Pilot Study: Understanding the Effects of Voicing Intervention on HFCC Therapy in People with Cystic Fibrosis

The efficacy of High-Frequency Chest Compression (HFCC) airway clearance therapy is linked to the induced-peak expiratory airflow pulse (IPEF) at the patient's mouth. The authors' goal was to determine the conditions that yield the highest IPEF using HFCC running at 6 Hz in conjunction with voicing intervention. A pilot experimental study was conducted in a laboratory setting. Six adults with moderate to mild cystic fibrosis (CF) and 10 healthy adults participated. When the component characteristics of voicing were disregarded in data analysis of four conditions, voicing only intervention (V1I0), HFCC only intervention (V0I1), voicing intervention and HFCC intervention combinations (V1I1) and nonintervention (V0I0), V0I1 had significantly higher (P < 0.0001) IPEF. Data analyses of 64 separate voicing component characteristics, frequency (×4), amplitude (×4), and rhythm (×2) of voicing intervention, in addition to absence and presence of HFCC intervention (V1I0 and V1I1), were examined. One condition in V1I0 had significantly higher (P < 0.000001) IPEF than other conditions in V1I0 and V1I1 in both experimental and control groups. Based on these findings, V1I1 may yield higher IPEF than V0I1. One condition of amplitude component of voicing and one condition of rhythm component of voicing had significantly higher (P < 0.0001) IPEF than other conditions of amplitude and rhythm components in both CF and control subjects. Analysis of this combined condition of V1I1 showed that this specific condition of V1I1 had significantly higher (P < 0.000001) IPEF than any other conditions in V1I1 and V0I1.