Adverse effects
Of the three trials that reported how well techniques
were tolerated, two trials reported adverse events. The
adverse effects occurred immediately after the use of percussion
in both trials, resulting in a small but significant decrease
in FEV1 However, FEV1 returned to baseline after
20 minutes in one trial . The third trial reported that 15%
of participants experienced discomfort during use of PEP,
but it was not severe enough for them to stop treatment .
None of the trials reported any participan