脊柱活动节段脊索瘤的外科治疗及其预后(附15例报告)

[目的]探讨脊柱活动节段脊索瘤外科治疗方式与疗效。[方法]对接受手术治疗的15例脊柱活动节段脊索瘤病人的临床资料进行回顾性分析。根据肿瘤WBB（Weinstein-Boriani-Biagini）分期，肿瘤主要位于椎体范围内，即4～9扇区内7例，累及椎体且超过一侧4扇区或9扇区4例，同时超过两侧4扇区和9扇区4例；肿瘤侵及A-D层13例，A—C层2例；单椎节骨质破坏9例，2个椎节骨质破坏5例，累及3个椎节1例。手术行椎体或矢状切除10例，全脊椎切除5例。后路重建4例（4例病灶均位于上颈椎），前路重建3例，前后联合重建8例。术中取大块自体骨（髂骨或肋骨）或钛网＋植骨块融合9例，钛网＋骨水泥填塞支撑6例。术后均辅以瘤灶局部放疗。[结果]患者术后临床症状改善明显，神经功能恢复满意，植骨融合率100％。随访14～123个月，平均56．2个月，局部复发7例，死亡4例，未见远处转移病例。[结论]脊柱活动节段脊索瘤临床发病较少，早期症状不典型。应注重肿瘤的早期诊断与治疗。手术切除是治疗脊柱脊索瘤的主要手段，全脊椎切除能明显降低复发率。术后辅助以肿瘤病灶局部放疗对抑制肿瘤复发或进展有积极作用。     

颈椎骨巨细胞瘤手术治疗的中长期随访及预后分析

目的探讨颈椎骨巨细胞瘤（GCT）的临床特点、肿瘤切除方式及预后。方法手术治疗23例颈椎GCT，依据脊柱肿瘤WBB分期，采取椎体次全切除3例，矢状位切除5例，附件切除1例，全脊椎切除14例。脊柱重建方式采取单纯自体髂骨植骨和颈前路钛板、钛网植骨内固定或前后联合内固定加植骨融合。18例患者术后配合局部放疗。结果1例C1-2椎体、附件GCT患者在术后出现神经症状加重，术后10d因呼吸、循环系统衰竭死亡。22例获得3年～10年4个月的随访，患者术后颈部疼痛症状消失，神经根刺激症状得到不同程度的缓解，术后3个月患者神经功能Frankel分级，平均有1—2个级别的改善。植骨全部融合。内固定融合良好，未见脊椎失稳现象。椎体次全切除组复发3例；矢状位切除复发2例，而全脊椎切除组仅1例于术后4年复发。随访期内死亡4例，均为复发病例，1例行翻修手术后6个月出现肺部转移，13个月时死于肺部感染；另有3例均因肿瘤复发最终导致高位瘫痪、全身器官衰竭死亡。结论颈椎GCT是一种良性侵袭性或低度恶性肿瘤，手术治疗应在尽可能保留神经功能的前提下实施扩大范围的肿瘤切除术。全脊椎切除结合术后辅助放疗能明显降低局部复发率。     

前、后联合入路全脊椎切除附加内固定治疗颈椎骨肿瘤39例报告

目的探讨对颈椎骨肿瘤采用前后联合入路全脊椎切除、内固定重建技术的疗效及其预后。方法1998年10月至2003年10月,对39例颈椎(C3-7)骨肿瘤患者实施全脊柱切除术。其中原发性骨肿瘤34例,包括骨巨细胞瘤14例,浆细胞瘤6例,神经鞘瘤(侵及椎体)1例,软骨肉瘤4例,骨母细胞瘤4例,恶性神经鞘瘤2例,动脉瘤样骨囊肿2例,脊索瘤1例;转移性肿瘤5例,原发灶来源于甲状腺癌、前列腺癌各2例,肺癌1例。经前后联合入路行单椎节切除29例、双椎节切除7例、3个椎节切除3例。经一期或二期前后联合入路行肿瘤切除与内固定重建。前路采用钛网植骨加AO、Orion、Zephir或者Codman等带锁钢板内固定,后路Cervifix、AXIS内固定重建。结果术后随访6个月至5年,绝大多数患者术后近期疗效较满意,局部疼痛和神经症状均有不同程度改善或缓解,19例脊髓神经功能完全恢复。1例术后出现一过性瘫痪加重,1例恶性神经鞘瘤术后1年局部复发,1例转移癌患者于术后25个月因全身衰竭死亡。结论全脊椎切除能显著降低颈椎原发性骨肿瘤局部复发率,改善脊髓神经功能,提高手术疗效。     

骶骨肿瘤的手术治疗

目的：探讨骶骨肿瘤的手术治疗方法及其疗效。方法：15例骶骨肿瘤患者,男12例,女3例;年龄17～68岁,平均54.6岁。原发性肿瘤10例,转移性肿瘤5例。采用前方入路病灶清除5例,后方入路单纯病灶清除3例,病灶清除联合植骨加钉棒系统内固定重建7例。术后根据肿瘤性质辅助放疗或化疗。结果：13例获随访,时间4个月～5年,所有患者近期疗效满意,局部疼痛及神经症状均有不同程度的改善。1例术后出现二便功能障碍加重,经保守对症治疗4个月后好转。1例脊索瘤和2例转移瘤于术后1～2年死于复发和远处转移。1例骨巨细胞瘤于术后6个月局部复发,未再手术。结论：根据骶骨肿瘤患者特点制定个体化的以手术治疗为主的综合治疗方案,能得到较满意疗效。     

脊柱肿瘤的手术治疗

目的 :探讨对于脊柱肿瘤一期全脊椎切除及脊柱稳定性重建的手术方法和临床效果。方法 :对 12例脊柱肿瘤行前、后路或前、后联合入路Ⅰ期全脊椎切除、脊髓减压 ,椎间植骨融合、内固定术。结果 :术后 11例获得随访 ,按照Frankel分级较术前均有 1级以上提高 ,所有患者局部疼痛症状消失。术后复查平均植骨融合时间 3个月。1例脊索瘤术后 1年复发 ,1例巨细胞瘤术后 9个月复发。结论 :针对脊柱肿瘤的性质、部位 ,通过不同的手术入路行一期全脊椎切除、植骨融合内固定 ,彻底切除肿瘤 ,重建脊柱稳定性并体现了个体化的治疗方向     

胸腰椎恶性肿瘤的外科分区及手术治疗

目的：探讨在WBB分区指导下的病椎切除术在胸腰椎恶性肿瘤外科治疗中的临床应用。方法：对我院自2002年3月～2006年3月收治的42例胸腰椎恶性脊柱肿瘤患者的病历资料进行回顾性分析，其中骨髓瘤4例，骨巨细胞瘤9例，脊索瘤2例，骨转移瘤27例。行椎板减压姑息性手术治疗5例，行椎体及附件病灶刮除手术治疗13例，行椎体附件肿瘤切除术7例，行全椎体切除术治疗11例，行一期后路或前、后联合入路全脊椎切除手术治疗6例。结果：36例（85．7％）患者术后腰背部疼痛症状减轻或消失，20例（47．6％）患者术后神经功能得到改善。病灶刮除的13例患者中有5例分别于术后第3、6和12个月复诊时发现局部复发，接受二次手术治疗。本组病例术中、术后无严重并发症发生，全脊椎切除的6例患者截至最近随访时，未发现肿瘤复发，植骨融合，内固定稳定。结论：根据WBB分区系统完成的胸腰椎恶性肿瘤手术治疗策略，特别是全脊椎切除术是治疗恶性脊柱肿瘤的一种有效外科手段。     

脊柱肿瘤的全脊椎切除术及脊柱稳定性重建

目的探讨对脊柱肿瘤行全脊椎切除术的可行性与临床价值,以及重建脊柱稳定性的可靠方法。方法对27例椎体和附件结构均遭破坏的脊柱肿瘤采用全脊椎切除及内固定重建技术进行治疗,其中包括上颈椎至下腰椎的良、恶性及转移性肿瘤,手术切除1～3节脊椎。结果23例获完整随访,随访时间7～96个月(平均25个月)。1例L5恶性神经纤维瘤及1例C6,7巨细胞瘤于术后10个月及12个月复发,患者放弃治疗;1例C2～4脊索瘤术后1年复发,再次手术效果良好;其余20例未见复发。25例术前伴神经功能损害者,术后有23例获显著改善。结论全脊椎切除术为治疗全脊椎受累脊柱肿瘤的有效方法;切除1～3节脊椎的脊柱可由相应内固定系统进行可靠的稳定性重建。     

骶骨脊索瘤的临床特点及综合治疗

目的介绍骶骨脊索瘤的临床特点并对其综合治疗的疗效和相关问题进行分析。方法对1999年12月~2006年12月收治的行以手术切除为主的综合治疗的40例骶骨脊索瘤病例进行回顾性分析。结果本组病例无术中死亡,术后肿瘤局部复发13例,复发率为32.5%,其中3例复发2次;发生肺部转移2例,转移发生率为5%。术后5年内共5例死亡,患者经过综合治疗后的术后5年生存率达87.5%。结论以手术切除为主、辅以术中化疗、术后放疗的综合治疗方法,对降低骶骨脊索瘤的局部复发率、延长患者生存期、提高患者生活质量有重要作用,是治疗骶骨脊索瘤的有效方法。     

胸腰椎脊索瘤的临床特点和治疗分析

目的:探讨胸、腰椎脊索瘤的临床特点和治疗方法。方法:对7例胸、腰椎脊索瘤患者的临床资料进行总结,根据WBB分期,实施椎体或全脊椎切除,其中囊内切除3例、扩大切除4例。结果:术后5例患者症状完全消失。1例T7、T8脊索瘤患者出现切口下缘顽固性疼痛,封闭后疼痛减轻。1例L1~L3脊索瘤全瘫患者,双下肢肌力恢复至2级。病理检查镜下均可见“印章样细胞环”和“合胞体”。术后平均随访5.2年,局部复发1例,无远处转移。结论:胸腰椎脊索瘤相对少见,临床表现不典型,容易误诊。“印章样细胞环”和“合胞体”是胸、腰椎脊索瘤的典型病理表现。全脊椎切除肿瘤能降低局部复发率。     

胸腰椎恶性肿瘤的外科分区及手术治疗

目的：探讨在WBB分区指导下的病椎切除术在胸腰椎恶性肿瘤外科治疗中的临床应用。方法：对我院自2002年3月～2006年3月收治的42例胸腰椎恶性脊柱肿瘤患者的病历资料进行回顾性分析,其中骨髓瘤4例,骨巨细胞瘤9例,脊索瘤2例,骨转移瘤27例。行椎板减压姑息性手术治疗5例,行椎体及附件病灶刮除手术治疗13例,行椎体附件肿瘤切除术7例,行全椎体切除术治疗11例,行一期后路或前、后联合入路全脊椎切除手术治疗6例。结果：36例（85．7％）患者术后腰背部疼痛症状减轻或消失,20例（47．6％）患者术后神经功能得到改善。病灶刮除的13例患者中有5例分别于术后第3、6和12个月复诊时发现局部复发,接受二次手术治疗。本组病例术中、术后无严重并发症发生,全脊椎切除的6例患者截至最近随访时,未发现肿瘤复发,植骨融合,内固定稳定。结论：根据WBB分区系统完成的胸腰椎恶性肿瘤手术治疗策略,特别是全脊椎切除术是治疗恶性脊柱肿瘤的一种有效外科手段。     

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.