Document is current

Article History

Received: 12 December 2017

Accepted: 15 January 2018

First Online: 19 January 2018

Ethics approval and consent to participate

: This retrospective cohort study only used clinical data that were already collected for administrative purposes; formal patient consent was considered not necessary and ethics approval was waived, and this study was registered with the Royal Perth Hospital Clinical Safety and Quality Unit (No: 22233) with an intention for peer-review publication.

: Consent for publication of non-identifiable data was waived by the Clinical Safety and Quality Unit of Royal Perth Hospital.

: The authors declare that they have no competing interests.

: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.