Retraction Note: Journal of Clinical Monitoring and Computing (2019) 34:303–310

https://doi.org/10.1007/s10877-019-00306-y

The Editor in Chief has retracted this article. After an investigation by Juntendo University Hospital it was discovered that the authors made changes to the study protocol without obtaining ethical approval. Osamu Kudoh has stated on behalf of all co-authors that they do not agree to this retraction.