预测控制加智能控制用于七氟醚闭合环路定量麻醉的可行性

Predictive and intelligent control of sevoflurane closed circuit anesthesia

目的探讨自制的伺服控制闭合麻醉系统、预测控制加智能控制用于七氟醚定量麻醉的可行性。方法143例ASAⅠ-Ⅲ级病人,静脉注射芬太尼2-3μg·kg-1、咪唑安定0.12mg·kg-1、维库溴铵0.1mg·kg-1诱导插管后,使用由IBM计算机、氧气质量流量控制器、电控七氟醚注射泵组成的伺服控制全麻系统向呼吸环路中送入氧气和七氟醚,氧气的新鲜气流量为[体重(kg)3/4×10+20]ml·min-1。用预测控制加智能控制法控制七氟醚呼气末浓度为1.3MAC。结果洗入时间(5.2±2.4)min,麻醉洗入和维持期间的新鲜气流量为(0.22±0.04)L·min-1。七氟醚的累积摄取量为:5.16ml(30min)、7.74ml(60min)、9.17ml(90min)、11.08ml(120min)、12.47ml(150min)、13.00ml(180min)、14.18ml(210min)、15.60ml(240min)、18.56ml(300min)和24.60ml(420min)。在420min中,七氟醚注入速率的三指数方程为(0.2673e-0.0598t+0.2269e-0.0597t+0.1150e-0.0021t)ml·min-1。结论预测控制加智能控制可控制多因素干扰下的设定的七氟醚呼气末浓度,是一种安全有效的方法。

Objective To evaluate the efficacy of servo controlled sevoflurane closed-circuit anesthesia and the feasibility of the predictive and intelligent control.Methods One hundred and forty-three ASA Ⅰ-Ⅲ patients (90 males, 53 females) aged between 3-77 yrs undergoing elective surgery were studied. Anesthesia was induced with intravenous fentanyl 2-3 μg ·kg-1 , midazolam 0.12 mg·kg-1 and vecuronium 0.1 mg·kg-1 . After tracheal intubation the tracheal tube was connected to the servo-controlled closed-circuit system composed of IBM computer, O2 mass flow controller and electrically controlled sevoflurane injection pump and multifunctional monitor. The fresh gas flow of O2 = [body weight (kg)3/4 × 10 + 20] ml·min-1 . The end-expired sevoflurane concentration was maintained at 1.3 MAC by predictive and intelligent control.Results The average wash-in time to reach the target concentration was (5.2 ±2.4) min. The O2 flow rate was(0.22±0.04) L·min-1 . The cumulative uptake of sevoflurane was 5.16 ml, 7.74ml, 9.17ml, 11.08ml, 12.57ml, 13.00ml, 14.18ml, 15.60ml, 18.56ml and 24.6 ml at 30, 60, 90, 120, 150, 180, 210, 240, 300 and 420 min respectively. The uptake rate of fluid sevoflurane was equivalent to (0.2673e-0.0598t + 0.2269e-0.0597t + 0.1150e-0.002t) ml·min-1 . Conclusion The servo controlled sevoflurane closed-circuit system can effectively control the pre-set end-tidal sevoflurane concentration in spite of the influence of multiple factors and is safe and effective.