Study objectives: We sought to improve speech in tracheostomized individuals receiving positive-pressure ventilation. Such individuals often speak with short phrases, long pauses, and have problems with loudness and voice quality.
Subjects: We studied 15 adults with spinal cord injuries or neuromuscular diseases receiving long-term ventilation.
Interventions: The ventilator was adjusted using lengthened inspiratory time (Ti), positive end-expiratory pressure (PEEP), and combinations thereof.
Results: When Ti was lengthened (by 8 to 35% of the ventilator cycle), speaking time increased by 19% and pause time decreased by 12%. When PEEP was added (5 to 10 cm H2O), speaking time was 25% longer and obligatory pauses were 21% shorter. When lengthened Ti and PEEP were combined (with or without reduced tidal volume), their effects were additive, increasing speaking time by 55% and decreasing pause time by 36%. The combined intervention improved speech timing, loudness, voice quality, and articulation. Individual differences in subject response to the interventions were substantial in some cases. We also tested high PEEP (15 cm H2O) in three subjects and found speech to be essentially identical to that produced with a one-way valve.
Conclusions: These simple interventions markedly improve ventilator-supported speech and are safe, at least when used on a short-term basis. High PEEP is a safer alternative than a one-way valve.