关节镜下应用RIGIDfix和Intrafix系统固定自体4股胭绳肌重建前交叉韧带

[目的]探讨关节镜下应用RIGIDfix和Intrafix系统固定自体4股胭绳肌重建前交叉韧带的临床效果.[方法]对36例前交叉韧带断裂的患者,在关节镜下采用4股胭绳肌肌腱行前交叉韧带重建,应用RIGIDfix和Intrafix系统对移植物进行固定,术后进行系统的康复治疗并处理相关的并发症.术后随访6～12个月,询问患者的主观症状,并对患者进行膝关节活动度、前抽屉试验、Lachman试验和轴移试验等检查,按照Lysholm膝关节评分标准评价疗效.[结果]本组病例均未发生严重并发症,术后进行6～12个月的随访,所有患者均已返回工作岗位,膝关节屈曲均达到130°,伸直达到0°,有3例在激烈活动时有时会感觉到膝关节打软不稳,其余病例均无打软不稳的感觉.随访时前抽屉试验35例阴性,1例阳性;Lachman试验33例阴性,3例阳性;轴移试验均为阴性.按照Lysholm膝关节评分标准,评分从51.3±4.2分提高至85.6±4.6分,差异有显著性意义(P＜0.01).[结论]关节镜下应用RIGIDfix和Intrafix系统固定自体4股胭绳肌肌腱重建前交叉韧带是治疗前交叉韧带损伤的一种较好方法,具有手术操作简单、固定牢固、愈合率高等优点.     

关节镜下应用Rigidfix和Intrafix系统固定重建前交叉韧带

目的探讨关节镜下应用Rigidfix和Intrafix系统固定自体4股腘绳肌单束重建前交叉韧带临床效果。方法40例前交叉韧带断裂患者在关节镜下均采用4股腘绳肌肌腱单束重建前交叉韧带,术后进行系统的康复治疗。结果40例随访6～12个月,均未发生严重并发症,膝关节屈曲均达到130°,伸直达到0°。随访时前抽屉试验35例阴性,5例Ⅰ度阳性;Lachman试验37为阴性,3例Ⅰ度阳性;轴移试验均为阴性。所有患者均无膝关节不稳的主观症状。按照Lysholm膝关节评分标准：平均评分从（40．3±4．2）分提高至（90．4±3．6）分,差异有显著性（P〈0．01）：结论关节镜下4股自体腘肌腱重建前交叉韧带应用Rigidfix和Intrafix系统固定是一种较好方法,具有手术操作简单、固定牢固、愈合率高等优点.     

关节镜下采用腘绳肌肌腱指骨钢板悬吊固定重建前交叉韧带

[目的]探讨关节镜下采用腘绳肌肌腱指骨钢板悬吊固定法重建前交叉韧带(ACL)的临床效果。[方法]对13例前交叉韧带断裂的患者,在关节镜下采用6~8股腘绳肌肌腱进行单束双隧道重建,4孔指骨钢板对移植物行悬吊式固定。术后1 a随访,并按照Lysholm膝关节评分标准评价疗效。[结果]12例患者(92.31%)Lachm an试验阴性,1例患者Lachm an试验阳性,12例患者轴移试验阴性,1例患者阳性。按照Lysholm膝关节评分标准,评分从47.77±1.96提高至95.38±4.74,差异有显著性意义(P<0.01)。[结论]关节镜下采用腘绳肌肌腱指骨钢板悬吊固定重建前交叉韧带是恢复膝关节稳定性的可靠方法。     

关节镜下采用6～8股腘绳肌腱单束重建前交叉韧带

目的:探讨关节镜下采用6-8股腘绳肌肌腱单束重建前交叉韧带对恢复膝关节稳定性的临床效果。方法:前交叉韧带损伤患者14例,男9例,女5例;年龄19-51岁,平均32.8岁;病程1-22个月,平均3.7个月。Lachman试验:阳性伴软性终止点12例,阳性伴硬性终止点2例;前抽屉试验:阳性伴软性终止点12例,阳性伴硬性终止点2例;轴移试验阳性12例。合并I度膝关节外翻不稳1例。在关节镜下采用6-8股腘绳肌肌腱单束重建,4孔指骨钢板对移植物行悬吊式固定。结果:术后1年随访,13例患者Lachman试验阴性,1例患者Lachman试验阳性,13例患者轴移试验阴性,1例患者阳性。按照Lysholm膝关节评分标准,评分从术前平均(47.71±1.98)分提高至术后平均(95.36±4.73)分,差异有显著性意义(P<0.01)。结论:关节镜下采用6-8股腘绳肌肌腱单束重建前交叉韧带是恢复膝关节稳定性的可靠方法,具有切口小,对伸膝装置无干扰等优点。     

关节镜下应用钮扣式钢板固定四股自体股腘绳肌腱重建前交叉韧带

目的 探讨关节镜下应用钮扣式钢板固定四股自体腘绳肌腱重建膝关节前交叉韧带（anterior cruciate ligament,ACL）的临床疗效. 方法 对32例前交叉韧带损伤者在关节镜下应用钮扣式钢板固定四股腘绳肌腱重建术.术前和术后进行Lachman试验、轴移试验评估膝关节的稳定性,用Lysholm评分法评价膝关节功能.术前常规行MRI及膝关节正侧位、髌骨轴位X线片检查,排除前交叉韧带起止点骨性撕脱. 结果 32例随访3.5～29个月,其中25例＞12个月.所有病例膝关节不稳定感明显改善.术前Lachman试验阳性32例,轴移试验阳性28例.Lysholm综合评分51.8±5.6.术后Lachman试验30例阴性,2例弱阳性,轴移试验均为阴性,膝关节功能Lysholm综合评分为90.7±2.5.3例关节积液,经关节穿刺抽吸后吸收. 结论 关节镜下应用钮扣式钢板固定四股自体腘绳肌腱重建膝ACL的近期临床疗效良好.     

关节镜下应用Rigidfix与Intrafix系统固定异体肌腱重建前交叉韧带

目的 探讨关节镜下应用Rigidfix与Intrafix系统固定同种异体胫前肌肌腱重建前交叉韧带(ACL)的临床效果. 方法自2003年3月至2006年9月对56例在关节镜下确诊ACL断裂的患者采用深低温同种异体胫前肌肌腱进行韧带重建,应用Rigidfix与Intrafix系统对移植物进行固定,术后进行系统康复训练.随访观察患者的主观症状,并检查患膝关节活动度、前抽屉试验、Lachman试验和轴移试验,按照Lysholm膝关节评分标准评价疗效.结果 所有患者随访1.5～5.0年,平均2.3年.有2例患者在剧烈活动时伴有错动感,末次随访时膝关节活动度均可达到伸-5°～0°,屈120°～130°,前抽屉试验、Lachman试验及轴移试验均为阴性,Lysholm膝关节评分由术前(48.2±5.3)分提高至术后(91.1±4.2)分,差异有统计学意义(P<0.05).结论 关节镜下应用Rigidfix与Intrafix系统固定同种异体胫前肌肌腱重建ACL可获得满意的临床疗效.     

关节镜下应用EndoPearl和Intrafix固定腘绳肌肌腱重建前交叉韧带

目的 关节镜下采用腘绳肌肌腱和EndoPearl与Intrafix重建前交叉韧带.方法 31例前交叉韧带断裂患者在关节镜下采用四股腘绳肌肌腱重建前交叉韧带,股骨端应用EndoPearl和可吸收界面螺钉固定,胫骨端应用Intrafix固定,术后系统康复.结果 全部获随访,平均15.5个月(12～20个月).术前Lysholm评分平均为(54.2±5.4)分,术后为(98.4±0.2)分.与术前相比差异有显著性意义(P＜0.05).结论 关节镜下采用腘绳肌肌腱和EndoPearl与Intrafix重建前交叉韧带操作简单,固定可靠,疗效肯定.     

关节镜下应用EndoPearl与Intrafix固定双侧绳肌肌腱一期重建膝关节前后交叉韧带

目的探讨关节镜下应用EndoPearl与Intrafix固定双侧腘绳肌肌腱同时重建膝关节前后交叉韧带的近期临床效果。方法对2004年6月~2005年3月收治的10例膝关节前后交叉韧带同时断裂的患者,切取双侧腘绳肌腱,2条半腱肌腱和2条股薄肌腱分别对折成四束,折端固定同直径EndoPearl。关节镜下利用两组移植物同时分别重建膝前后交叉韧带。股骨端应用可吸收界面螺钉顶压固定EndoPearl与移植肌腱,胫骨端应用Intrafix固定四束肌腱。结果10例均获得随访,平均7.5个月(6~15个月),切口Ⅰ期愈合,无感染。其中新鲜损伤4例,陈旧性损伤6例,合并后外侧复合体损伤3例,均予同期修复,合并内侧副韧损伤6例,未予特殊处理,5例曾急诊修复腘动静脉。术后3个月膝关节活动范围均超过120°,无伸膝受限,后抽屉试验Ⅰ度阳性2例,其余为阴性;Lyshlom评分(92.6±3.2)分。结论关节镜下应用EndoPearl与Intrafix固定双侧腘绳肌肌腱同时重建膝关节前后交叉韧带方法确切,可有效恢复膝关节功能。     

关节镜下应用EndoPearl与Intrafix固定双侧腘绳肌肌腱一期重建膝关节前后交叉韧带

目的 探讨关节镜下应用EndoPearl与Intrafix固定双侧腘绳肌肌腱同时重建膝关节前后交叉韧带的近期临床效果.方法 对2004年6月～2005年3月收治的10例膝关节前后交叉韧带同时断裂的患者,切取双侧腘绳肌腱,2条半腱肌腱和2条股薄肌腱分别对折成四束,折端固定同直径EndoPearl.关节镜下利用两组移植物同时分别重建膝前后交叉韧带.股骨端应用可吸收界面螺钉顶压固定EndoPearl与移植肌腱,胫骨端应用Intrafix固定四束肌腱.结果 10例均获得随访,平均7.5个月(6～15个月),切口Ⅰ期愈合,无感染.其中新鲜损伤4例,陈旧性损伤6例,合并后外侧复合体损伤3例,均予同期修复,合并内侧副韧损伤6例,未予特殊处理,5例曾急诊修复腘动静脉.术后3个月膝关节活动范围均超过120°,无伸膝受限,后抽屉试验Ⅰ度阳性2例,其余为阴性;Lyshlom评分(92.6±3.2)分.结论 关节镜下应用EndoPearl与Intrafix固定双侧腘绳肌肌腱同时重建膝关节前后交叉韧带方法确切,可有效恢复膝关节功能.     

关节镜下自体胭绳肌腱重建前交叉韧带应用Rigidfix和Intrafix系统固定的价值

目的 探讨关节镜下自体胭绳肌肌腱单束重建前交叉韧带(ACL)时应用Rigidfix和Intrafix系统固定的临床效果.方法 2004年6月至2007年10月,40例ACL断裂的患者均在关节镜下采用4股胭绳肌肌腱单束重建ACL,股骨端移植物应用Rigidfix系统固定,胫骨端移植物应用Intrafix系统固定,术后进行系统的康复治疗.结果 所有患者均未发生严重并发症,术后进行6～12个月随访,膝关节屈曲均达到130°,伸直达到0°,随访时前抽屉试验35例阴性,5例Ⅰ度阳性,Lachman试验37例阴性,3例Ⅰ度阳性,轴移试验均为阴性,所有患者均无膝关节不稳的主观症状.术前及随访时前抽屉试验阳性率比较(100% vs.12.5%),差异有统计学意义(χ2=58.72,P＜0.01);术前及随访时轴移试验阳性率比较(82.5% vs.0),差异有统计学意义(χ2=52.82,P＜0.01).按照Lysholm膝关节评分标准,评分从(40.3±4.2)分提高至(90.4±3.6)分,差异有统计学意义(t=3.852,P＜0.01).结论 关节镜下自体胭绳肌肌腱重建ACL时应用Rigidfix和Intrafix系统固定是一种较好的方法,具有手术操作简单、固定牢固、愈合率高等优点,值得推广应用.     

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.