2%七氟醚两种低流量洗入半紧闭麻醉环路时的浓度变化

目的 观察2%七氟醚两种低流量洗入半紧闭环路的浓度变化.方法 选择40例AsA分级Ⅰ～Ⅱ级择期行外科手术的患者,随机分为A、B两组,两组洗入新鲜气体流量分别为2.0 L/min或1.0 L/min,七氟醚蒸发罐麻醉药设定浓度(F_D)为2%.记录肺泡内麻醉药浓度(F_A)、吸入麻醉药浓度(F_I)和FA/FI.结果 七氟醚低流量洗入120 min后A组F_A及F_I分别为(1.47±0.12)%和(1.69±0.09)%,B组分别为(1.23±0.13)%和(1.46±0.11)%,两组内的FA与F1比较差异有统计学意义(P＜0.01);F_A/F_D和F_I/F_D在A组分别为0.73 ±0.07和0.85±0.08,B组为0.62±0.06和0.73±0.07,两组间比较差异有统计学意义(P＜0.01).A、B两组中的F_A/F_I分别为0.87±0.08和0.85±0.09,两组比较差异无统计学意义(P＞0.05).结论 2%七氟醚低流量洗入麻醉环路120 min后对两组间的F_A和F_I有不同影响,但对两组间的F_A/F_I影响相似.     

地氟醚环路内注药法循环紧闭吸入麻醉的应用研究

目的：探讨地氟醚环路内注药法用于循环紧闭吸入麻醉的可行性,并观察地氟醚药代动力学的变化。方法：５０例ＡＳＡⅠ～Ⅱ级择期手术全麻病人,咪唑安定、芬太尼麻醉诱导插管行ＩＰＰＶ。氧流量４Ｌ／ｍｉｎ通气５分钟,行最低流量循环紧闭吸入麻醉。根据Ｌｏｗｅ的吸收公式,通过呼气端注入地氟醚的初始剂量,接着用微泵持续输入地氟醚,维持地氟醚的肺泡浓度（ＦＡ）约３％左右,术中根据地氟醚的ＦＡ调整输注速度。切皮前静注芬太尼０１ｍｇ,术中维库溴铵维持肌松,并辅以异丙酚２ｍｇ·ｋｇ－１·ｈ－１。记录地氟醚ＦＡ达３％的时间、呼气末浓度／吸气浓度（ＦＩ）达０８５的时间及其变化趋势。结果：地氟醚用量１０２４±１６３ｍｌ,地氟醚ＦＡ达３％的时间为１１±０４分钟,ＦＡ／ＦＩ达０８５的时间为３１±０１分钟,并能维持于０８５～０９５,恢复呼吸为５７±１３分钟,拔管时间为８３±０９分钟,睁眼时间８６±１６分钟。结论：采用低流量循环紧闭环路内注药法能安全有效地实施麻醉和减少环境污染。     

七氟醚麻醉时环路内麻醉药物浓度监测

七氟醚麻醉时环路内麻醉药物浓度监测潘贤＊李国红＊马亚群＊杜新民＊焦红馥＊＊北京军区总医院麻醉科（１００７００）图１低流量时各组吸入七氟醚浓度┐时间关系图２低流量时各组呼气末七氟醚浓度┐时间关系麻醉药物浓度监测对于掌握麻醉深度，保证病人安全有重要意义...     

紧闭循环麻醉时七氟醚对病人肝肾功能的影响

目的 评价紧闭循环麻醉时七氟醚对病人肝肾功能的影响.方法 拟行普外科手术病人40例,ASA Ⅰ或Ⅱ级,年龄20～60岁,随机分为2组(n=20),麻醉诱导后S1.组和S2组分别吸人6%～8%国产或进口七氟醚,新鲜气流量2～4 L/min,2～3 min后调整新鲜气流量至0.18～0.30 L/min,随后维持七氟醚呼气末浓度2.6%～3.5%.于术前、术毕、术后1、2、3和5 d时测定血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)活性、总胆红素(TB)、肌酐(Cr)、尿素(BUN)、β2-微球蛋白(β2-MG)浓度和尿液β2-MG浓度.结果 与术前比较,术毕、术后1、2 d时两组尿液β2-MG浓度升高(P<0.05),术后1～5血清ALT、AST活性和TB、Cr、BUN和β2-MG浓度差异无统计学意义(P0.05);各指标组间比较差异无统计学意义(P0.05).结论 紧闭循环麻醉时七氟醚对病人肝肾功能无明显影响.     

低流量紧闭麻醉的回路内七氟醚注药法

目的：采用回路内直接注入七氟醚为２５例病人行低流量紧闭麻醉。方法：将七氟醚液体分次注入钠石灰罐，首次量２ｍｌ，追加量每次１ｍｌ。七氟醚呼气末浓度维持在１％以上。结果：第１ｈ的七氟醚用量为６．９２±２．１６ｍｌ，第２ｈ为４．５７±０．６６ｍｌ（１４例）。首次注药２ｍｌ产生的最大吸入和呼出浓度分别为０．６％～１．７％和０．４％～１．３％。随着麻醉时间的延长，七氟醚的摄取速率减慢，追加给药产生的吸入浓度上升幅度逐渐增大。而七氟醚的用量与体重的相关性较差。结论：钠石灰罐分次注入七氟醚行低流量紧闭麻醉简便可行。     

地氟醚环路内注药法循环紧有入麻醉的应用研究

目的：探讨地氟醚环路内注药法用于循环紧闭吸入麻醉的可行性,并观察地氟醚药代动力学的变化,方法：５０例ＡＳＡⅠ－Ⅱ级择期手术全麻病人,咪唑安定、芬太尼麻醉诱导插管行ＩＰＰＶ。氧流量４Ｌ／Ｍｉｎ通气５分钟,行最低流量循环紧闭吸入麻醉。根据Ｌｏｗｅ的吸收公式,通过气端注入地氟醚的初始剂量,接用微泵持续输入地氟醚,维持地氟醚的肺泡浓度约３％左右。术中根据地氟醚的ＦＡ调整输注速度。切皮前分太尼０．１ｍｇ,术     

安氟醚低流量紧闭麻醉的临床观察

目的和方法：采用低流量（０．２Ｌ／ｍｉｎ）新鲜气体（氧）与安氟醚麻醉，并与高流量（２Ｌ／ｍｉｎ）安氟醚麻醉者比较。监测气管插管后５ｍｉｎ、１０ｍｉｎ、１５ｍｉｎ、３０ｍｉｎ和６０ｍｉｎ直至术终的ＭＡＰ、ＨＲ、ＳｐＯ２、Ｆ１Ｏ２、ＰＥＴＣＯ２、Ｆ１Ｅｎｆ、ＦＥＴＥｎｆ及新鲜气体流量。记录手术结束至拔管的时间及清醒程度。结果：两组差异均无显著性意义（Ｐ〉０．０５）。结论：低流量新鲜气体麻醉与高流量同样     

地氟醚紧闭麻醉

目的　探讨地氟醚紧闭麻醉的可行性。方法 65例 ASA ～ 级胸、上腹部手术病人行紧闭地氟醚麻醉。洗入期 ,氧气 1　 L· min- 1 ,Tec 6蒸发器刻度 18% ;维持期 ,氧气 ( 0 .18～ 0 .3 ) L· min- 1 ,依据血压和脑电指标调节地氟醚投入量。手术结束前约 3 0分关闭地氟醚 ,缝皮时氧气 1～ 5L· m in- 1洗出地氟醚。结果　平均洗入时间 ( 4 .0 4± 1.3 4)分 ,术中地氟醚吸入和呼气末平均体积分数分别为 ( 6.9± 1.4 8) %、( 6.4 0± 1.19) %。紧闭期地氟醚的投入量方程为 y=3 9.4 7t- 0 .1 61 4 。 2 4 0分地氟醚蒸气累计摄取量为 4 613 .5 7ml( 2 3 .86ml地氟醚液体 )。 3 0和 60分地氟醚利用率分别为 0 .89和0 .88。停药低流量维持期呼气末体积分数下降 5 0 %的时间为 ( 2 6.5 9± 6.18)分 ,完全清醒的平均时间为 ( 8.3 5± 3 .4 0 )分。结论　地氟醚紧闭麻醉是一种经济、安全、易控制的麻醉方法     

二氧化碳吸收剂中水分对七氟醚分解反应的影响

目的　研究模拟紧闭反应器内干燥的二氧化碳 (CO2 )吸收剂及自身含水对七氟醚分解的影响。方法　在紧闭反应器 (1 6 0ml)内 ,分别装钠石灰、钡石灰、干燥钠石灰和干燥钡石灰 (各 2 5g)。在密闭状态下注入液态的七氟醚 4 0 0 μl,放入 5 0℃水浴内反应 6h ,分别在 5、1 5、30、4 5、6 0min、以后每 30分钟至 36 0分钟采样 ,用气相色谱法分析。测定七氟醚的分解产物。结果　钠石灰组出现复合物A、B ,在其他组七氟醚产生 5种分解产物。复合物A∶干燥钡石灰 >干燥钠石灰 >钡石灰和钠石灰组。干燥钡石灰组明显高于其他两组 (P <0 0 5 )。复合物B∶干燥钡石灰组 <钡石灰组 <干燥钠石灰组 (P <0 0 5 )。复合物C、D、E ,以干燥钡石灰组最为明显 (P <0 0 5 )。各组均未检测到CO。结论　在 5 0℃的紧闭反应器内 ,七氟醚与干燥的CO2 吸收剂反应剧烈 ,未产生CO ;国产钠石灰优于钡石灰 ,在紧闭容器内自身含水可以抑制分解反应     

二氧化碳吸收剂对长时间低流量七氟醚麻醉呼吸回路中化合物A浓度的影响

目的 观察两种二氧化碳吸收剂(Dr(a)gersorb 800 plus,Sodasorb LF)对长时间(>4 h)低流最七氟醚吸入麻醉时呼吸回路中化合物A(Compound A,CA)生成的浓度,以及患者肝肾功能的影响.方法 择期全身麻醉手术患者24例,ASA Ⅰ或Ⅱ级,随机分为Dragersorb 800 plus组(D组)和Sodasorb LF组(I.F组),每组12例.术中采用低流量七氟醚吸入麻醉(呼气末浓度1.72%,新鲜氧气流量为800 ml/min).2 h后每隔1小时在呼气相气管插管中段抽取10 ml气体样品,用气相色谱榆测CA浓度.同时,分别在术前1 d和术后24 h检测患者血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、胆红素(BR)、肌酐(Cr)和尿素氮(BUN)浓度.结果 低流量吸入麻醉2～6 h,呼吸回路中D组CA浓度(11.01±3.40)ppm,LF组CA浓度均在仪器检测灵敏度(<0.1 ppm)以下.与手术前1 d比较,两组患者术后24 h ALT、AST、BR、Cr和BUN浓度变化差异无统计学意义.结论 两种二氧化碳吸收剂均可安全应用于长时间(4～6 h)低流量(800 ml/min)七氟醚吸人麻醉,不影响肝肾功能.     

低流量七氟烷吸入麻醉时不同二氧化碳吸收剂环路中化合物A浓度的比较及其对患者肝肾功能的影响

目的 比较低流量七氟烷吸入麻醉时不同二氧化碳吸收剂环路中化合物A(CA)的浓度,并探讨其对患者肝肾功能的影响.方法 择期全麻手术患者27例,年龄20～64岁,ASA Ⅰ或Ⅱ级,随机分为3组:Dr(a)gersorb 800 plus(R)组(D组,n=10)、Sodasorb组(S组,n=10)和Sodasorb LF组(LF组,n=7).快速诱导气管插管后,行机械通气,维持七氟烷呼气末浓度2%,调节氧流量500 ml/min,2 h后在呼吸回路Y型接口处,呼气相抽取10 ml气体样品,采用气相色谱法检测CA浓度.分别在术前1 d(T0)和术后24 h(T1)检测血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、胆红素(BR)、肌酐(Cr)和尿素氮(BUN)水平.结果 各组ALT、AST、BR、Cr和BUN水平组间、组内比较差异无统计学意义(P＞0.05);与D组比较,S组和LF组CA浓度降低(P＜0.01);与S组比较,LF组CA浓度降低(P＜0.01).结论 低流量七氟烷吸入麻醉(呼气末浓度2%维持2 h)时,呼吸环路中CA浓度均低于50 ppm,Sodasorb LF的产量最低,但对患者肝肾功能均无明显影响.     

低流量七氟烷吸入麻醉时不同二氧化碳吸收剂环路中化合物A浓度的比较及其对患者肝肾功能的影响

Objective To investigate the influence of different carbon dioxide (CO2) absorbents (Dr(a)gersorb 800 plus , Sodasorb,Sodasorb LF) on the production of compound A during low-flow sevoflurane anesthesia.Methods Twenty-seven ASA Ⅰ or Ⅱ patients aged 20-64 years were randomly assigned to three groups according to different CO2 absorbents: Dr(a)gersorb 800 plus' group (group D, n = 10), Sodasorb group (group S, n = 10) and Sodasorb LF group (group LF, n = 7). Anesthesia was maintained with low-flow (500 ml/min) sevoflurane inhalation (with the end-tidal sevoflurane concentration of approximately 2% ). At 2 h after low-flow sevoflurane anesthesia, gas samples were taken from the expiratory limb of the circuit. Compound A was detected by gas chromatography. Serum alanine transaminase (ALT), aspartate aminotransferase (AST), bilirubin (BR), urea nitrogen (BUN) and creatinine (Cr) levels were measured before (T0 ) and 24 h after operation (T1).Results The three groups were comparable with respect to age, body weight and height. After 2 h of low-flow sevoflurane anesthesia, compound A concentrations in the expiratory limb of the circuit were 11.6 ± 5.8 (group D), 2.1 ± 1.9 (group S)and ＜ 0.1 ppm (group LF), respectively. There were no significant changes in the serum ALT, AST, BR, BUN and Cr levels at 24 h after operation as compared with the preoperative baseline values in the three groups.Conclusion After 2 h of low-flow (500 ml/min) sevoflurane anesthesia, compound A concentrations within the circuit with different CO2 absorbents ( Dr(a)gersorb 800 plus' , Sodasorb, Sodasorb LF) are less than 50 ppm, with the lowest in Sodasorb LF.However, they have no significant effects on hepatic or renal function.     

Compound A concentrations during low-flow sevoflurane anesthesia correlate directly with the concentration of monovalent bases in carbon dioxide absorbents

Sevoflurane degrades to Compound A, which is nephrotoxic in rats. Potassium hydroxide (KOH) and sodium hydroxide (NaOH) are primary determinants of this degradation reaction. To address this, new carbon dioxide absorbents, such as Amsorb((R)) (A; Armstrong Medical, Coleraine, Northern Ireland), which contains neither KOH nor NaOH, Dr?gersorb 800 Plus((R)) (D; Dr?ger, Luebeck, Germany), and Medisorb((R)) (M; Datex-Ohmeda, Bromma, Sweden), which contain some NaOH (1% to 2%) and only trace amounts of KOH (0.003%), were recently developed. We compared Compound A concentrations using these three CO(2) absorbents during low-flow (1 L/min) sevoflurane anesthesia in surgical patients, with those using a conventional CO(2) absorbent, Dr?gersorb 800 (C). The mean Compound A concentrations +/- SD using C, A, D, and M were 18.7 +/- 2.5, 1.8 +/- 0.7, 13.3 +/- 3.5, and 11.2 +/- 2.6 ppm, respectively, with significant differences (P < 0.001; A versus C, A versus D, A versus M, C versus D, C versus M). Amsorb prevented the degradation of sevoflurane to Compound A, whereas Dr?gersorb 800 Plus and Medisorb decreased the degradation to Compound A. Implications: Sevoflurane degradation to Compound A is decreased by lowering the concentration of monovalent bases in the carbon dioxide absorbent (Dr?gersorb 800 Plus) [Dr?ger, Luebeck, Germany] and Medisorb) [Datex-Ohmeda, Bromma, Sweden]) and is virtually eliminated in the absence of these bases (Amsorb) [Armstrong Medical, Coleraine, Northern Ireland]).     

Only carbon dioxide absorbents free of both NaOH and KOH do not generate compound A during in vitro closed-system sevoflurane: evaluation of five absorbents

BACKGROUND: Insufficient data exist on the production of compound A during closed-system sevoflurane administration with newer carbon dioxide absorbents. METHODS: A modified PhysioFlex apparatus (Dr?ger, Lübeck, Germany) was connected to an artificial test lung (inflow at the top of the bellow approximately/= 160 ml/min CO2; outflow at the Y piece of the lung model approximately/= 200 ml/min, simulating oxygen consumption). Ventilation was set to obtain an end-tidal carbon dioxide partial pressure of approximately 40 mmHg. Various fresh carbon dioxide absorbents were used: Sodasorb (n = 6), Sofnolime (n = 6), and potassium hydroxide (KOH)-free Sodasorb (n = 7), Amsorb (n = 7), and lithium hydroxide (n = 7). After baseline analysis, liquid sevoflurane was injected into the circuit by syringe pump to obtain 2.1% end-tidal concentration for 240 min. At baseline and at regular intervals thereafter, end-tidal carbon dioxide partial pressure, end-tidal sevoflurane concentration, and canister inflow (T degrees(in)) and canister outflow (T degrees(out)) temperatures were measured. To measure compound Ainsp concentration in the inspired gas of the breathing circuit, 2-ml gas samples were taken and analyzed by capillary gas chromatography plus mass spectrometry. RESULTS: The median (minimum-maximum) highest compound Ainsp concentrations over the entire period were, in decreasing order: 38.3 (28.4-44.2)* (Sofnolime), 30.1 (23.9-43.7) (KOH-free Sodasorb), 23.3 (20.0-29.2) (Sodasorb), 1.6 (1.3-2.1)* (lithium hydroxide), and 1.3 (1.1-1.8)* (Amsorb) parts per million (*P < 0.01 vs. Sodasorb). After reaching their peak concentration, a decrease for Sofnolime, KOH-free Sodasorb, and Sodasorb until 240 min was found. The median (minimum-maximum) highest values for T degrees(out) were 39 (38-40), 40 (39-42), 41 (40-42), 46 (44-48)*, and 39 (38-41) degrees C (*P < 0.01 vs. Sodasorb), respectively. CONCLUSIONS: With KOH-free (but sodium hydroxide [NaOH]-containing) soda limes even higher compound A concentrations are recorded than with standard Sodasorb. Only by eliminating KOH as well as NaOH from the absorbent (Amsorb and lithium hydroxide) is no compound A produced.     

Carbon dioxide absorbents containing potassium hydroxide produce much larger concentrations of compound A from sevoflurane in clinical practice

We investigated the concentrations of degraded sevoflurane Compound A during low-flow anesthesia with four carbon dioxide (CO(2)) absorbents. The concentrations of Compound A, obtained from the inspiratory limb of the circle system, were measured by using a gas chromatograph. In the groups administered 2 L/min fresh gas flow with 1% sevoflurane, when the conventional CO(2) absorbents, Wakolime(TM) (Wako, Tokyo, Japan) and Dr?gersorb(TM) (Dr?ger, Lübeck, Germany), were used, the concentrations of Compound A increased steadily from a baseline to 14.3 ppm (mean) and 13.2 ppm, respectively, at 2 h after exposure to sevoflurane. In contrast, when the other novel types of absorbents containing decreased or no potassium hydroxide/sodium hydroxide, Medisorb(TM) (Datex-Ohmeda, Louisville, CO) and Amsorb(TM) (Armstrong, Coleraine, Northern Ireland), were used, Compound A remained at baseline (<2 ppm) throughout the study. In the groups administered 1 L/min fresh gas flow with 2% sevoflurane, Wakolime(TM) and Dr?gersorb(TM) produced much larger concentrations of Compound A (35.4 ppm and 34.2 ppm, respectively) at 2 h after exposure to sevoflurane. Medisorb(TM) showed measurable concentrations of Compound A (8.6 ppm at 2 h), but they were significantly smaller than those produced by the two conventional absorbents. In contrast, when Amsorb(TM) was used, Compound A concentrations remained at baseline throughout the study period. IMPLICATIONS: Carbon dioxide absorbents containing potassium hydroxide/sodium hydroxide produce much larger concentrations of Compound A from sevoflurane in clinical practice. An absorbent containing neither potassium hydroxide nor sodium hydroxide produces the smallest concentrations of Compound A.     

Cerebrovascular carbon dioxide reactivity during general anesthesia: a comparison between sevoflurane and isoflurane

We compared cerebrovascular carbon dioxide reactivity during the administration of sevoflurane and isoflurane anesthesia by measuring cerebral blood flow velocity (CBFV) as an indirect measurement of cerebral blood flow. Thirty patients, 20-70 yr old, undergoing lower abdominal surgery and without known cerebral or cardiovascular system disease, were randomly assigned to either sevoflurane or isoflurane treatment groups. Anesthesia was induced with thiopental 5 mg/kg IV and maintained with either sevoflurane or isoflurane in 67% nitrous oxide and oxygen. The CBFV and pulsatility index (PI) of the left middle cerebral artery were monitored with transcranial Doppler. The P(ETCO)2 was increased stepwise from 20 to 50 mm Hg by changing the respiratory rate with a constant tidal volume. At every 5-mm Hg stepwise change in P(ETCO)2, CBFV and PI were recorded. CBFV increased with increasing P(ETCO)2. CBFV was significantly smaller in the isoflurane group at P(ETCO)2 = 20-40 mm Hg than in the sevoflurane group. The rate of change of CBFV with changes in CO2 was larger in the isoflurane group than in the sevoflurane group. PI was constant over time and was not different between groups. In conclusion, hypocapnia-induced reduction of intracranial pressure might be more effective during the administration of isoflurane than sevoflurane. IMPLICATIONS: Changes in cerebral blood flow caused by the changes of carbon dioxide tension are greater during the administration of isoflurane anesthesia compared with sevoflurane anesthesia. Attempts to decrease intracranial pressure by decreasing carbon dioxide tension may be more successful during isoflurane than sevoflurane anesthesia administration.