后路短节段椎弓根内固定加植骨融合治疗儿童先天性脊柱后凸

[目的]探讨后路短节段椎弓根钉内固定加植骨融合矫正儿童先天性半椎体脊柱后凸畸形的可行性及短期疗效评价。[方法]对2001年11月～2006年1月挑选的13例先天性半椎体脊柱后凸儿童进行后路短节段椎弓根钉内固定加植骨融合畸形矫正术，男8例，女5例；平均10．4岁（5～13岁）。Cobb’s角平均为42．7^o（28^o～48^o）。术后支具固定8个月。[结果]术后X线片随访12个月-5年3个月（平均2年3个月）。矢状面Cobb＇s角由平均42．7^o矫正至平均9．3^o，畸形矫正率达到78．2％。随访过程中矫正的Cobb’s角平均增大1．6^o，无椎弓根切割，无神经损伤，没有发生植骨不愈合的病例，没有患者出现侧凸畸形。[结论]后路短节段椎弓根钉内固定加植骨融合矫正儿童先天性脊柱后凸，手术创伤小，短期效果可靠，但应严格掌握手术指征。     

King Ⅲ型特发性脊柱侧凸经胸侧前方椎体三维矫形术

[目的]探讨King Ⅲ型特发性脊柱侧凸经胸侧前方椎体三维矫形术的治疗效果。[方法]回顾本院2003年9月-2005年9月应用TSRH、CDH-M。等矫形器械对12例青少年King Ⅲ型特发性脊柱侧凸患者经凸侧胸腔于椎体侧前方行椎间松解、椎体三维矫形、植骨融合内固定术的临床资料，分析评价其手术并发症、侧凸矫正率及随访结果。[结果]术后出现肺部并发症2例，1例肺不张，1例呼吸道梗阻。经气管插管和呼吸机辅助呼吸后缓解。所有病例均未出现大血管损伤、脊髓损伤、肺炎和乳糜胸等并发症。术前胸椎Cobb’s角48^o～66^o，平均52．6^o。术后胸椎残余Cobb，s角平均15.2^o，矫正率77．8％。随访12～36个月，平均18．5个月。12例患者均获得了较好的节段性骨融合，矫正率无明显丢失，未发现假关节、内固定松动或断裂、失代偿等并发症。[结论]经胸椎体侧前方二维矫形手术是治疗King Ⅲ型特发性脊柱侧凸畸形的一种较安全、有效的内固定方式。     

特发性胸椎脊柱侧凸共平面矫形的原理与疗效

目的 探讨Coplanar(共平面)矫形技术在胸椎脊柱侧凸后路矫形中的应用及其矫形效果.方法 2008年6月至2009年3月,共27例脊柱侧凸患者接受一期后路CDH Legacy椎弓根螺钉固定加植骨融合手术,术中均采用Coplanar矫形技术,女26例,男1例;年龄11～23岁,平均15.9岁.均为特发性胸椎脊柱侧凸:Lenke 1AN型9例,1A-型2例,1BN型4例,1B-型5例,1CN型3例,1C-型2例,2AN型2例.术前Cobb角平均49°(40°～70°).术中在所有目标椎体置入椎弓根螺钉后,在胸椎主弯凸侧椎弓根螺钉上安装Coplanar延长杆,依次将两根Coplanar矫形棒插入延长杆顶部,此时侧凸已有一定矫形,两端使用压棒器械将矫形棒压向底端,所有椎弓根螺钉基本排列成一条直线,完成侧凸矫形;根据理想的胸椎后凸角度,在延长杆之间插入不同大小的Spacer;在胸椎主弯凹侧安装矫形棒,螺帽固定完毕后取出CoPlanar装置,再安装凸侧稳定棒,完成侧凸矫形.结果 术后Cobb角平均14°(6°～25°),矫正率为70.7%.手术前后胸椎后凸角度分别为18°和25°.手术时间210～300min,平均245 min;出血量600～2100ml,平均1500ml.平均随访15(12～18)个月,末次随访主弯矫正丢失3°,矫正丢失率为6.1%,无冠状面或矢状面失代偿.所有患者术后无须凸侧胸廓成形术,无死亡、感染及神经系统并发症发生.结论 Coplanar矫形技术可作为脊柱侧凸矫形的一个新选择,在获得良好冠状面矫形的同时,可获得良好的水平面去旋转和胸椎后凸维持.     

CD-Horizon器械在脊柱侧凸后路矫正中的应用

目的:探讨CD-Horizon(CDH)对脊柱侧凸后路矫形固定的效果。方法:应用CDH治疗各种脊柱侧凸63例,术前平均Cobb角65°。其中9例Cobb角90°以上的畸形及2例僵硬型畸形先行前路脊柱松解,术后Halo牵引2周再行后路CDH矫形固定融合术。结果:随访3~27个月,Cobb角术后平均21°,矫正率为67.7%。无死亡,无感染,无神经并发症。结论:CDH是具有多种矫正力的器械;CDH手术操作较简便,对各种复杂畸形的可操作性强,同时具有易拆除等特点。     

前路松解联合后路矫形固定治疗重度脊柱侧凸

目的：评价前路松解联合后路矫形对重度脊柱侧凸的治疗效果。方法：2000年7月至2007年1月采用前路松解联合后路矫形固定治疗重度脊柱侧凸23例,男12例,女11例;年龄9～18岁,平均15.3岁。其中先天性半椎体脊柱侧凸9例,特发性脊柱侧凸13例,神经纤维瘤病性脊柱侧凸1例。冠状面上Cobb角81°～126°,平均97.4°。结果：术后侧凸Cobb角为10°～55°,平均37.4°,平均矫正率56.2%。身高增加0.5～7.5cm,平均5.2cm。全部病例均获随访,时间6～24个月,平均10个月,2例出现交界区＂附加＂现象,无断棒、脱钩等并发症。结论：脊柱前路松解安全、有效,联合后路矫形内固定治疗重度脊柱侧凸可获得满意治疗效果。     

椎弓根螺钉固定能否较其他内固定对青少年特发性脊柱侧凸具有更强的后路矫形能力

有大量文献报道后路椎弓根螺钉固定治疗青少年特发性脊柱侧凸（AIS）能加强后路矫形能力。但这些报道均未考虑术前脊柱侧凸的柔韧性。在不考虑固定何种结构的情况下，僵硬的脊柱侧凸矫形程度显然差于柔软的脊柱侧凸。三个医疗中心回顾性队列研究72例Lenke1型AIS行后路矫形患者。在考虑术前脊柱柔韧性的前提下，作者比较了不同术式术后最初及术后两年的矫形程度。[第一段]     

后路椎体截骨内固定治疗僵硬性脊柱侧凸9例报告

[目的]评价后路椎体截骨矫形固定治疗僵硬性脊柱侧凸的临床疗效和适应证的选择。[方法]本院2003年4月~2005年2月采用后路顶椎楔形截骨矫形固定治疗9例僵硬性脊柱侧凸,男5例,女4例;年龄11~23岁,平均14.2岁。先天性侧凸5例,特发性侧凸4例。术前测Cobb s角平均为81.5°,悬吊后平均为67.2°,脊柱柔韧度平均11.5%。伴有神经症状2例,椎管内间隔2例。顶椎截骨平面在T8~11,截骨后采用Scofix器械固定,后路植骨融合。[结果]9例随访6~28个月,平均16.6个月。侧凸Cobb s角平均31.2°,矫正率平均61.3%,矫正丢失率平均2.1%。本组病例全部骨性融合,无断钉、断棒、松动。[结论]后路椎体截骨矫形固定治疗僵硬性脊柱侧凸,适用于中、重度青春期后特发性和重度先天性混合性脊柱侧凸畸形,此方法能一次性完成矫形侧凸,降低神经、血管损伤的发生率,并通过椎弓根系统固定和植骨融合重建脊柱的稳定性,临床疗效肯定。     

后路半椎体全切钉棒固定治疗幼儿和青少年先天性脊柱侧凸畸形的对比研究

[目的]评价后路半椎体切除钉棒固定术治疗婴幼儿青少年先天性脊柱侧后凸畸形的临床效果。[方法]回顾性分析施行后路半椎体切除术的先天性脊柱侧后凸16例幼儿和12例青少年患者的临床资料,均行后路一期半椎体切除及钉棒固定融合术。对手术时间、术中出血量及手术前后Cobb角进行了对比研究。[结果]幼儿组患者手术时间平均185 min;术中出血量平均375 ml,平均输血量450 ml;固定节段平均5.1个椎体。青少年组患者手术时间平均275 min;术中出血量平均765 ml,平均输血量850 ml;固定节段平均8个椎体。两组患者术后随访13²6个月,平均18.5个月。站立位全脊柱正侧位X线片示侧凸Cobb角幼儿组平均为12°,平均矫正率68.4%;终末随访时侧凸Cobb角平均17°,丢失5°,平均矫正率55.3%。青少年组侧凸Cobb角平均47°,平均矫正率13.0%;终末随访时侧凸Cobb角平均48°,丢失2°。幼儿组围手术期并发症包括伤口愈合不良1例,无神经系统并发症。青少年组伤口愈合不良2例,神经损害2例。[结论]后路半椎体切除可直接去除致畸因素,后路钉棒固定在幼儿组可获得良好的矫形。青少年组患者由于脊柱侧凸僵硬,矫形不佳,并且术后患者神经损害并发症较高。因此,对于先天性半椎体脊柱侧凸患者,幼儿期即行手术矫形,可以获得较佳的治疗效果。     

后路半椎体切除内固定矫治先天性脊柱侧后凸

目的评价后路一期半椎体切除椎弓根钉矫形治疗先天性半椎体所致脊柱侧后凸的临床效果。方法11例患者,平均年龄9.3岁,4例位于胸椎,5例位于腰椎,均为完全分节型,手术采用后路一期半椎体切除,椎弓根器械矫形并植骨融合。结果手术固定节段2-7个椎体,平均3.3个椎体。术后随访6-30个月,平均14.5个月。全脊柱正侧位X线片示冠状面Cobb角由术前平均41.15°矫正至15.35°,平均矫正率61.53％,矢状面Cobb角由术前平均34.15°矫正至13.26°,平均矫正率60.27％,顶椎偏移由术前25.34mm矫正至11.46mm,最后随访时侧凸和后凸Cobb角平均分别为16.86°和14.08°,与术后相比无纠正丢失。无任何手术并发症,无内固定断裂脱落,均融合。结论一期后路半椎体切除椎弓根器械矫形是治疗先天性脊柱侧后凸安全、有效的术式,能够获得满意的矫正。     

Cobb角与King分型对特发性脊柱侧凸高度损失手术纠正效果的影响

评价特发性脊柱侧凸脊柱畸形程度常采用 Cobb角方法 ,畸形外观的分型常采用 King分型 [1 ] 。作者设计的脊柱高度损失率方法反映脊柱在垂直高度方面的畸形程度 [3]。为了观察 Cobb角的大小、King分型对特发性脊柱侧凸脊柱高度损失的手术纠正效果的影响 ,作者做了如下工作。1　材料与方法1.1　临床资料　 1995 - 1999年行 Scofix法 [2 ] 矫形固定的特发性脊柱侧凸 2 6例 ,男 14例 ,女 12例。年龄 9～ 2 0岁 (平均13.8岁 )。均为一次手术矫正 ,即后路剃刀背切除、植入内植物矫形固定、脊柱植骨融合。依据术前 Cobb角分为四组 :A组 <6 0° 6…     

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.