Text and Data Mining valid from 2018-10-25
Received: 16 August 2018
Accepted: 30 September 2018
First Online: 25 October 2018
Ethics approval and consent to participate
: The study protocol was approved by the ethical committee of the anesthesia department and registered on 14/2/2015. Written consents was not obtained from the patients, this was waived by the ethical committee as this was an observational study.
: Not applicable.
: “The authors declare that they have no competing interests”.
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