A Comparative Evaluation of Sevoflurane Consumption and Anesthetic Depth During the Initial Phase of Minimal-Flow Versus Low-Flow Anesthesia in Patients Undergoing Retrograde Intrarenal Surgery (RIRS)
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 62
- 试验地点
- 1
- 主要终点
- Total Sevoflurane Consumption (mL)
研究概览
简要总结
This study aimed to compare the effects of minimal-flow (0.5 L/min) and low-flow (1.0 L/min) sevoflurane anesthesia on agent consumption, anesthetic depth, and cardiorespiratory safety during retrograde intrarenal surgery (RIRS). A total of 62 adult patients undergoing elective RIRS were enrolled in this single-center interventional trial. Patients were divided into two groups based on the fresh gas flow rate used during the maintenance phase of anesthesia. The primary outcome was total sevoflurane consumption at the end of anesthesia. Secondary outcomes included time to reach 1 minimum alveolar concentration (MAC), vaporizer shut-off time, BIS values, MAC levels, and respiratory parameters. The study found that minimal-flow anesthesia was as effective and safe as low-flow anesthesia, with lower agent consumption and no adverse effects on hemodynamic or respiratory parameters. These findings support the use of minimal-flow anesthesia for improved cost-efficiency and environmental sustainability.
详细描述
This prospective, single-center, interventional study was designed to evaluate and compare the effects of minimal-flow and low-flow anesthesia on sevoflurane consumption, anesthetic depth, and respiratory parameters during retrograde intrarenal surgery (RIRS). After obtaining ethics committee approval (Decision No: 2024/16/925, Date: 17.09.2024), a total of 62 adult patients undergoing elective RIRS under general anesthesia were enrolled and divided into two groups based on the fresh gas flow rate used during the maintenance phase of anesthesia.
In Group 1 (Minimal-flow group), the fresh gas flow was reduced to 0.5 L/min after the initial 10 minutes of anesthesia. In Group 2 (Low-flow group), a 1.0 L/min flow rate was maintained. Both groups received the same induction and maintenance protocols with sevoflurane, and depth of anesthesia was monitored via BIS (Bispectral Index). Key variables measured included the total amount of sevoflurane consumed (mL), the time to reach 1 MAC, the vaporizer shut-off time, intraoperative BIS and MAC values, EtCO₂, and respiratory rate. Safety outcomes such as hemodynamic stability and desaturation were also recorded.
The primary outcome was total sevoflurane consumption. Secondary outcomes included anesthetic depth consistency (BIS/MAC), respiratory parameters, and time-based metrics. Statistical analysis revealed that minimal-flow anesthesia significantly reduced sevoflurane usage without compromising patient safety or anesthetic depth.
The results support the clinical use of minimal-flow anesthesia as a safe, cost-effective, and environmentally favorable alternative to low-flow techniques in selected urological procedures.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- None
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
- •Adults aged 18 to 65 years
- •ASA (American Society of Anesthesiologists) Physical Status I or II
- •Scheduled to undergo elective retrograde intrarenal surgery (RIRS) under general anesthesia
- •Provided written informed consent
- •Able to cooperate with preoperative evaluation procedures
排除标准
- •ASA Physical Status III or higher
- •History of respiratory disease (e.g., asthma, COPD, restrictive lung disease)
- •Known hepatic or renal dysfunction
- •Neurological or psychiatric disorders that may affect BIS monitoring or anesthetic response
- •Known allergy or hypersensitivity to sevoflurane or other volatile anesthetics
- •Pregnancy or breastfeeding
- •Obesity (BMI > 30 kg/m²)
- •Anticipated difficult airway or history of intubation complications
- •Participation in another clinical trial within the past 30 days
研究组 & 干预措施
Minimal-flow Sevoflurane Group
Participants in this group received general anesthesia using sevoflurane with a fresh gas flow rate reduced to 0.5 L/min after the initial 10 minutes of induction. Anesthesia depth was monitored using BIS, and agent consumption and respiratory parameters were recorded throughout the retrograde intrarenal surgery (RIRS) procedure.
干预措施: Sevoflurane Anesthesia with Minimal-flow (Drug)
Low-flow Sevoflurane Group
Participants in this group received general anesthesia using sevoflurane with a consistent 1.0 L/min fresh gas flow during the maintenance phase. BIS monitoring, agent consumption, and respiratory parameters were recorded throughout the retrograde intrarenal surgery (RIRS).
干预措施: Sevoflurane Anesthesia with Low-flow (Drug)
结局指标
主要结局
Total Sevoflurane Consumption (mL)
时间窗: End of surgery (approximately 60-90 minutes after anesthesia induction)
Total volume of sevoflurane (in milliliters) used during the maintenance phase of general anesthesia, calculated automatically by the anesthesia machine and recorded at the end of surgery.
次要结局
未报告次要终点
研究者
Umit Yildiz
Medical Doctor in Anesthesiology and Reanimation
Dr. Lutfi Kirdar Kartal Training and Research Hospital