The Impact of Bispectral Index Monitoring on Outcomes in Spinal Cord Stimulation for Chronic Disorders of Consciousness.

Objective: To observe whether maintaining the appropriate depth of anesthesia with Bispectral Index (BIS) can improve the prognosis of Spinal Cord stimulation (SCS) implantation in patients with chronic Disorders of consciousness (DoC).

Methods: 103 patients with DoC undergoing SCS implantation were reviewed, and 83 patients with DoC were included according to the standard of inclusion and exclusion Criteria. Patients were divided into a BIS group (n =45) and a non-BIS group (n =38) according to whether BIS monitoring was used during the operation. The depth of anesthesia in the BIS group was maintained between 40-60. The anesthesiologist adjusted the depth of anesthesia in the non-BIS group according to clinical experience. Relevant information such as disease course, cause, anesthesia time, and operation time were collected. Preoperative CRS-R_{(preoperative)} score, postoperative CRS-R_(24h), and postoperative CRS-R_(3m) changes were collected.

Results: The CRS-R(3m) score in the BIS group was higher than that in the non-BIS group _{(preoperative)}, and the difference was statistically significant (P < 0.05). In CRS-R _(24h), the BIS group was higher than the non-BIS group, and the difference was statistically significant (X²=8.787, P =0.004). The improvement of consciousness was included in the multivariate Logistic regression analysis model, and it was found that the thalamus was an independent factor affecting the improvement of consciousness (P < 0.05). During follow-up, 1 patient in the BIS group had a decrease in consciousness from MCS^- to VS/ UWS and 2 patients in the non-BIS group died during follow-up.

Conclusion: Patients can be benefit in hearing in CRS-R _(24h). We recommend the use of BIS to monitor the depth of anesthesia in patients with DoC to improve patient outcomes.