斜外侧入路腰椎椎间融合术临床应用研究进展

<正>腰椎椎间融合术是治疗腰椎退行性疾病的有效术式,可在保持脊柱稳定性的基础上恢复椎间隙高度^[1],为非手术治疗无效的腰椎退行性疾病的首选治疗方式,经过长期的临床实践,证实疗效满意^[2]。斜外侧入路腰椎椎间融合术(OLIF)由Silvestre等^[3]于2012年在Mayer^[4]报道的微创前路椎间融合术的基础上形成。OLIF是近年常用的椎间融合术式之一,其通过腰大肌与腹部大血管之间的天然间隙建立通道,在直视下置入融合器,进行腰椎的间接减压与融合,不破坏肌肉和椎体小关节,具有手术创伤小、手术时间短、术中出血量少、术后恢复快等优点^[3,5]。     

椎旁肌影像学参数的评估及其与腰椎手术关系的研究进展

腰椎椎旁肌为附着于腰椎周围的多裂肌、竖脊肌、腰大肌及腰方肌等肌肉的总称,对于增加腰椎的稳定性有着重要作用[1],大多数腰椎手术会不同程度地损伤腰椎椎旁肌,椎旁肌受损可导致去神经支配的萎缩和脂肪浸润,造成腰椎失稳.有研究[2]表明,椎旁肌的退行性变与腰椎疾病及腰椎手术有一定的相关性.腰椎手术中椎旁肌破坏后易疲劳,对腰椎的...     

椎旁肌退变的影像学评价及其与腰椎疾病关系的研究进展

正腰椎周围的主要肌肉分为前后两群,前群主要包括腰大肌、腰小肌和腰方肌,后群主要为多裂肌、竖脊肌、半棘肌、回旋肌和横突间肌,竖脊肌又称为骶脊肌,包括髂肋肌、最长肌、棘肌,而目前针对腰部椎旁肌的研究主要集中在腰大肌、多裂肌和竖脊肌。椎旁肌对维持脊柱的稳定性起着重要作用,椎旁肌退变与多种腰椎疾病及术后并发症的发生发展存在相关性~([1])。影像学检测椎旁肌退变主要有三个征象:肌肉量(size)下降、放射图像密度下降及脂肪堆积增加~([2])。利用B超、CT和MRI等影像学技术研究椎旁肌     

不同影像学参数在评估腰部椎旁肌退变中应用的研究进展

椎旁肌是维持脊柱稳定和运动功能的重要结构之一,包括前群（腰大肌、腰小肌和腰方肌）和后群（多裂肌、竖脊肌、半棘肌、回旋肌和横突间肌）。椎旁肌退变的研究主要集中在多裂肌、竖脊肌和腰大肌退变,其与多种腰椎疾病及手术预后密切相关。椎旁肌退变包括肌肉数量（quantity）和肌肉质量（quality）两方面改变,主要以肌肉萎缩（肌纤维变细及减少,肌肉质量变小）和脂肪浸润（肌肉成分改变）的形式表现。随着影像技术不断发展,研究者可利用超声、CT和MRI等手段从不同角度描述椎旁肌退变,探究其在腰椎退行性疾病中的作用。已有大量研究报道了椎旁肌退变的影像学评估及其与腰椎疾病的关系,但是由于采用影像学参数不同、评价体系不统一,且受个体因素差异大,使得不同研究的结果难以比较[1~3]。目前该研究领域中最常用的影像学参数为椎旁肌横截面积（cross-sectional area,CSA）、肌肉密度（muscle density）及脂肪浸润（fat infiltration）,笔者将从这三方面以及新型影像学指标在评估腰部椎旁肌退变中的应用进行文献综述,比较各个影像学参数在相关研究中的适用范围、优势及不足。     

初发腰腿痛年轻人群中腰椎间盘退变与椎旁肌群改变的相关性

[目的]探寻腰椎间盘退变程度与腰椎旁肌肉群之间的关系。[方法]本研究包括患者组27例,为首次发生腰腿痛或未经过保守治疗的腰椎间盘突出症患者,平均年龄(22.33±1.64)岁;对照组25人,平均年龄(22.16±1.60)岁,为来院体检的健康人群。全部研究对象接受磁共振检查,按Pfirrmann标准对退变椎间盘进行分级,并在T2相上测量椎旁肌群与相应节段椎体间的横截面积比(MVr),脂肪浸润情况。[结果]患者组中的多裂肌群显著小于对照组(P=0.046),而最长肌、腰大肌在两组间无显著差异。患者组中的脂肪浸润等级显著高于对照组(P0.01)。在患者组中,脂肪浸润等级与椎间盘退变等级之间并不存在线性相关联系。椎旁肌群的MVr与椎间盘退变等级之间存在着中等的线性相关联系。[结论]腰椎多裂肌、最长肌、腰大肌与椎间盘突出程度之间存在着中等联系,其中多裂肌可能更为重要。椎间盘患者组中的腰椎旁肌群有更明显的脂肪浸润,然而脂肪浸润与椎间盘突出之间可能并不存在线性联系。     

L3椎旁肌群指数与骨质疏松症的相关性研究

目的 探讨L3椎旁肌群指数与骨密度(bone mineral density, BMD)的相关性以及如何将该指标运用于骨质疏松症的诊断。方法 回顾性分析2022年2月至2022年11月在江苏省第二中医院进行腰椎椎体CT平扫+重建及骨密度测定的符合入组标准的173名患者,采集患者L3椎体层面椎旁后肌群(多裂肌和竖脊肌)及腰大肌(椎旁前肌群)面积,计算出L3水平的椎旁肌群指数、腰大肌指数(psoas muscle index, PMI),并根据双能DXA骨密度仪测出的T值将其分为骨质疏松症组和非骨质疏松症组。采用Spearman等级相关分析椎旁肌群指数、PMI与BMD的相关性。用受试者工作特征(ROC)分析椎旁肌群指数和PMI预测骨质疏松症的有效性。结果 在BMD中,椎旁肌群指数与腰大肌指数均与其呈显著相关(椎旁肌群指数：L1 r=0.595,L2 r=0.549,L3 r=0.653,L4 r=0.661,L_1～4r=0.692,股骨颈r=0.575;腰大肌指数：L1 r=0.551,L2 r=0.508,L3 r=0.576,L4 r=0.569,L_1～...     

退行性腰椎滑脱治疗方法的研究进展

<正>退行性腰椎滑脱(degenerative spondylolisthesis,DS)是由于退行性变导致病变节段腰椎椎体相对于下位椎体发生移位,多见向前移位,且不伴有椎弓根断裂或缺损,也称为“假性滑脱”。退行性腰椎滑脱是发生于脊柱的临床常见病、多发病,好发于50岁以上的中老年人群,女性患病率更高。调查发现65岁以上老年人腰椎滑脱男女患病率分别为19.1%和25.0%,约1∶1.3^[1]。DS好发于L4/L5节段,其次为L3/L4和L5/S1节段,多以Ⅰ度、Ⅱ度轻度滑脱为主^[2-4]。目前,DS发病机制尚未完全清楚,可能与支持结构的年龄相关性退变有关,如椎间盘、关节突关节、骨、韧带、小关节囊和椎旁肌肉等。     

成人退行性脊柱侧凸患者椎旁肌和腰大肌退变的不对称性及其与脊柱-骨盆冠状位参数的关系

目的 :分析成人退行性脊柱侧凸(adult degenerative scoliosis,ADS)患者椎旁肌(多裂肌、竖脊肌)和腰大肌退变的不对称性及其与脊柱-骨盆冠状位参数之间的关系,为ADS患者冠状位失平衡的评估和预测提供新的思路。方法:回顾性分析96例ADS患者,测量并计算患者腰椎MRI顶椎层面椎旁肌和腰大肌的横截面积(cross-sectional area,CSA)、脂肪化比例(fat saturation fraction,FSF)、凹侧与凸侧横截面积之比(ratio of CSAconcave to CSAconvex,rCSA)、凹侧与凸侧脂肪化比例之比(ratio of FSFconcave to FSFconvex,r FSF),并在脊柱全长X线片上测量冠状位影像学参数,包括冠状位Cobb角(coronal Cobb angle,CA)和冠状面平衡距离(coronal balance distance,CBD)。根据C7铅垂线(C7PL)与骶骨中垂线(CSVL)的相对位置,将22例CBD≥30mm的患者分为两组:A组(C7PL在凸侧边,13例)和B组(C7PL在凹侧边,9例)。采用配对样本t检验分析顶椎层面凹凸两侧椎旁肌和腰大肌CSA和FSF的差异、Pearson相关分析肌肉影像学参数与脊柱-骨盆冠状位参数之间的相关性。结果:在顶椎层面,多裂肌、竖脊肌、腰大肌、椎旁肌凹侧CSA均显著大于凸侧(P0.05),多裂肌凹侧FSF显著大于凸侧(P0.01),竖脊肌凸侧FSF显著大于凹侧(P0.05),腰大肌、椎旁肌两侧FSF无统计学差异(P0.05)。CA与多裂肌凸侧CSA、竖脊肌和椎旁肌双侧CSA呈负相关(r=-0.233、-0.346、-0.211、-0.387、-0.232,P0.05),与多裂肌凹侧FSF、rCSA和椎旁肌r CSA呈正相关(r=0.360、0.424、0.259,P0.05)。A组CBD与各个肌肉的影像学参数均无相关性(P0.05)。B组CBD与竖脊肌凹侧CSA,腰大肌凹侧FSF,多裂肌、竖脊肌、腰大肌和椎旁肌r CSA,腰大肌rFSF呈正相关(r=0.720、0.768、0.720、0.752、0.738、0.721、0.893,P0.05)。结论:ADS患者椎旁肌和腰大肌影像学参数与脊柱-骨盆冠状位参数有明显的相关性,其中多裂肌rCSA与CA的相关性最强,在CBD超过30mm且C7PL在凹侧边的ADS患者中腰大肌r FSF与CBD的相关性最强,表明椎旁肌和腰大肌能体现ADS患者在冠状位失衡的严重程度。     

腰椎结核合并假性动脉瘤一例报道并文献复习

<正>脊柱结核是一种常见的肺外结核,多累及胸椎及腰椎,造成后凸畸形、神经功能障碍,也是非外伤性截瘫最常见的原因^[1]。腹主动脉瘤是指腹主动脉管壁呈瘤样扩张,直径大于3cm或大于正常值的50%。破裂性腹主动脉瘤是危及生命的急重症,其病死率为40%～90%^[2-3]。本次报道的患者考虑为腰椎结核伴椎旁脓肿,结核杆菌长期炎性侵蚀腹主动脉壁,导致腹主动脉瘤破裂,患者死亡。现将具体治疗过程作一报道,以提高同行对本病的认识,减少或杜绝此类事件发生。     

氨甲环酸在开放性脊柱融合手术中的应用研究进展

<正>氨甲环酸是一种赖氨酸类似物,它通过竞争性与纤溶酶原分子上的赖氨酸结合位点结合,阻止纤溶酶的形成,从而抑制纤维蛋白凝块的裂解,发挥其抗纤溶作用^[1-3]。开放性脊柱融合术的许多术式(如后路椎体间融合术)需要将椎旁肌剥离至横突以获得充分的手术视野;同时,手术过程中椎板减压及刮除椎体终板后会暴露较大面积的松质骨面^[4-5];而椎体为海绵状结构,具有丰富的血液供应,手术过程中及术后常常伴随着较多出血^[6]。大量出血会影响患者循环系统、凝血功能,并可导致许多相关并发症的发生^[7],而由此产生的异体输血存在发生血栓栓塞、感染、过敏等并发症的可能性^[8]。减少手术出血量有利于患者术后恢复,缩短住院时间,减轻患者经济负担,常见的方式包括缩短手术时间、术中及时止血、围手术期应用止血药物等^[9]。近年来,抗纤维蛋白溶解剂越来越多地用于减少出血和同种异体输血。其中,氨甲环酸是研究和使用最广泛的药物^[10]。但氨甲环酸在围手术期的应用途径和...     

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.