The question of whether to use a cough assist or vest therapy for airway clearance in patients with Duchenne has come up several times. I connected with Drs. Richard Shell (Nationwide Children’s Hospital, Columbus, Ohio), Hemant Sawnani (Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio), and Jonathan Finder (Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania) for their expert opinions. Below is a summary of their thoughts.
“The Vest,” or “high frequency chest wall oscillation,” is a technology employing an inflatable vest connected by an air hose to a pulse generator. The vest rapidly inflates and deflates, applying gentle pulsed pressure to the chest wall. The aim is to generate “shearing force” between the mucus and the lining of the airways, with the intention of dislodging these secretions that can subsequently be coughed and cleared.
Vest therapy is ideal for patients who have conditions with abnormally thick mucus (such as cystic fibrosis, COPD, chronic bronchitis, etc). Patients with respiratory muscle weakness, however, do not typically have abnormally thick mucus. Their difficulty lies in the inability to clear mucus of normal consistency. Therefore, vest therapy is rarely appropriate for patients with Duchenne or Becker muscular dystrophy. Its use may be instituted during the recovery of an extensive pneumonia or if there is a stubborn area of collapse. That would be at the discretion of the treating physician.
The “cough assist” uses a facemask, mouthpiece, or tracheostomy to deliver gradual positive air pressure to the airway (inflation), followed by a rapid shift to negative air pressure (deflation), in an attempt to simulate a natural cough. As patients with Duchenne and Becker have difficulty clearing secretions, a cough assist is not only appropriate therapy, but is critical for maintaining pulmonary health and reducing the incidence of infections and pneumonias.
Some criticisms of the cough assist machine are that it is big, bulky, heavy, and difficult to travel with. New machines are on the market, which are smaller, lighter, and more convenient. Be sure and ask if these newer options are available through your provider. Also, these machines need to be calibrated appropriately for the patient using them. Please be sure to ask for instruction when the machine is delivered to your home.
Effective assisted cough techniques should be taught early, certainly when peak cough flow (PCF) falls below 300 lpm and/or used during a respiratory illness. For more information regarding cough assist, please visit the PPMD website.
And for more pulmonary-related care information, please visit PPMD’s Care for Lung Muscles section.