Retraction Note: BMC Anesthesiol (2018) 18:145

https://doi.org/10.1186/s12871-018-0608-3

The authors have retracted this article [1] because they have recently found that the clinical results for the dosage of postoperative opioids in some patients were inconsistent with the results presented. In light of these findings, the authors no longer have confidence in the accuracy of the reported data and the conclusions of the article and wish to redesign the programme of postoperative analgesia and re-analyse their work. The authors would like to apologise for any inconvenience. All authors agree to this retraction.