Received: 16 October 2018
Accepted: 26 December 2018
First Online: 17 January 2019
Ethics approval and consent to participate
: Ethical Approval is obtained from the Regional ethics comity of Stockholm 2015/323–32. Informed consent to participate in the study was given by the participating patients.
: Not applicable.
: JvdL and PS are shareholders of the company that manufactures the mini-diffuser and JvdL is a member of the company board.
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