膝关节镜术后再次手术的原因

目的探讨膝关节镜术后再次手术的原因。方法对25例膝关节镜术后再次手术者行膝关节镜术16例,开放性滑膜切除术7例,全膝关节置换术2例。分析其再手术原因。结果软骨剥脱、滑膜病变残留或滑膜炎复发、漏诊半月板或交叉韧带损伤以及关节游离体是再手术中见到的主要病变。随访6个月-2年,16例膝关节镜术后机械性交锁症状均消失,7例行滑膜切除、2例人工全膝关节置换术者术后肿胀疼痛均消失。结论误漏诊、术前查体不细、适应证选择及手术处理不当是膝关节镜术后再次手术的主要原因。提高术前诊断水平、术中关节镜操作技术是减少再手术的关键。     

关节镜治疗膝关节弥漫色素沉着绒毛结节性滑膜炎

目的探讨关节镜下手术切除膝关节弥漫性色素沉着绒毛结节性滑膜炎的方法与疗效。方法2004年2月至2006年11月，对17例睬关节弥漫性色素沉着绒毛结节性滑膜炎，采用标准膝前内、外侧入路并辅以髌上外侧入路行关节镜下膝前间室滑膜全切，后内、外侧入路行膝后间室滑膜全切，并用射频治疗仪辅助清理十字韧带、关节软骨和半月板表面的滑膜，电凝止血。结果本组17例，4例流动人口失去联系，13例获得14-33个月，平均21．6个月随访。术后2个月，2例有轻度疼痛，2例有轻度肿胀，1例关节置换术后及1例开放手术后复发患者膝关节屈曲小于120°。术后1年，13例均无肿胀及积液，3例有轻度疼痛，2例膝关节屈曲仍小于120°，但不影响日常生活。采用Lysholm评分方法评定膝关节功能，术前Lysholm评分为（38．6±4．5）分。最后随访时，13例无一例复发，Lysholm评分为（87．3±5．6）分。结论关节镜下治疗膝关节弥漫性色素沉着绒毛结节性滑膜炎，具有手术切口小、组织损伤少、术后痛苦少、可早期进行功能锻炼、避免关节黏连引起的功能障碍等优点，且术中病变滑膜切除彻底，术后不易复发。该术式早中期疗效肯定，远期疗效有待进一步观察。     

膝骨性关节炎关节镜下清理术的指征及疗效

关节镜检查,对观察膝关节软骨面、半月板和滑膜病变的作用非常明确.在膝骨性关节炎的诊断中起着重要的作用但在治疗上存在着异议.尽管关节镜手术治疗膝骨性关节炎并不能都能取得满意疗效,但与截骨术、全膝置换相比,具有费用低、创伤小、恢复快、可重复、并发症少等优点.虽然关节镜手术不能阻止骨性关节炎的发展,但有些因素可预示手术疗效的好坏:①有膝内翻、膝外翻畸形的患者疗效差于没有畸形的;②短期机械性紊乱者明显优于慢性持续疼痛者;③已经历过一次关节镜手术的疗效差于初次接受关节镜手术者;④在退变早期阶段进行手术疗效明显优于晚期阶段.     

射频汽化仪在膝关节镜手术中的应用

目的探讨射频汽化仪在膝关节镜手术中的应用及其疗效。方法利用射频汽化仪对78例不同膝关节疾病患者进行关节镜手术,其中半月板部分切除18例,全切除7例,盘状半月板成形13例,损伤软骨及韧带修整21例,滑膜切除6例,髌骨外侧支持带松解5例,胫骨髁间隆突骨折固定6例,前交叉韧带重建2例。结果术后患侧膝关节肿胀轻,未见明显关节积液、积血。随访3～12个月,75例患者自觉症状良好,关节绞锁、疼痛等症状缓解;3例重度骨性关节炎者症状无缓解,转行人工关节置换术。膝关节功能评定：优46例,良29例,可0例,差3例,优良率96．2％。结论射频汽化仪具有良好的低温切除、止血作用,使用方便,有助于提高膝关节镜手术的效率及疗效。     

跨膝关节后纵隔入路的建立及临床应用

目的 探讨跨膝关节后纵隔入路（ATS）的建立方法及临床应用效果。方法 10具新鲜防腐膝关节标本进行后纵隔的大体解剖,65例行后室关节镜镜下观察,包括类风湿关节炎、色素绒毛结节性滑膜炎、骨性关节炎、后室游离体或异物、后交叉韧带（PCL）损伤或撕脱骨折、半月板后角损伤、不明原因关节肿痛积液、剥脱性骨软骨炎、化脓性关节炎、痛风。2002年1月—2005年6月,我们共采用ATS入路进行关节镜检查和治疗22例。先建立前外侧入路,关节镜监视下建立后外侧入路。同法建立前内侧与后内侧入路。把关节镜置于后内侧入路,从前内侧入路进入刨刀逐步刨除PCL表面的滑膜组织,再把关节镜置于前内侧入路,从后内侧入路引入钝头转换棒,指向PCL后缘中份处的后纵隔,向外侧轻柔地推顶后纵隔。把关节镜置于后外侧入路,镜视下引导穿出钝头转换棒建立ATS。结果后纵隔位于膝关节后室正中,在矢状面上呈幕布状,在横断面上呈三明治样结构。关节镜下见后纵隔表面被覆盖滑膜组织。22例均成功建立ATS入路,占同期膝关节后室治疗的34％（22／65）。行膝关节后室滑膜切除术7例,游离体取出6例,PCL重建术4例,PCL撕脱骨折复位固定2例。骨性关节炎6例中,分别行镜下软骨成形、炎性滑膜切除、半月板成形术。所有病例均未发生血管神经损伤。所有病例临床随访4～45个月,平均20个月,9例患者仍有轻微疼痛或关节肿胀,2例患者疼痛剧烈,已推荐行全膝关节置换术,其余11例患者未见关节肿痛症状复发。结论 ATS入路在镜下视野无盲区,能够跨后纵隔进行手术操作,是一种安全有效诊治膝关节后室疾病的方法。从内侧向外侧建立ATS比较可靠,后交叉韧带可以作为建立ATS时的内标志物。     

膝关节弥漫性色素沉着绒毛结节性滑膜炎的关节镜治疗

目的探讨采用关节镜技术治疗膝关节弥漫性色素沉着绒毛结节性滑膜炎的方法及其临床效果。方法1999年1月～2001年12月,对32例膝关节弥漫性色素沉着绒毛结节性滑膜炎,在常规关节镜入路的基础上,结合膝关节后内侧、后外侧和跨后纵隔入路,进行滑膜全切。手术时强调对膝关节后内侧室和后外侧室病变滑膜的彻底切除,同时通过辅助切口切除关节外病变组织。术后进行系统的康复训练。通过13～47个月的随访,了解患膝疼痛、肿胀、活动度以及患肢整体功能康复情况。结果术后1年,2例有轻微疼痛,1例有轻度肿胀,均无关节积液;膝关节活动度平均为143°±5.1°。最后随访时,23例行MR检查,1例在内侧半月板后角底面与胫骨平台之间的憩室内发现复发,影像学复发率为4.35%(1/23),但患者无主观症状;其余患者在MRI上无复发现象。术前国际膝关节评分委员会(IKDC)膝关节功能主观评分为(63.4±5.1)分,Lysholm膝关节功能评分为(35.6±4.7)分。最后随访时,IKDC膝关节功能主观评分为(87.9±4.9)分,Lysholm膝关节功能评分为(86.3±5.6)分。3例患者因前十字韧带功能不全,于滑膜切除术后3～5个月进行了前十字韧带重建术。结论通过关节镜能够完成膝关节弥漫性色素沉着绒毛结节性滑膜炎的滑膜彻底切除,有助于滑膜炎的治疗。关节镜手术创伤小,     

膝关节骨性关节炎镜下半月板损伤特征与微创治疗的临床研究

目的探讨膝关节骨性关节炎镜下半月板特征及其对微创手术治疗的指导意义。方法根据关节镜下半月板损伤及其对周围滑膜、关节软骨的影响程度分为4型:Ⅰ型,半月板局限性损伤;Ⅱ型,局限性损伤合并磨损性损伤;Ⅲ型,损伤涉及半月板大部甚至整体,半月板松动;Ⅳ型,半月板磨损合并部分或大部缺如。各型损伤均采用相对应的镜下半月板手术治疗。结果Ⅰ型半月板损伤10例,Ⅱ型20例,Ⅲ型27例,Ⅳ型11例。Ⅰ型损伤:4例行缝合修复手术,6例行镜下半月板部分切除术;Ⅱ型:镜下部分切除18例,次全切除2例;Ⅲ型:清理刨削1例,镜下部分切除5例,次全切除16例,全切除5例;Ⅳ型:次全切除2例,全切除9例。随访平均22个月(6~52个月),劳累后痛7例(Ⅱ型1例,Ⅲ型2例,Ⅳ型4例);绞锁1例(Ⅲ型);关节屈曲受限2例(Ⅲ型1例,Ⅳ型1例)。3例(Ⅲ型2例、Ⅳ型1例)术后2~3年行全膝关节置换术,其余65例Lysholm评分:术前50±12,术后随访时85±8(t=3.521,P<0.01)。结论膝关节骨性关节炎半月板损伤具有一定的镜下特征。膝关节骨性关节炎半月板损伤的镜下分型有助于指导镜下手术,提高膝关节骨性关节炎微创手术治疗的效果。     

骨病

全膝关节表面置换术治疗膝骨性关节炎；急性膝关节痛风性关节炎关节镜下诊断与治疗；人工全膝关节表面置换治疗骨关节疾病52例；镜下清理、刨削、髌外侧减压术治疗膝关节骨性关节炎     

2000ArthroCare System在膝关节镜手术中的应用

目的探讨冷融化技术在膝关节镜手术中方法和前景。方法采用2000ArthroCare System(2000ACS)对221例膝关节病实施手术治疗。关节镜下疾病诊断：骨性关节炎73例，半月板损伤49例，关节软骨软化症29例，滑膜皱襞综合征15例，盘状半月板13例，滑膜炎11例，大骨节病11例，ACL 8例，剥脱性骨软骨炎5例，关节粘连5例，TKA术后松解2例。通过2000ACS做关节镜下的半月板切除、成形，软骨面及韧带修整，滑膜切除，髌外侧支持带松解术等。结果按Lysholm评分，术前平均43．92，术后3个月81．96，术后6个月92．06。结论关节镜2000ACS治疗关节疾病，操作安全，疗效可靠，痛苦少，有利于早期功能锻炼。     

膝关节髌下皱襞的临床意义

目的:观察膝关节镜下髌下皱襞结构的变化,探讨膝关节髌下皱襞的临床意义。方法:回顾性总结分析膝关节镜手术病例400例,男177例,女223例;年龄9~79岁,平均42岁。术前均有膝关节疼痛、肿胀和交锁等现象,保守治疗无效,行膝关节镜检查及镜下手术。术中证实单纯的髌下皱襞病变11例,术前有膝前区疼痛症状者8例,疼痛区域模糊不定者3例,膝关节反复肿胀、积液者2例;术前诊断为半月板损伤4例,关节软骨损伤2例,髌股关节骨性关节炎1例,髌下脂肪垫损伤4例。11例均行膝关节镜下髌下皱襞切除术。结果:400例膝关节镜手术中发现有髌下皱襞结构的284例(71%);有髌下皱襞病变的52例(13%),其中单纯的髌下皱襞病变11例(2.75%)。髌下皱襞病变镜下表现为髌下皱襞肿胀、增厚、纤维化、丧失弹性,与髁间凹产生撞击。11例单纯髌下皱襞病变均行关节镜下髌下皱襞切除术,术后随访9例,2例失访,随访时间3~24个月,平均14个月。疗效评定优7例,良1例,可1例,差0例,优良率88.89%。结论:髌下皱襞具有明确的临床意义,其病变可以引起临床症状。     

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.