Albertin A, La Colla G, La Colla L, Bergonzi P C, Deni F, Moizo E
Department of Anesthesiology, IRCCS H. San Raffaele, Vita-Salute University of Milan, Milan, Italy.
Minerva Anestesiol. 2006 Nov;72(11):915-24.
The aim of this prospective study was to determine the effect site concentrations of remifentanil maintaining cardiovascular homeostasis in response to surgical stimuli during bispectral index (BIS) guided propofol anesthesia in seriously obese patients.
Twenty-two patients, female/male 15/7, ASA physical status II - III, aged 29-69 years, body mass index (BMI) 54.5+/-12, undergoing major open bariatric surgery, were enrolled to receive a propofol-remifentanil total intravenous anesthesia. All patients were intubated by using a flexible fiberoptic bronchoscopic technique facilitated by a target controlled effect site concentration of remifentanil set at 2.5 ng/mL. After endotracheal intubation, anesthesia was started with a target controlled infusion of propofol initially set at 6 microg/mL, then adjusted to maintain a BIS value between 40 and 50. The mean effect site concentration of remifentanil was recorded at different intervals time during surgery: skin incision-opening of peritoneum (T1), bowel resection (T2), cholecystojejunal anastomosis (T3), ileojejunal anastomosis (T4), closing of peritoneum (T5).
The mean plasma concentrations of propofol required to maintain a BIS value between 40 and 50 were 4+/-0.55, 3.8+/-0.64, 3.8+/- 0.63, 3.8+/-0.65 and 3.8+/-0.63 microg/mL at T1, T2, T3, T4 and T5 interval time, respectively. The mean values of remifentanil target effect site concentration were 5.2+/-1.3, 7.7+/-1.7, 9.1+/-1.8, 9.7+/- 2.2 and 9.9+/-2.5 ng/mL at T1, T2, T3, T4 and T5 interval time.
This study suggests that tolerance to remifentanil infusion is profound and develops very rapidly in morbidly obese patients submitted to open bariatric surgery during BIS guided propofol anesthesia. The administration of opiates during anesthesia based on target-controlled infusion should include corrections for the development of tolerance.
本前瞻性研究旨在确定在双谱指数（BIS）引导的丙泊酚麻醉期间，瑞芬太尼维持严重肥胖患者心血管稳态以应对手术刺激的效应室浓度。
22例患者，女性15例，男性7例，美国麻醉医师协会（ASA）身体状况分级为II - III级，年龄29 - 69岁，体重指数（BMI）为54.5±12，接受大型开放式减肥手术，接受丙泊酚 - 瑞芬太尼全静脉麻醉。所有患者均采用可弯曲纤维支气管镜技术插管，瑞芬太尼目标效应室浓度设定为2.5 ng/mL。气管插管后，开始以目标控制输注丙泊酚，初始设定为6 μg/mL，然后调整以维持BIS值在40至50之间。在手术期间的不同时间间隔记录瑞芬太尼的平均效应室浓度：皮肤切开 - 打开腹膜（T1）、肠切除（T2）、胆囊空肠吻合（T3）、回肠空肠吻合（T4）、关闭腹膜（T5）。
在T1、T2、T3、T4和T5时间间隔，维持BIS值在40至50之间所需的丙泊酚平均血浆浓度分别为4±0.55、3.8±0.64、3.8±0.63、3.8±0.65和3.8±0.63 μg/mL。在T1、T2、T3、T4和T5时间间隔，瑞芬太尼目标效应室浓度的平均值分别为5.2±1.3、7.7±1.7、9.1±1.8、9.7±2.2和9.9±2.5 ng/mL。
本研究表明，在BIS引导的丙泊酚麻醉期间，接受开放式减肥手术的病态肥胖患者对瑞芬太尼输注的耐受性很强且发展非常迅速。基于目标控制输注的麻醉期间阿片类药物的给药应包括对耐受性发展的校正。
