Changes of EEG induced by low-dose propofol anesthesia during spinal cord electrostimulation implantation in vegetative state patients
Authors: Qin Xuewei , Chen Xuanling , Zhao Xin , Wang Bo , Tang Yi , Yao Lan , Guo Xiangyang , Liang Zhenhu , He Jianghong 
Published: March 2023

Abstract
Objective: To compare the use of low-dose propofol anesthesia induction in general anesthesia between the vegetative state (VS) group and the non-vegetative state (NVS) group of non-cranial surgery, to observe the characteristics of EEG changes and whether there is outbreak inhibition, and to find a rational drug use scheme for surgical anesthesia in VS patients.
Methods: From February to March 2022, 3 patients with vegetative state (VS group:2 cases with craniocerebral trauma VS and 1 case with ischemic hypoxia VS) and 3 patients with non-vegetative state (NVS group) were admitted to the Department of Neurosurgery of Peking University International Hospital from February to March 2022. In both groups, 0.5mg/kg propofol was used for anesthesia induction, and BIS changes were observed within 5 minutes after administration. The original EEG and perioperative EEG of the two groups of patients were collected and restored by BIS, and the original EEG was analyzed and processed with the help of the EEGLAB toolbox in the MATLAB software, and the spectral and power spectra of the two groups were obtained to analyze the characteristics of EEG changes.
Results: There was no significant difference in preoperative general data between the two groups (P>0.05). The decrease in BIS in the VS group using 0.5mg/kg propofol induction for 1 min, 2 min, 3 min, 4 min and 5 min was significantly higher than that in the non-vegetative state group of non-cranial surgery (P <0.05）。 The spectrum analysis showed that the energy protrusion band of the α band of about 10Hz in the EEG of the NVS group was prominent, and the high-frequency energy was reduced. Patients with craniocerebral trauma VS have reduced high-frequency energy and the main energy is concentrated below 10Hz; Patients with ischemic hypoxia VS have higher energy in the 10 to 20 Hz band. On the power spectrum, it can be seen that the EEG energy of the NVS group is weakened 5 min after anesthesia induction compared with the first 5 min induction of EEG, mainly concentrated in the small wave peak, that is, the α band peak after 10Hz. Patients with craniocerebral trauma VS had reduced energy after anesthesia induction, but no α band peaks appeared; In patients with ischemic hypoxia VS, there was no significant change in the energy of the lower frequency band after anesthesia induction, and the high frequency energy was significantly weakened, and a significant α band peak was observed, which appeared after 10Hz. In the VS group after spinal cord stimulation surgery 3 months after surgery, the CRS-R score of one patient with head injury VS increased by 1 point, and the CRS score of the remaining 2 patients did not change.
Conclusion: After induction of low-dose propofol anesthesia, there are obvious differences in EEG changes in VS patients compared with normal patients, and there are also differences in EEG changes in different types of VS patients, but there is no explosive inhibition. The reason may be that the damaged brain has a better protective response to itself, which may also be the basis of wakefulness-promoting treatment. At the same time, the use of low-dose propofol for general anesthesia did not show adverse effects on the awakening treatment of VS patients under the premise of meeting the requirements of surgical procedures.