Vertebral canal haematoma and coagulopathy

information was not included in the Methods section of our article. In contrast, however, BIS was relatively low at 3 mg ml of TCI. Although the TCI system does not predict plasma propofol concentration completely, a BIS monitor can be used during general anaesthesia. Remifentanil, however, affects the EEG characteristics during propofol anaesthesia. Therefore, we also wanted to know how remifentanil affects BIS per se during propofol anaesthesia. Unexpectedly, our findings indicate the possibility that BIS does not reflect the actual plasma propofol concentration when co-administered with remifentanil. Thus, anaesthetic depth management using propofol TCI with remifentanil co-administration may be complicated, even when surgical stimulation is absent. Because remifentanil is used under surgical stimuli in a clinical setting, we think that further studies are necessary to clarify the effect of remifentanil on plasma propofol concentration or BIS during surgical stimulation. We cannot say whether presenting TCI is acceptable in scientific journals, but we believe that our findings are important for readers, especially those who use propofol TCI clinically.