I experienced the same phenomena, but felt that it was more to getting used to the treatment than "clearing out." After thinking about why this was happening, and what it meant, I emailed the primary investigator of the UNC Chapel Hill study, and asked if increasing the % of saline inhaled would produce more results (ie. sputum production).
This was what I asked him:
"How was 7 percent saline determined to be the desired concentration? After using 7 percent for the last two months, I feel that I have gotten used to the treatment, and don't find it nearly as "harsh" to inhale as I once did. I also find that 7 percent isn't bringing up stuff as easily - I can still "feel" the junk down there, its just harder to clear than it was at first.
I am writing because I have been tempted to try inhaling 10 percent saline, hoping to get more of a clearing effect, and find that I indeed do. I recognize that there may be legitimate reasons behind not using 10 percent on a regular basis, particularly the creation of a severe inflammatory response that might result in less toleration of saline - even at lower concentrations. However, if 7 percent was selected because it represents a balance between the positive effect of the HS and what CF patients (across the spectrum of the disease) could be expected to tolerate and comply with, then that's different."
This was his reply:
"Regarding the concentration that was studied, 7% was a compromise between a dose that was most effective and what is well tolerated (in short term studies of mucociliary clearance - where 0.9%, 3%, 7%, and 12% were tested - 7% and 12% were similar, and better than 0.9 and 3%, but 12% wasn't well tolerated). Therefore, if concentrations higher than 7% are well tolerated in an individual, we have often gone up to 10% with further benefit (if you tolerate 7% easily, you probably will tolerate 10%, but obviously should do this in conjunction with your CF doctor). Your instinct to increase to 10% is probably a good one, therefore..."
After talking to my Dr., I began inhaling 4ml of 10% twice a day.
It does indeed make the saline treatment feel like its doing more for me.
It also costs me half as much, because CFF Pharmacy considers the 7% "kit" two prescriptions (which is ridiculous, but that's another topic).
Anyway, if you feel comfortable with 7%, I would recommend trying 10% to see if you feel like its doing more for you.
Chris
26 w/CF
