TUCSON—Communication is difficult for patients with tracheostomies who are receiving positive-pressure ventilation. If they can talk at all, their speech is usually characterized by short phrases, long pauses, and variable loudness. A new study shows that significant improvements in these parameters can be achieved by adjusting the ventilator to lengthen the inspiratory time (TI), include positive end-expiratory pressure (PEEP), or both.[1]

Jeannette D. Hoit, PhD, from the Department of Speech and Hearing Sciences at the University of Arizona, said that the ventilator adjustments she and her colleagues tested provide “a safer and more conservative way to improve speech in invasively ventilated patients compared with the more commonly used one-way valve.”

The 15 study subjects had either spinal cord injury or neuromuscular disease and were receiving long-term ventilation. After being assigned individualized TI and PEEP levels, they were asked to read a paragraph aloud and then rate their speech and breathing. Speech samples were recorded with and without the interventions and analyzed by certified speech-language pathologists.

Speech improvements were seen in 12 of the 15 subjects with one or more of the interventions. Most of the subjects and listeners rated the speech as sounding better than usual, and most of the subjects rated their breathing as feeling better than usual. (Of the three patients who did not benefit from the ventilator modifications, two exhibited laryngeal dysfunction and one had a substantial stoma leak.)

In the six who had their TI lengthened by 8% to 35%, speaking time increased by 19%. This improvement was attributed largely to the increase in the number of syllables produced per inspiration, which rose by 58%. TI lengthening also led to a 12% decrease in pause time, although the finding was not statistically significant.

In eight subjects who were not using a one-way valve, low levels of PEEP were administered (5 to 10 cm of H2O). For these individuals, speaking time and the number of syllables produced per breath both increased by 25%, and pause time decreased by 21%.

Using both interventions simultaneously produced additive benefits. In the six subjects who had TI as well as PEEP adjustments, speaking time increased by 55% and pause time decreased by 36%. Syllables per breath rose by 61%.

Dr. Hoit said that the advantages of making one or both of the ventilator changes should be weighed against their potential disadvantages. Lengthened TI, for example, “may cause hypoventilation if too much of the ventilator-delivered tidal volume is ‘bled off’ for speech production,” she explained. With PEEP, theoretical risks include barotrauma and reduced cardiac output.

Once the optimal ventilator adjustments are determined, should they be left in place? “There are patients who benefit from having the ventilator adjusted permanently, at least for daytime use,” Dr. Hoit said. Others may be “better off using their ‘speech settings’ for only the short periods in which they expect to be doing a lot of talking.”

—Verna L. Schwartz, MS

Reference
1. Hoit JD, Banzett RB, Lohmeier HL, et al. Clinical ventilator adjustments that improve speech. Chest. 2003;124:1512-1521.

Return to table of contents