Dear scaredwifetx,
Your husband’s reluctance to use his trilogy may be due to denial or depression. It may also be related to the use of an uncomfortable mask. These issues need to be explored in order to determine the root cause of his refusal to use his trilogy. Discussion, psychological counseling and/or medication may help deal with this issue. He definitely needs to use his trilogy every night. The main issue with the use of noninvasive ventilation is that it allows the diaphragm to rest and recuperate. There is good evidence that your husband survival time will be increased because a rested diaphragm will deteriorate at a slower rate. It is no wonder that your husband does not feel short of breath with an FVC 47% while breathing at rest, since he has enough vital capacity to still allow him to breathe in an adequate volume of air while sitting at rest. I think it would be a good idea to buy an oximeter (less than $50 on line) to measure your husband’s oxygen saturation level. If it remains at or above 95% and does not feel short of breath then he is getting enough air. Nevertheless, his diaphragm must be working awfully hard to accomplish this, and he would be still benefit from using his trilogy as much as he can tolerate during the day. If his oxygen saturation level is less than 95, then he absolutely needs to use his trilogy regularly during the day in order to raise the level to or above 95% if he wishes to maximize his survival time.
I think it would be a good idea to have a long conversation with Steve regarding survival time and the use of his trilogy and find out his reasons for not using it. If he is in denial or depressed than he needs treatment for that. If it's due to discomfort from the mask, then ask the respiratory therapist to bring in a number of samples until Steve can find a mask that is tolerated.
It seems that in ALS all things are related. As the FVC falls below 50%, the diaphragm begins to move up in the chest and as a consequence so will the stomach, which lies just beneath the diaphragm. When this happens, the stomach may move so high that it moves into the rib cage, which will make it very difficult or impossible to place a PEG. Therefore, if Steve wants a PEG, this is the time to do it. Unnecessary delays risk complications or limit your options.
Best wishes
Eliot