Preoperative Dexmedetomidine Reduces the EC50 of Propofol for Successful i-gelTM Insertion Without Muscle Relaxants
试验速览
- 阶段
- 4 期
- 状态
- 已完成
- 入组人数
- 37
- 试验地点
- 2
- 主要终点
- EC50 of propofol required for successful i-gel insertion
研究概览
简要总结
Dexmedetomidine is a useful anaesthetic adjuvant for general anaesthesia. In this prospective randomised study, we determined whether preoperative dexmedetomidine administration could reduce the half maximal effective concentration (EC50) of propofol for successful i-gelTM insertion without muscle relaxants.
详细描述
Propofol is a useful induction agent for LMA insertion without muscle relaxants because it profoundly inhibits pharyngeal and laryngeal reactivity. A previous report showed that the effect-site concentration of propofol for successful classic LMA insertion in 50% of adults (EC50) without muscle relaxants in healthy male patients was 8.72 (0.55) µg ml-1. The EC50 of propofol may be dependent on the type of LMA used. A previous study comparing the EC50 of the propofol concentration between classic and proseal LMA insertions demonstrated that the EC50 of propofol needed for proseal LMA insertion was 35% greater than that needed for classic LMA insertion. Unfortunately, no investigation has been performed to determine the EC50 of the propofol concentration required for i-gel insertion without muscle relaxants.
Dexmedetomidine (DEX), a selective alpha-2 agonist, has sympatholytic, sedative, and analgesic properties. Such beneficial characteristics make DEX a useful anaesthetic adjuvant for general anaesthesia. Many reports have revealed the beneficial effects of DEX in terms of reducing intraoperative anaesthetic requirements, postoperative analgesic demand, and increased haemodynamic responses to noxious stimuli such as endotracheal intubation. A previous investigation showed that preoperative clonidine, an alpha-2 agonist, decreased the EC50 required for LMA insertion.
We hypothesised that preoperative DEX administration can reduce the propofol concentration required for i-gel insertion. In this study, we compared the EC50 of propofol needed for successful i-gel insertion without muscle relaxants between DEX and placebo groups
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Single Group
- 主要目的
- Supportive Care
- 盲法
- Triple (Care Provider, Investigator, Outcomes Assessor)
入排标准
- 年龄范围
- 20 Years 至 65 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •ASA physical status I-II patients who were 20-65 years old and scheduled for general anaesthesia for urologic surgery
排除标准
- •Patients with an allergy to alpha-2 adrenergic agonists or propofol
- •Patients who anticipated difficult airway (cervical spinal disease, Mallampati score of III or IV, a mouth opening of <2.5 cm, and/or body mass index of >30 kg m-2), unstable teeth
- •Patients with bradycardia of <50 beats/min, heart block greater than first degree, severe cardiorespiratory dysfunction
- •Patients with symptoms of upper respiratory infection
结局指标
主要结局
EC50 of propofol required for successful i-gel insertion
时间窗: During i-gel insertion anticipated up to 1 min
The EC50 of propofol for successful i-gel insertion was determined by a modification of Dixon's up-and-down method. The response of each patient determined the effect-site propofol concentration for the next patient. If the response was deemed 'successful', the next target concentration of propofol was decreased by 0.5 µg mL-1. If the response was deemed a 'failure', the target concentration was increased by the same dose. The process was repeated until the sixth crossover point (success/failure) was obtained.
次要结局
- the total dose of propofol infused before i-gel insertion(During i-gel insertion time anticipated upto 1min)
- the presence/severity of airway trauma after i-gel insertion(At the time point of removing the i-gel from patient's mouth)
研究者
Hee-Pyoung Park
Associate Professor
Seoul National University Hospital