Summary of main results
We have found no evidence to support the use of incentive spirometry
(IS) in the prevention of pulmonary complications after upper
abdominal surgery. We set out to identify the best clinical evidence
available to answer our question, and performed an extensive
search with careful quality assessment, but only limited conclusions
can be drawn from the trials that were included. This review
has been limited mainly by the low quality of the trials available
for inclusion. The methodological descriptions reported inadequate
methods of randomization and allocation concealment,
and there were limitations to the blinding. Only two studies (Hall
1991; Hall 1996) showed adequate allocation concealment; the
other studies did not report adequate concealment. Further, the
majority of the included trials did not address the same outcomes
and for this reason the pooling of data was seldom possible. Some
included studies did not provide separate data for patients undergoing
upper abdominal surgery. This meant that their data could
not be used in themeta-analysis.The small number of trials and the
sometimes low methodological quality meant that our intended
sensitivity analyses were not possible. In particular, we would have
welcomed the opportunity to establish a possible difference between
trials where compliance with the prescribed therapy was
recorded and those trials where it was not. Although compliance
with treatment is not a standard methodological quality marker,
it is important in this context. There is a great deal of heterogeneity
amongst the studies in the different physiotherapy techniques
described, both in the IS groups and in the comparison groups.
The comparison groups may not strictly be control groups, and
some papers did not report what constituted standard therapy or
standard care. This variation is inherent in physiotherapy practice
andmay reflect the lack of a ’gold standard’ method. In some studies,
additional therapeutic procedures were applied to either the
IS or control group, or both, thus making it difficult to assess the
pure effect of the experimental intervention. The poor coverage
of the different devices also made our planned subgroup analyses
impossible.
The age of some of the devices, and the trials evaluating them, is
also relevant. A number of older studies are of poormethodological
quality and might also describe practice which is less applicable to
modern physiotherapy. For instance, we have included trials of the
Bartlett-Edwards spirometer from the 1970s (Craven 1974; Dohi
1978; Lyager 1979) and 1980s (Celli 1984; Jung 1980;O’Connor
1988; Ricksten 1986; Schwieger 1986; Stock 1985). Clinicians
should consider this point in applying the findings to their clinical
practice as the Bartlett-Edwards spirometer is an obsolete technique.
The need to compare disposable or cleanable ISs is strongly
advised.
We had hoped to be able to comment on the effective use of
resources. However, both the cost of any intervention and the
benefit it offers must be taken into account. As we have been
unable to make a clear statement on effectiveness there can be no
further consideration of overall cost-effectiveness.
Further well-designed research studies are necessary, with longterm
follow up.