I know, you see Passy muir. What is it? I work in the medical field and will explain the use of the passy muir. The PMV (Passy muir valve) was invented by David Muir who has since passed away. He had MS at the age of five and progressively got worse until he became a quadriplegic. He was studying biochemical engineering at age 23 in college. While in college, he had a respiratory arrest and then was ventilator dependent. He began to focus on a way to speak. The respiratory arrest/vent dependent took away so much but he wanted to be able to speak again. He developed the passy muir. You wouldn't think such a small valve could give a person/child/baby the gift of speaking. It is truly amazing! And David can be remembered as the person making a great impact on their lives. The passy muir has different sizes to accomodate the size of tracheostomy tube used by the patient. The valve is plastic with a screen inside to allow the patient to talk and wean from the ventilator. How does the Passy work? As the patient inhales, the valve opens and lets air into the trach tube and lungs. At the end of inhalation, the valve closes and stays closed during exhalation. Exhaled air goes out the mouth/nose. The whole process is descibed in your phamplets received with the passy muir. The booklet also talks about trouble shooting, cleaning the valve, tracheostomies, etc... This medical device is covered by most insurance companies and medicaid. This device makes a world of difference to those on a ventilator. The patient, once determined to qualify for a PMV, can gradually work toward being off the ventilator for long periods of time. This in itself makes this device a godsend in my opinion. There is nothing like being confined to a ventilator in order to breathe. The PMV is so simple to use and the best intervention from one, David Muir.