The Influence of Age on Bispectral Index Associated With Propofol-induced Sedation
试验速览
- 阶段
- 3 期
- 状态
- 已完成
- 入组人数
- 70
- 试验地点
- 1
- 主要终点
- Bispectral Index (BIS) values
研究概览
简要总结
The bispectral index (BIS) is commonly used in anesthesia to evaluate the depth of sedation. Numerous studies in adults have shown good correlation between bispectral index values and depth of sedation regardless of the hypnotic drug used. Requirements of intravenous and inhalational hypnotic agents to suppress consciousness decrease with age. A study showed that the loss of consciousness (LOC) was obtained with lower concentrations of sevoflurane in elderly than in young adults, but at identical BIS values, so that BIS would predict depth of sedation better than drug monitoring. This result incited the use of bispectral index monitoring to overcome the significant pharmacological variability, especially in elderly. Nevertheless, another research with a comparable methodology during propofol-induced anaesthesia provided higher BIS values at LOC in elderly compared to younger patients. In these two trials, LOC was defined differently: either by absence of verbal response corresponding to loss of eyelash reflex (LOER) or by absence of response to prodding [(OAA/S) <2)]. Otherwise electromyographic activity (EMG) was not taken in account. As high EMG level (greater than 50 decibels) could create subtle artifact signal pollution without necessarily being displayed as artifacts, this would be misinterpreted by the BIS algorithm as EEG activity and assigned a spuriously increased BIS value.
The main objective of our study was to specifically evaluate BIS values according to age during propofol-induced sedation. LOC was measured by obtaining an OAA/S score <2 (OAA/S2), or a deeper sedation criterion: loss of eyelash reflex (LOER). The secondary objective was to specify the influence of EMG on the displayed BIS values and its age-related modifications.
详细描述
The study was approved by the ethics committee of the Saint-Etienne University Hospital. After informed consent, 70 patients over 18 years of age, ASA I to III, scheduled to undergo orthopaedic surgery under general anaesthesia were included.
Exclusion criteria were the presence of heart, respiratory, hepatic or renal failure; a psychiatric or neurological pathology, severe depression or dementia; gastro-oesophageal reflux, hiatal hernia; drug addiction or chronic alcoholism; obesity with a body mass index greater than 30.
The patients received no pre-medication. After insertion of a venous line, a Ringer's Lactate perfusion was initiated. Oxygen therapy at a rate of 4 litres per minute was administered in spontaneous ventilation. In case of hypoventilation (saturation (SaO2) <95% and/or end-tidal carbon dioxide concentration (EtCO2) >42 mmHg, manual ventilation with a mask at 10 l/min of O2 was administered.
Propofol was administered using a commercially available target-controlled infusion with an incorporated pharmacokinetic model developed by Schnider (Base Primea , Fresenius-Kabi, Brezins, FRANCE). The initial effect-site target concentration of propofol (0.5 μg/ml) was incremented by 0.5 μg/ml every 5 minutes to ensure equilibration between plasma concentration and effect site, until LOER. From the beginning of infusion until LOER patients received no other agent besides propofol for the duration of the trial.
LOC was evaluated by an independent observer using two different criteria: OAA/S score <2 (OAA/S2) corresponding to the absence of response to moderate prodding and LOER.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Screening
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •patients over 18 years
- •ASA I to III
- •scheduled to undergo orthopaedic surgery under general anaesthesia
排除标准
- •presence of heart, respiratory, hepatic or renal failure
- •psychiatric or neurological pathology
- •severe depression or dementia
- •gastro-oesophageal reflux
- •hiatal hernia
- •drug addiction or chronic alcoholism
- •obesity with a body mass index greater than 30
研究组 & 干预措施
propofol induced sedation
Propofol was administered using a commercially available target-controlled infusion with an incorporated pharmacokinetic model developed by Schnider (Base Primea , Fresenius-Kabi, Brezins, FRANCE)12. The initial effect-site target concentration of propofol (0.5 μg/ml) was incremented by 0.5 μg/ml every 5 minutes to ensure equilibration between plasma concentration and effect site, until loss of eyelash reflex. From the beginning of infusion until LOER patients received no other agent besides propofol for the duration of the trial.
干预措施: Propofol induced sedation (Drug)
结局指标
主要结局
Bispectral Index (BIS) values
时间窗: loss of consciousness (LOC), approximatively 20 to 30 minutes after the beginning of anesthesia
Electroencephalographic activity was monitored by BIS Quatro XP platform® electrodes and a BIS VISTA™ 1.01 monitor (Aspect medical system, MA, USA). The impedance of each electrode was kept below 5 kΩ. The sensor were reapplied if the quality of the detected signal was not suitable to provide a reliable BIS score i.e a signal quality index (SQI) better than 50%. The trace was displayed in real time and calculated data (BIS) were recorded continuously using the archiving function integrated in the monitor. A 30 second smoothing period was set to minimize the variability and sensitivity of artifacts. BIS values were validated throughout the trial by SQI values greater than 90.
次要结局
- the EMG component of the bispectral index value(loss of consciousness approximatively 20 to 30 minutes after the beginning of anesthesia)