate for pressure drop, using parallel circuitry, testing similar devices made by other manufacturers, and demonstrating the clinical significance of decreased pressure is warranted. Sponsored Research - None