七氟醚控制性降压对脑代谢的影响

目的 观察七氟醚控制性降压的效果及对脑氧供需平衡、脑能量代谢的影响,并与硝普钠（ＳＮＰ）降压进行对比。方法 择期手术病人４０例随机分为三组：Ｉ组七氟醚降压组,Ⅱ组七氟醚常压组和Ⅲ组ＳＮＰ降压组。Ｉ组增加七氟醚吸入浓度,Ⅲ组静滴ＳＮＰ溶液,降至基础值的５０％～６０％持续４０ｍｉｎ,连续监测ＭＡＰ、ＨＲ、及ＥＣＧ,并同步采集桡动脉和颈内静脉血行血气分析,计算动－颈内静脉氧含量差（Ｄａ－ｊｖＯ２）;测定     

硝普钠-艾司洛尔用于神经外科控制性降压的临床研究

目的　研究硝普钠或硝普钠 艾司洛尔用于轻或中度颅内高压患者控制性降压对脑氧代谢和颅内压的影响。方法　 1 8例颅内压轻度增高的颅内肿瘤患者 ,在持续丙泊酚静脉麻醉 (目标血浓度 5 μg/ml)下行开颅手术。采用硝普钠或硝普钠 艾司洛尔控制性降压至动脉压 6 4～ 6 8/ 4 0～4 5mmHg,持续 1h。监测降压前后及降压期间颈内静脉血氧饱和度及动脉氧分压、颅内压、心率、血压变化。结果　在丙泊酚全身麻醉下硝普钠降压不引起颅内压增高 ,脑氧代谢良好。合并使用艾司洛尔 5 0 μg·kg 1 ·min 1 ,有助于维持较低的颅内压 ,并可减慢心率 ,防止硝普钠停药后反跳性高血压 ,硝普钠用量亦减少约 4 5 %。结论　硝普钠降压用于丙泊酚静脉麻醉的神经外科病人 ,脑氧代谢良好 ,联合使用硝普钠、艾司洛尔优于单纯使用硝普钠     

七氟醚控制性降压对脑氧供需平衡的影响

目的：观察七氟醚降压对脑氧供需平衡状态的影响,并与硝普钠（ＳＮＰ）进行对比。方法：择期手术病人３６例,随机分为Ⅰ组七氟醚降压组,Ⅱ组七氟醚常压组和Ⅲ组ＳＮＰ降压组,Ⅰ组增加七氟醚吸入浓度,Ⅲ组静滴ＳＮＰ溶液,降低血压持续４０分钟,连续监测ＭＡＰ、ＨＲ、及ＥＣＧ,并同步采集桡动脉和颈内静脉血行血气分析,计算脑氧摄取率（ＥＲＯ２）,动－静脉氧含量差（Ｄａ－ｊｖＯ２）。结果：Ⅰ组降压后ＥＲＯ２、Ｄａ－ｊ     

硝普钠控制性降压对血液动力学及脑氧平衡的影响

目的 研究硝普钠控制性降压对颅内手术病人血液动力学及脑氧供需平衡的影响。方法 择期颅内手术病人12例，用硝普钠使平均动脉压(MAP)降至50～65mmHg，并维持30min。降压前后，自桡动脉和颈内静脉球部取血进行血气分析和血糖测定，并以CO2复吸人法无创心排血量监舅仪(NiCO2)连续监测心排血量(CO)。结果 (1)降压期间，HR明显加快，CO先下降后又回升至降压前水平;颈静脉血氧饱和度无明显下降；(2)动-颈内静脉球部氧含量差、脑氧摄取率、动-颈内静脉糖含量差和脑葡萄糖摄率麻醉后均显著下降，降压及停降压后均进一步下降，仅脑氧摄取率降压后稍增加。结论 硝普钠控制性降压时心率增快，CO无明显变化，脑氧供需可维持平衡，但对葡萄糖的利用减少。     

七氟醚和硝普钠控制性降压对犬血液动力学影响的对比研究

目的：比较七氟醚和硝普钠控制性降压对犬血液动力学的影响。方法：将１４只杂种犬随机分为七氟醚组和硝普钠组，吸入七氟醚或静滴硝普钠，使ＭＡＰ降至８ｋＰａ，维持３０分钟后停药，持续监测ＭＡＰ、ＨＲ、ＣＯ、ＣＶＰ、ＳＶ和ＳＶＲ等指标。结果：在控制性降压期间，七氟醚组和硝普钠组ＣＯ分别减少３０．７％和２１．６％，七氟醚组ＨＲ明显减慢（Ｐ〈０．０１），而硝普钠组则不明显；硝普钠和七氟醚均降低ＳＶＲ，且硝普钠得     

显微外科听神经瘤切除术的麻醉

目的　探讨显微外科听神经瘤手术中麻醉处理 ,评价异丙酚输注对硝普钠控制性降压的影响。　方法　 2 0例显微外科听神经瘤手术的麻醉 ,麻醉诱导应用静注咪唑安定、芬太尼、阿曲库铵、异丙酚、利多卡因 ,吸入异氟醚后经鼻气管插管 ,间歇正压通气。以咪唑安定、芬太尼、氯胺酮、异丙酚、利多卡因复合异氟醚维持麻醉。使用硝普钠联合异丙酚控制性降压 ,并在降压前后进行血糖、动脉血气和血乳酸浓度分析。　结果　所有手术都顺利完成。术中通气指标维持稳定 ,控制性降压前后血糖、动脉血气和血乳酸浓度差异无显著性 (P >0 0 5 )。　结论　在听神经瘤显微外科手术 ,选择合适的麻醉、加强麻醉管理、完善麻醉监测手段和合理的控制性降压方法 ,利于维持脑氧供需平衡 ,是降低手术麻醉风险的重要措施。     

七氟醚控制性降压用于颅脑手术对围术期患者血流动力学和脑氧代谢的影响

目的研究七氟醚控制性降压用于颅脑手术对围术期血流动力学和脑氧代谢的影响。方法选择择期颅脑手术患者37例,ASA I或II级,在全身麻醉后,随机分为两组,分别给予七氟醚(S组,n=20)和硝普钠(N组,n=17)行控制性降压。监测术中HR、BP、SpO2、ECG,桡动脉、右颈内动脉球部抽血标本行血气分析,计算颈内静脉球部血氧含量差(Da-jvO2)、脑氧代谢率(CMRO2)、心率收缩压乘积(RPP)。结果 S组在降压达到目标MAP时,各时点的HR明显慢于N组(P0.05)。两组Da-jvO2、CMRO2在降压时均下降(P0.05),但两组差异无统计学意义。S组RPP在降压期间明显低于N组(P0.05)。结论七氟醚控制性降压更能稳定血流动力学状态,同时改善脑氧代谢。     

控制性降压用于脑膜瘤切除术的观察

控制性降压在颅脑手术中应用较广。我院对脑膜瘤切除手术,应用硝普钠一异氟醚控制性降压取得了良好的效果。1 资料与方法1.1 一般资料 20例脑膜瘤择期手术患者,ASAI～2级,男12例,女8例,年龄20～68岁,其中巨大脑膜瘤5例。术前血、尿常规检查以及电解质、肝、肾功能和心电图检查未见明显异常。1.2 麻醉方法 术前30min肌注苯巴比妥钠0.1g,东莨菪碱0.3mg,麻醉诱导用药:2.5%硫贲妥钠、25%r-羟基丁酸钠、芬太尼-氟哌啶合剂、氯化琥珀胆碱快速气管内插管。术中以维库溴铵、维持肌松,吸入异氟醚并间断静注芬太尼维持麻醉。采用北美Drager麻醉机间歇正压通气V_T8-10ml·kg~(-1)。监测 左桡动脉穿刺置务测MAP,锁骨下静脉穿刺置管测CVP,用HP-1205型监护仪连续测ECG、SPO_2,用英国佳士比3500泵控制硝普钠     

硝普钠控制性降压对老年高血压患者髋关节置换术后认知功能和脑氧代谢的影响

目的 观察硝普钠控制性降压对老年高血压患者髋关节置换术后认知功能和脑氧代谢的影响.方法 择期行髋关节置换术的老年高血压患者60例,年龄65～82岁,ASAⅡ级,随机均分为N组和C组.N组手术开始后,泵注硝普钠行控制性降压,MAP下降幅度在30%左右,保证MAP不低于55 mmHg,术毕停止降压.C组不行控制性降压.于术前1 d、术后4 d测定简易智力状态检查表(MMSE)评分.于麻醉诱导前(T0)、降压后30 min(T1)(C组在相应时间点)和术后30min(T2)同步采集桡动脉和颈内静脉血行血气分析,计算动脉血氧含量(CaO2)、颈内静脉球部血氧含量(CjvO2)、动脉-颈内静脉血氧含量差(Da-jvO2)和脑氧摄取率(CERQ2).结果 两组共有13例术后4 d发生术后认知功能障碍(POCD),其中N组7例(23.3%),C组6例(20.0%).N组在降压后Da-jvO2和CERO2有一定程度的增加但仍在正常范围之内.两组患者各时点CaO2、CjvO2、Da-jvO2和CERO2组内、组间比较差异无统计学意义.结论 硝普钠控制性降压在老年高血压患者髋关节置换术中应用并不增加POCD的发生率,脑氧代谢对POCD的影响有待进一步研究.     

不同剂量瑞芬太尼复合七氟醚控制性降压对神经外科手术患者脑氧代谢的影响

目的观察瑞芬太尼复合七氟醚控制性降压对神经外科手术患者脑氧代谢的影响。方法选择拟行控制性降压的神经外科手术患者60例,随机均分为三组:R1组为瑞芬太尼3ng/ml复合七氟醚组,瑞芬太尼效应室靶浓度设定为3ng/ml;R2组为瑞芬太尼6ng/ml复合七氟醚组,瑞芬太尼效应室靶浓度设定为6ng/ml;N组为硝普钠组。R1、R2组同时吸入七氟醚,控制七氟醚呼出气浓度为1MAC,N组泵注硝普钠的速率为1～3μg·kg-1·min-1。记录麻醉前10min(T0)、降压后10min(T1)、30min(T2)、停止降压10min(T3)、30min(T4)时的MAP和HR,采集相应时点的颈内静脉血和动脉血作血气分析,计算动脉血氧含量(CaO2)、颈内静脉球部血氧含量(CjvO2)、脑动-静脉血氧含量差(Da-jvO2)、脑氧摄取率(CERO2)。结果 T1～T4时R1、R2组,T1、T2时N组MAP明显低于T0时(P<0.01),T2时R2组MAP明显低于N组和R1组(P<0.05或P<0.01)。T1～T4时N组HR明显快于T0时和R1、R2组(P<0.01),T1～T3时R1、R2组HR明显慢于T0时,而T2时R2组HR明显慢于R1组(P<0.05或P<0.01)。T1～T4时三组CjvO2明显高于T0时(P<0.01),而Da-jvO2与CERO2明显低于T0时(P<0.01),T1、T2时R1、R2组CjvO2高于N组(P<0.05),而Da-jvO2与CERO2低于N组(P<0.05)。结论瑞芬太尼复合七氟醚控制性降压可降低神经外科手术患者的脑氧代谢,降压平稳迅速,HR缓慢,停止降压后无BP反跳现象,有利于围术期脑保护。     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

A Teaspoon Pump for Pumping Blood with High Hydraulic Efficiency and Low Hemolysis Potential

Abstract: Virtually all blood pumps contain some kind of rubbing, sliding, closely moving machinery surfaces that are exposed to the blood being pumped. These valves, internal bearings, magnetic bearing position sensors, and shaft seals cause most of the problems with blood pumps. The original teaspoon pump design prevented the rubbing, sliding machinery surfaces from contacting the blood. However, the hydraulic efficiency was low because the blood was able to "slip around" the rotating impeller so that the blood itself never rotated fast enough to develop adequate pressure. An improved teaspoon blood pump has been designed and tested and has shown acceptable hydraulic performance and low hemolysis potential. The new pump uses a nonrotating "swinging" hose as the pump impeller. The fluid enters the pump through the center of the swinging hose; therefore, there can be no fluid slip between the revolving blood and the revolving impeller. The new pump uses an impeller that is comparable to a flexible garden hose. If the free end of the hose were swung around in a circle like half of a jump rope, the fluid inside the hose would rotate and develop pressure even though the hose impeller itself did not "rotate"; therefore, no rotating shaft seal or internal bearings are required.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Tissue perfusion in relation to cardiac output during continuous positive-pressure ventilation and administration of propranolol or verapamil

Background : Our objective was to determine whether administration of propranolol or verapamil modifies the hemodynamic adaptation to continuous positive-pressure ventilation (CPPV), in particular the regional distribution of cardiac output (CO).
Methods : General hemodynamics and regional blood flows assessed by microsphere technique (15 (μm) were recorded in 16 anesthetized pigs during spontaneous breathing (SB) and CPPV with 8 cm H₂O end-expiratory pressure (CPPV8) before and after intravenous administration of propranolol (0.3 mg · kg⁻¹ followed by 0.15 mg · kg⁻¹ · h⁻¹, n=8) or verapamil (0.1 mg · kg⁻¹ followed by 0.3 mg · kg⁻¹ · h⁻¹, n=8).
Results : CPPV8 depressed CO by 25% without shifts in its relative distribution with the exception of a noteworthy increase in adrenal perfusion. Propranolol increased arterial blood pressure, and due to a fall in heart rate, CO dropped by 25%. The kidneys and, to a lesser extent, the splanchic region and central nervous system received increased fractions of the remaining CO at the expense of skeletal muscle flow. Similar patterns were seen during SB and CPPV8 such that the combination of propranolol and CPPV8 depressed CO by 50%. The circulatory effects of verapamil were less evident but myocardial perfusion tended to increase.
Conclusions : The combination of propranolol or verapamil with CPPV does not result in any specific hemodynamic interaction in anesthetized pigs, except that the combined effect of propranolol and CPPV may severely reduce CO.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

Background : Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.
Methods : Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.
Results : At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1±1.2% (mean±SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2±1.2%), sevoflurane (to 4.4±0.9%) or halothane (to 3.2±1.5%) (each P <0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.
Conclusion : Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

A comparison of the inhibitory effects of four volatile anaesthetics on the metabolism of chlorzoxazone, a substrate for CYP2E1, in rabbits

Background: Halothane inhibits in vitro and in vivo activity of cytochrome P-450 (CYP) 2E1. There are several fluorinated volatile anaesthetics besides halothane, and most of them are defluorinated by CYP2E1. It is unclear whether other fluorinated anaesthetics inhibit the in vivo activity of CYP2E1.
Methods: We compared the inhibitory effects of therapeutic concentrations of four inhalational anaesthetics, halothane, enflurane, isoflurane, and sevoflurane, on chlorzoxazone metabolism in rabbits receiving artificial ventilation.
Results: All four inhalational anaesthetics decreased arterial blood pressure and increased plasma chlorzoxazone concentration. However, no significant differences in the plasma chlorzoxazone concentration were found between the four anaesthetics. The estimated chlorzoxazone clearance increased after beginning inhalation with all four agents, but no significant difference in clearance was noted between agents.
Conclusions: At therapeutic concentrations, the in vivo inhibitory effect on chlorzoxazone metabolism was similar for all four inhalational anaesthetics examined, even though their chemical characteristics and extent of hepatic metabolism differ considerably.