The Effect of Sevoflurane on Cerebral Vasoreactivity Ans Systemic Arteries
试验速览
- 阶段
- 4 期
- 状态
- 已完成
- 入组人数
- 24
- 试验地点
- 1
- 主要终点
- Blood flow velocity in the middle cerebral artery
研究概览
简要总结
Purpose:
- The purpose of this study is to examine the effect of different carbon-dioxide concentrations on cerebral CO2 sensitivity and the resistance and stiffness of systemic arteries during anesthesia with sevoflurane. Sevoflurane is a widely and commonly used inhalational anaesthetic, that is mainly used for the maintenance of general anesthesia.
- Changes in the velocity of cerebral blood flow and arterial stiffness due to the different exhaled carbon-dioxide concentrations will allow us to conclude how sevoflurane affects these parameters during the course of the narcosis.
Instruments:
- An ultrasound device called transcranial doppler (TCD) is used to measure the velocity of blood flow within a main artery located inside the skull.
- A tonometry device named SphygmoCor is used to assess the pressure wave proceeding in the radial artery, from which the stiffness of the systemic vessels can be concluded.
Measurements:
- Examinations with the ultrasound and tonometry devices are carried out once before the operation, three times during the intervention, with different exhaled CO2 values and once after the operation is completed.
Hypothesis:
- Sevoflurane alters cerebral carbon-dioxide sensitivity and the stiffness of systemic arteries.
详细描述
Study protocol:
- The study is conducted in four stages: in the first stage, measurements are performed preoperatively in awake patients. Patients are placed in supine position and mean arterial blood pressure (MAP), heart rate, oxygen saturation are measured. The transcranial doppler (TCD) probe is fixed in place by applying a headband to maintain a constant angle of insonation. Mean blood flow velocity (MBFV) and pulsatility index (PI) in the middle cerebral artery (MCA) are obtained. MCA is insonated through the right temporal window by using pulsed 2 megahertz TCD ultrasound probe. Identification of the MCA is confirmed by using standard criteria, at a depth of 45-55 mm. Cerebral CO2 vasoreactivity is calculated as the percentage change in MBFV or PI for mmHg change in end-tidal CO2 (ETCO2).
SphygmoCor is placed on the left radial artery to obtain data about the central aortic blood pressure, augmentation pressure (AP) and augmentation index normalised to a 75 beat per minute heart rate (Alx75). From the derived aortic pulse, calculations can be made, using the area under the systolic and diastolic part of the curve, to determine the heart's ratio of oxygen supply and demand, it is called the subendocardial viability ratio (SEVR).
As part of the premedication each patient receives 7.5 mg midazolam. Anaesthesia is induced using 2 mcg/kg fentanyl followed by 2 mg/kg propofol. Afterwards 0.6mg/kg rocuronium is given for muscle paralysis and subsequently patients were intubated with a suitable intratracheal tube.
After induction of anaesthesia, the patients are placed on a mechanical ventilation system, using a volume-controlled setting with an air and oxygen mixture set to 0.4 fraction of inspired oxygen (FiO2) , the fresh gas flow rate to 2 l/min and sevoflurane is adjusted to reach a constant 1minimal alveolar concentration (MAC) during examination. Anesthesia is maintained with sevoflurane and on demand fentanyl boluses.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 60 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Above the age 18
- •American Society of Anesthesiologists (ASA) physical classification I. or II.
- •Patients undergoing elective varicotomy or inguinal hernioplasty in general anesthesia
排除标准
- •Patients with cerebral, cardiac or systemic vascular disorders (hypertension, diabetes)
- •Patients receiving medication that affects the blood vessels (antihypertensive, antidiabetic, antiarrhythmic medications)
研究组 & 干预措施
Sevoflurane
Sevoflurane was administered to all patients at 1 minimal alveolar concentration (MAC) after the intubation occured until the patient was extubated.
干预措施: Partial pressure of CO2 at the end of an exhaled breath (Procedure)
Sevoflurane
Sevoflurane was administered to all patients at 1 minimal alveolar concentration (MAC) after the intubation occured until the patient was extubated.
干预措施: Sevoflurane (Drug)
结局指标
主要结局
Blood flow velocity in the middle cerebral artery
时间窗: Changes from baseline in blood flow velocity at the 15th, 20th and 25th minutes of the operation
Systolic, diastolic and mean blood flow velocities are measured with transcranial doppler device.
次要结局
- Arterial wall stiffness of the radial artery(Changes from baseline in arterial stiffness at the 15th, 20th and 25th minutes of the operation)
- Changes in the central systolic and diastolic blood pressure(Changes from baseline in central blood pressure at the 15th, 20th and 25th minutes of the operation)
研究者
Tamas Vegh, MD
assistant lecturer anesthesiologist and intensive care specialist
University of Debrecen