CJ,
We were first set up with a ResMed VPAP III, but have had so much trouble with the company we got it through that I requested that our ALS clinic rewrite the order and start all over with another company in our town. (I wrote all about it in my thread "Major BiPAP Woes" in case you didn't see it).
I read posts on this forum to find out what others were using and Al mentioned the Synchrony s/t by Respironics. I googled Respironics and read about the Synchrony line and it specifically mentions that ALS and neuromuscular patients may benefit from the Synchrony BiPAP line. The other Respironics BiPAP models didn't mention using with ALS and NMD patients. I am therefore specifying that we be issued a Respironics Synchrony s/t from the new company.
About s or s/t (spontaneous or spontaneous/timed) here's a quote from that article by Margie Petrakis RN that I gave a link to in the Caregiver forum in answer to the thread "possible start of bipap...have questions":
"The primary muscle of respiration is the diaphragm, a large muscle situated under the lungs. When the diaphragm contracts during inspiration, it moves downward and opens up the lungs, causing air to flow into the lungs. When the diaphragm relaxes, it moves upwards and pushes air, now containing carbon dioxide, back out of the lungs. If the diaphragm becomes weakened in ALS, it impairs the ability to take a deep breath. Other muscles involved in breathing are termed the “accessory muscles of respiration” and include the neck, chest, abdominal and back muscles...When the diaphragm is weak, these muscles end up doing some of the work of breathing to help keep oxygen and carbon dioxide levels normal... During deep sleep, the accessory muscles “turn off” and the only muscle working is the diaphragm...
The term “BiPAP”, is derived from “bi” meaning two (as in inhalation and exhalation) and PAP meaning positive airway pressure (positive pressure means air is pushed into the lungs). We prefer the term non-invasive positive pressure ventilation (NPPV) for this type of device since BiPAP is actually only the name of the original bi-level machine. There are other machines now available that do the same thing. NPPV designates two levels of positive pressure in the airways of the lungs. The machine applies a maximal amount of pressure directly into the airways when it senses that the patient is beginning inspiration (IPAP – inspiratory positive airway pressure). A second, smaller amount of pressure is exerted on expiration (EPAP- expiratory positive airway pressure). This lower amount holds the airways open and keeps the level of oxygen elevated to normal. When NPPV is set up on ALS patients, a “backup” breathing rate is usually set as well. If the breathing rate falls below a set level, the machine can automatically give additional breaths."
The part in red about a backup breathing rate being set as well means that the BiPAP machine must have not only the capability of giving spontaneous breaths, but also the capability of giving timed breaths. Therefore, the s/t would seem to be essential for ALS patients as the diaphragm weakens since during deep sleep the accessory muscles aren't working.
Hope this helps.
Jane