Reason for withdrawal from publication
This review has been withdrawn because it does it does not include recent evidence and does not reflect up‐to‐date Cochrane methodological standards.
The editorial group responsible for this previously published document have withdrawn it from publication.
History
Protocol first published: Issue 3, 2011 Review first published: Issue 1, 2012
Sources of support
Internal sources
Respiratory Medicine Unit, The Queen Elizabeth Hospital, Australia
External sources
No sources of support provided
Withdrawn from publication for reasons stated in the review