The Effect of Interscalene Brachial Plexus Block Combined With General Anesthesia on Burst Suppression Ratio in Patients Undergoing Shoulder Surgery
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 50
- 试验地点
- 2
- 主要终点
- Burst Suppression Ratio (BSR)
研究概览
简要总结
This prospective, randomized, double-blind clinical study aimed to investigate the effects of combining general anesthesia with an interscalene brachial plexus block (ISB) on burst suppression ratio (BSR) and electroencephalographic (EEG) activity in patients undergoing elective shoulder surgery. A total of 50 patients were allocated into two groups: those receiving general anesthesia with ISB (Group B) and those receiving general anesthesia alone (Group K). Intraoperative EEG recordings were obtained from frontal electrodes (Fp1, Fp2, F7, F8) using a SedLine® monitor. Power spectral analysis was conducted for delta, theta, alpha, and beta frequency bands, alongside assessment of Patient State Index (PSI) and BSR.
详细描述
This prospective, randomized, double-blind clinical trial was conducted to evaluate the neurophysiological effects of combining interscalene brachial plexus block (ISB) with general anesthesia in patients undergoing elective shoulder surgery. The primary objective was to investigate how ISB influences intraoperative burst suppression ratio (BSR) and EEG-derived brain activity, using quantitative parameters such as power spectral densities of frequency bands and Patient State Index (PSI).
A total of 50 ASA I-III patients scheduled for shoulder surgery were randomly assigned into two groups: Group B (general anesthesia + ISB) and Group K (general anesthesia only). Standardized general anesthesia was maintained with sevoflurane in both groups. EEG data were recorded continuously using a SedLine® monitor from frontal electrodes (Fp1, Fp2, F7, F8) during four perioperative phases. Spectral analysis was performed using Fast Fourier Transform (FFT) and Welch's method to quantify power in the delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), and beta (13-30 Hz) bands. BSR was calculated based on the duration of EEG suppression epochs, while PSI and SEF (Spectral Edge Frequency) were recorded continuously.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Screening
- 盲法
- Double (Participant, Outcomes Assessor)
盲法说明
The study was conducted in a double-blind design: both the patients and the professional responsible for EEG data analysis were blinded to group allocation.
入排标准
- 年龄范围
- 18 Years 至 65 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Patients classified as ASA Physical Status I-III
- •Aged between 18 and 65 years
- •Scheduled for elective shoulder surgery under general anesthesia, with or without interscalene brachial plexus block
排除标准
- •Advanced renal failure
- •Advanced hepatic failure
- •Body mass index (BMI) > 40 kg/m²
- •History of central nervous system disorders
- •Diagnosed psychiatric illness
- •History of substance abuse
- •Known allergy to any of the drugs used in the study
- •Refusal to participate or to provide informed consent
- •Termination Criteria:
- •Severe hypotension (mean arterial pressure < 50 mmHg despite treatment)
- •Severe bradycardia (heart rate < 40 bpm requiring intervention)
- •Profound hypoxia (SpO₂ < 90% despite oxygen support)
- •Drug-related allergic reactions
结局指标
主要结局
Burst Suppression Ratio (BSR)
时间窗: peroperative
Burst Suppression Ratio (BSR): The main quantitative indicator of deep cortical suppression, calculated as the percentage of time the EEG signal remained in a suppression state (defined as amplitude \<±10 μV for ≥0.5 seconds) during surgery. BSR was recorded continuously and analyzed across four perioperative phases (Phase 0-3).
Power Spectral Density (PSD) Analysis
时间窗: peroperative
The average spectral power (μV²) of EEG signals was analyzed for four conventional frequency bands-delta (0.5-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), and beta (13-30 Hz)-using FFT-based spectral analysis. These values were calculated from frontal electrodes (Fp1, Fp2, F7, F8), and comparisons were made between Group B (ISB group) and Group K (control group) at each phase.
Patient State Index (PSI)
时间窗: peroperative
The Patient State Index (PSI), a proprietary quantitative measure ranging from 0 to 100, is derived from multichannel electroencephalogram (EEG) signals using the SedLine® brain function monitoring system. Higher PSI values indicate lighter levels of anesthesia or increased cortical activity, whereas lower values correspond to deeper anesthetic states. In this study, PSI values were utilized to monitor the level of consciousness and cortical stability during the intraoperative period. Particular emphasis was placed on PSI trends observed during Phase 1 (following the administration of the interscalene block but prior to the induction of general anesthesia), in order to investigate any pre-anesthetic central nervous system effects attributable to the regional block.
次要结局
- Mean Arterial Pressure (MAP)(peroperative)
- Anesthetic and Analgesic Drug Consumption(peroperative)
- Postoperative Pain Scores(During PACU stay (up to 2 hours))
- Nursing Delirium Screening Scale (NUDESC)(During PACU stay (up to 2 hours))
- Heart Rate (HR)(peroperative)
- Oxygen Saturation (SpO₂)(peroperative)
研究者
Tugba KOK
MD
Bezmialem Vakif University