IPPV and incentive spirometry were consistent with bestpractice
recommendations [5]. As for postural drainage and
percussion, although three of the trials included
these two techniques and described dosages in full, there were
differences between the trials and inconsistencies with bestpractice
guidelines. The duration of treatment for postural
drainage across the three trials varied from 15 to 20 minutes,
while the degree of tilt, when reported, was consistent at
12◦ across two trials. This differs from the recommended
15 to 20◦ , and thus may have contributed to
the technique being ineffective. On the other hand, continuous
percussion was performed between 5 and 15 minutes
. This length of time is longer than the recommended
time of 1–2 minutes per burst in one position , and
thus may have resulted in the decrease in FEV1 during intervention.
Therefore, it is possible that a lack of the quality of
intervention in the trials evaluating postural drainage and percussion
may have influenced the findings of a lack of effect.
Future trials should ensure that the dosages and positions of
interventions are based on best-practice guidelines.
The other limitation to this reviewis the presence of a large
variety of outcome measures. Thirty-nine different outcome
measures were used across the 13 trials, resulting in clinical
heterogeneity; therefore, it was not possible to synthesise the
results quantitatively and complete a meta-analysis.