Ventilator-Assisted Living©

Spring 1999, Vol. 13, No. 1

(continued)

Let's Hear It for Free Speech!

Sharon Davids, RRT, Greenbriar Rehabilitation

As a respiratory therapist, I help ventilator users with tracheostomies to speak with the aid of the Passy-Muir Valve (PMV) which enables their speech to be free and uninterrupted.

photo of several Passy-Muir valvesHow does the PMV work? It is a one-way valve that enables air to enter via the trach tube and exit around the outside of the trach tube (cuffless or deflated). The valve may be attached directly to the trach tube, or on the side of an inline suctioning system or swivel adapter. Four models of valves are available, but they all function on the same positive closure principle. The white valve is the original PMV, and more commonly used by non-ventilator users. The clear and purple valves are low-profile, lighter weight, and have a tether which can be attached to the trach tie in case of detachment from the trach tube. They can be used inline with a ventilator using nondisposable, flexible rubber tubing. The aqua valve is designed to easily attach to disposable ventilator tubing and works best inline with a ventilator.

What is the importance of allowing exhaled air to exit around the outside of the trach tube? There are several reasons, but the most important is that ALL of the exhaled air (unless there is leakage around the stoma) is able to pass through the vocal cords to enable speech. And not just any speech, but the speech you would have if you did not have a trach. If you have seen Christopher Reeve on television, you may have noticed that he was speaking while using his ventilator. This is an example of "leak" speech: some of his exhaled air returns to the ventilator, while some of it passes through his vocal cords. He must wait for a breath from the ventilator before he can talk. You may also have noticed that sometimes his voice trails off at the end of his sentences, and he must pause and wait for a breath from the ventilator before trying to talk again. When my patients use a PMV, these leak speech problems do not occur.

There are some research-validated physiologic advantages of using a PMV that I see every day. Many of them are due to positive closure, a patented feature of the PMV which makes it unique among the other speaking valves on the market. This means that a PMV will open easily during inspiration, but it will automatically close at the end of inspiration, causing all of the air to be exhaled past the vocal cords and through the nose and mouth. Thus, NO air is able to leak upon exhalation, creating a Diagram showing placement of Passy-Muir valve.normal respiratory system, benefiting many actions such as swallowing and coughing.

In swallowing with a PMV, exhaled air is no longer leaking out of the trach tube, but instead is exiting normally via the upper airway. This restores the pressure needed in the pharynx (throat) to facilitate a better, faster, and stronger swallow. And because airflow has been restored in the upper airway, sensation can be increased so that you can feel if something is stuck in your throat, allowing you to cough to clear the throat and protect the airway.

By creating a resistance because the trach is not leaking air on exhalation, there is more force to produce a stronger cough, permitting secretions to be coughed out of the mouth instead of the trach. When secretions are coughed up, they go around the outside of the trach tube, rather than inside, as a column of air is trapped in the trach tube when the PMV is in place. To allow for adequate space around the outside of the trach tube for comfortable exhalation, you may need a smaller size trach tube.

Oxygen saturation actually increases, as physiologic pressures are restored that allow the alveoli (tiny air sacs in the lungs) to remain inflated at their normal pressure. Again, thanks to no leakage.

With air moving through the upper airway again, senses of smell and taste are improved. A bowel movement is easier, because you can push down harder with your diaphragm.

Decannulation and weaning are faster with a PMV, due to its ability to restore a more normal physiology to the airway.

A physician's order is necessary to obtain a PMV, and initial placement should be by a qualified health professional, such as a certified or registered respiratory therapist. Changes may need to be made to the ventilator settings to compensate for leaks, usually by increasing the tidal volume and flow rate so that the peak inspiratory pressure is similar to what it was prior to deflating the cuff and placing the PMV. The pressure alarms may then have to be readjusted, especially the low pressure alarm to ensure alarming during a disconnect.

Verbal communication has psychological benefits as well, by enhancing our ability to direct our lives and to enable more active social participation. The use of the PMV is easier and more efficient than anything else I have ever used, and it has improved the quality of my patients' lives far better than any other device for communication.

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