Vol. 17 Issue 12
Speaking Valve Benefits
Simple Interventions Markedly Improve Speech
Therapists who have seen them know a speaking valve is basically a plastic attachment with a one-way valve inside that fits onto the end of a tracheostomy tube. The valve opens during inspiration and closes during expiration, diverting air up through the voice box, throat and mouth/nose, facilitating speech under proper training by a speech pathologist.
Bias closed valves are normally closed. They open with inspiration and close as the inspiratory cycle ends. Bias open valves open and close with forceful expiration.
Speaking valves require a deflated cuff, may require oxygen through both upper and lower airway and are best used with cuffless, fenestrated or tracheal buttons, according to on-line health information from the University of Louisiana at Lafayette.
Benefits of speaking valves vary from patient to patient but may include a louder voice, clearer speech, normal passage of air through the throat and mouth, improved ability to smell and taste, reduced secretions, improved protection of the airway during feeding and swallowing, easier development of babbling in young babies (essential to cognitive development) and more efficient speech by older children, according to the Institute of Child Health, London, England.
Contraindications include use with Bivona Fome Cuff tubes, or if patients have tracheal edema or stenosis, end-stage pulmonary disease, severe aspiration, copious secretions, anarthria or severe dysarthria.
In 1999, three researchers analyzed certain aerodynamic properties of six commercially available one-way speaking valves: three designed for non-ventilator-dependent patients and three for ventilator-dependent patients.
They first tested for airflow resistance during steady-state flow testing and concluded that all six exhibited similar resistance characteristics, except for relatively minor differences at low flow rates.1
Researchers then tested the valves for air loss, using themselves as subjects. They simulated tracheostomy speech production by inspiring through a duckbill-like mouthpiece connected to a valve and a pneumotachograph. A nose clip occluded their nostrils to force inspiration through the valve. Then they intoned the syllable "pa" five times on continuous exhalation.
Using this methodology, they found that bias open valves consistently exhibited air loss during speech expiration when the valves should have been closed.
However, since they did not evaluate how actual trach patients would respond to this air loss relative to airway pressures, "we make no recommendations relative to the advantages of any specific one-way valve" for trach patients, they wrote.
In 2003, CHEST published a study of 15 adult ventilator patients with spinal cord injuries or neuromuscular diseases. Researchers in that study found that speech was improved not by valves but by lengthening ventilator inspiratory time and using positive end-expiratory pressure. "These simple interventions markedly improve ventilator-supported speech and are safe, at least when used on a short-term basis," they concluded. "High PEEP is a safer alternative than a one-way valve."2
Meanwhile, Michael Rutter, MD, a pediatric otolaryngologist at Children's Hospital Medical Center in Cincinnati has noted that many trach patients cannot use a speaking valve due to high subglottal pressure on expiration. Patients with subglottal stenosis, suprastomal collapse or too large a trach tube "are limited in their ability to exhale with a speaking valve in place," he noted on his Web site. "This results in a feeling of suffocation and raised intrathoracic pressure which can lead to valve displacement, compromised venous return and pulmonary hypertension."
Rutter et al. are testing patients with existing valves they have modified to "allow an appropriate amount of air leak from the trach tube to facilitate phonation through controlled, patient-dependent expiration," according to the Web site. "This markedly reduces intolerance caused by elevated intrathoracic pressure and will render the device universally applicable."
Rutter is currently pursuing a patent and seeking a manufacturer for the modified valve.
1. Zajac D, Fornataro-Clerici L, Roop T, et al. Aerodynamic characteristics of tracheostomy speaking valves: an updated report. Journal of Speech, Language and Hearing Research. (1999;42:92-100).
2. Hoit J, Banzett R, Lohmeier H, et al. Clinical ventilator adjustments that improve speech. Chest. (2003;124:1512-1521).