Received: 6 September 2019
Accepted: 29 December 2019
First Online: 13 January 2020
Ethics approval and consent to participate
: The study was conducted according to the ethical guidelines of the 1975 Declaration of Helsinki (6th revision, 2008). The study protocol was approved by the ethics committee of the Landesärztekammer Rhineland-Palatine (Nr. 837.232.17 ). Written informed consent was obtained from every participant.
: Authors have agreed to submit it in its current form for consideration for publication in the journal.
: The authors declare that they have no competing interests.