Kalgudi Pramod, Bharadwaj Suparna, Chakrabarti Dhritiman, Bhadrinarayan V, Uppar Alok M, Prasad Chandrajit
Department of Anaesthesia, Institute of Neurosciences, M S Ramaiah Medical College, Bengaluru, Karnataka, India.
Department of Neuroanaesthesia and Neurocritical Care, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India.
Neurol India. 2024 Nov 1;72(6):1179-1185. doi: 10.4103/neurol-india.Neurol-India-D-23-00012. Epub 2024 Dec 17.
The electrophysiological process of emergence from general anesthesia (GA) commences from deeper structures of the brain rather than the cortex. The phylogenetically old parts of the brain (hippocampus) are the first to recover during emergence. Study objectives were to evaluate and predict the effect of preoperative hippocampal volume (HV) measured using MRI with emergence from GA and delayed extubation in patients undergoing elective neurosurgical procedures.
Patients aged 18-65 years of age scheduled for elective neurosurgical procedures under GA with GCS = 15 were recruited into the prospective cohort. Those who underwent excision of the hippocampus, amygdala, and temporal lobe pathology were excluded. Bilateral HVs and total brain volume were measured preoperatively using MRI brain. GA was induced by thiopentone, fentanyl, and vecuronium and maintained with sevoflurane. At the end of the surgery, sevoflurane was turned off, and a fresh gas flow of 6 L min-1 oxygen was set, allowing patients to wake up by "no contact technique." Time elapsed from turning off sevoflurane till the onset of different phases of emergence was measured. The patterns of emergence were assessed using GCS and Riker Sedation-Agitation Scale.
The complete data of 125 patients of 1192 screened for recruitment were analyzed. The median time for extubation was 13 minutes (IQR 9-16). The average bilateral standardized HV had a statistically significant negative correlation with the time to extubation (r = -0.185; P = 0.039). Average of bilateral standardized HV <2097 mm3 predicts delayed extubation with a specificity: 70.7%, sensitivity: 51.2% and AUC: 0.672, CI 0.524-0.724. Standardized dominant HV <1925 mm3 also predicts delayed extubation with specificity: 78%, sensitivity: 46.4% and AUC: 0.635, CI 0.533-0.738.
Neurosurgical patients with larger average HV might lead to early extubation, vocalization, and faster gaining of orientation after GA.
全身麻醉（GA）苏醒的电生理过程始于大脑深层结构而非皮层。大脑中进化上较古老的部分（海马体）在苏醒过程中最先恢复。研究目的是评估和预测择期神经外科手术患者术前通过磁共振成像（MRI）测量的海马体体积（HV）对GA苏醒及拔管延迟的影响。
将计划在GA下进行择期神经外科手术且格拉斯哥昏迷量表（GCS）=15分的18 - 65岁患者纳入前瞻性队列研究。排除那些接受海马体、杏仁核及颞叶病变切除术的患者。术前通过脑部MRI测量双侧HV及全脑体积。GA诱导采用硫喷妥钠、芬太尼和维库溴铵，并以七氟醚维持麻醉。手术结束时，关闭七氟醚，并设置6 L/min的新鲜氧气流，采用“无接触技术”让患者苏醒。测量从关闭七氟醚到出现不同苏醒阶段所经过的时间。使用GCS和Riker镇静 - 躁动量表评估苏醒模式。
对筛选纳入的1192例患者中的125例完整数据进行了分析。拔管的中位时间为13分钟（四分位间距9 - 16分钟）。平均双侧标准化HV与拔管时间存在统计学显著负相关（r = -0.185；P = 0.039）。平均双侧标准化HV<2097 mm³预测拔管延迟的特异性为70.7%，敏感性为51.2%，曲线下面积（AUC）为0.672，可信区间为0.524 - 0.724。标准化优势侧HV<1925 mm³预测拔管延迟的特异性为78%，敏感性为46.4%，AUC为0.635，可信区间为0.533 - 0.738。
平均HV较大的神经外科手术患者在GA后可能导致早期拔管、发声及更快恢复定向能力。
