Author Reply

Sir,

Thank you for your comments regarding our article “Monitoring the depth of anesthesia using the new modified entropy sensors during supratentorial craniotomy: our experience”.[1] We completely agree the authors’ comments regarding that our study has major limitations and the study results should be interpreted with caution.

We completely agree with the comment regarding the placement electrodes. Electrode #1 is indeed the reference electrode and should be placed in the between the eyebrows. We apologize for the error in the figure 2 in our manuscript. Electrode 1 should be in between the eyebrows and the electrode 2 should be at the temporal location.

The aim of our study was to address the common problems with depth of anesthesia monitors in neurosurgical patients especially supratentorial craniotomies and to determine the feasibility of using the new GE entropy sensors in monitoring depth of anesthesia in these patients. Our study was a simple proof of concept observational study to show that it is feasible to monitor depth of anesthesia using a modified electrode placement with the new entropy sensors. These new sensors offer flexibility in terms of placement in modified positions.

We did not do quantitative statistical analysis to show reliability and correlation with other depth of anesthesia indices (end-tidal anesthetic concentration or hemodynamic parameters) as this is not the primary objective of this study. Hence, we did not present the hemodynamic data in the manuscript, as this information did not provide any additional information to the manuscript. We did address some of these issues in the manuscript as the limitations of the study. There is a need for prospective study to determine the reliability of these sensors to monitor depth of anesthesia in the modified electrode placements.

No conflict of interest has been declared by the author(s).

• REFERENCE

• 1 Sharma R, Manninen P, Venkatraghavan L. Monitoring the depth of anaesthesia using the new modified entropy sensors during supratentorial craniotomy: Our experience. J Neuroanaesthesiol Crit Care 2015; 2: 28-32