腰椎椎间隙高度与上位椎体高度的比值与椎间盘退行性变Pfirrmann分级的相关性

目的 探讨腰椎椎间隙高度与上位椎体高度的比值与椎间盘退行性变程度之间的关系,为腰椎椎间盘退行性疾病的诊断和治疗提供客观准确的依据。方法 回顾性分析2019年1月—2019年6月来本院就诊的61例腰椎椎间盘退行性变患者临床资料。在腰椎侧位X线片上测量腰椎椎间隙及相应上位椎体的高度,并计算椎间隙高度与上位椎体高度的比值;在腰椎矢状位MRI上评估腰椎椎间盘退行性变Pfirrmann分级;比较不同Pfirrmann分级椎间盘的椎间隙高度与上位椎体高度比值的差异,并采用Spearman相关分析研究椎间隙高度与上位椎体高度比值与相应节段椎间盘Pfirrmann分级之间的相关性。结果 除L₁/L₂节段,其余各节段椎间隙高度与上位椎体高度比值均随着Pfirrmann分级增加而逐渐减小,差异均有统计学意义（P < 0.05）。相同Pfirrmann分级的不同节段椎间盘之间椎间隙高度与上位椎体高度比值差异无统计学意义（P > 0.05）。Spearman相关分析结果显示,L₂/L₃、L₃/L₄、L₄/L₅、L₅/S₁节段Pfirrmann分级与椎间隙高度与上位椎体高度比值呈负相关（r =-0.568,P < 0.05）。结论 临床上测量L₂/L₃、L₃/L₄、L₄/L₅、L₅/S₁节段椎间隙高度与上位椎体高度比值对腰椎椎间盘退行性疾病的诊断可能具有重要意义。     

单侧双通道内窥镜下椎间盘切除术治疗腰椎术后退行性变1例报告

腰椎术后邻近节段退行性变(ASD)是腰椎后路融合术后的常见远期并发症^[1-2],其发生率为4%~31%^[3-5]。ASD由多种因素引起,继而产生新的神经压迫症状。Kambin等^[6]于1986年提出单侧双通道内窥镜下椎间盘切除术(UBED)治疗腰椎椎间盘突出症(LDH)^[7],其兼具了开放手术与微创手术的优点^[8]。本院采用UBED治疗腰椎术后ASD患者1例,现将诊疗过程报告如下。     

平山病的诊疗进展

平山病于1959年由日本学者Hirayama等^[1]首次报道，以不对称的上肢远端肌力减弱和肌肉萎缩为首发症状，常累及手腕和手指并以骨间肌、小鱼际肌及前臂尺侧肌肉萎缩为著，主要见于亚裔青年男性^[2]。Singh等^[3]的研究发现，平山病患者以第一骨间背侧肌和小指展肌受累最为常见。发病年龄一般为20~30岁，男性多于女性，但也有儿童及中年发病的报道^[4]。平山病症状常为单侧，约10%的患者出现双侧对称受累，且临床症状较重^[5]。超过95%的患者可自觉寒冷环境中力弱加重^[6]。临床体征为C₇~T₁脊髓节段支配的前臂、手部肌肉进行性萎缩，手、前臂肌力减弱，但肱桡肌不受累，可勾勒出典型的掌侧及背侧前臂肌肉萎缩的斜行边界，较少伴有感觉异常或锥体束征^[2，7]，受累肌肉收缩时可出现收缩震颤。患者肌肉牵张反射正常，锥体束征阴性，不伴有排尿异常及颅神经麻痹。Holla等^[8]报道了1例罕见的肩胛带肌受累病例，患者肌无力从双上肢远端逐渐发展至近端，出现无法穿衣、梳头等症状，查体可见翼状肩胛和菱形肌、冈上肌、冈下肌、胸大肌及前锯肌肌肉萎缩。平山病起病隐匿，与运动神经元病相似，但预后不同，提高对此病的诊断和治疗水平尤为重要。MRI检查及神经电生理检测技术有助于平山病的诊断和评估。目前平山病的治疗根据病情决定：病程短、症状轻的一般选择非手术治疗（颈托）；反之，则选择手术治疗。本文通过查阅近年平山病相关文献，分析其诊断及治疗方法，以期为平山病的诊治提供参考，现综述如下。     

腰椎退行性疾病手术病人术前邻近节段椎间盘的退变情况及分布规律

目的 观察腰椎退行性疾病手术病人术前邻近节段椎间盘的退变情况及分布规律。方法 回顾性分析济南军区总医院2012年1月至2016年2月收治的503例行手术治疗腰椎退行性疾病病人的术前临床资料,其中男240例（47.71%）,女263例（52.29%）;年龄为20~84岁,平均48.8岁。腰椎间盘突出症352例,退变性腰椎滑脱症91例,退变性腰椎管狭窄症60例。通过术前X线片评估腰椎稳定性;基于术前MRI,采用Pfirrmann分级标准评价腰椎间盘退变程度,记录Modic改变、高信号区域及许莫氏结节的发生情况。结果 503例中仅5例为单节段退变,12例为跳跃节段退变,余486例均为多节段退变。共1 863个（1 863/2 515,74.08%）腰椎间盘发生退变,5个节段椎间盘（L_1~2、L_2~3、L_3~4、L_4~5、L₅~S₁）均退变的病人比例为39.56%（199例）。不稳定节段数为127个,Modic改变为188个,高信号区域为241个,许莫氏结节节段数为161个。30岁以下男性病人腰椎间盘退变率较女性高;随着年龄增长,女性病人椎间盘退变率增加,退变程度加重。腰椎不稳、Modic改变、高信号区和许莫氏结节均与椎间盘退变存在明显相关性（P均＜0.05）。某一腰椎节段（L_3~4、L_4~5、L₅~S₁）椎间盘发生Pfirrmann Ⅳ、Ⅴ级退变时,邻近节段椎间盘退变（Pfirrmann Ⅲ+Ⅳ+Ⅴ级）比例均超过了80%,且严重退变（Pfirrmann Ⅳ+Ⅴ级）比例也较高,超过60%。结论 术前邻近节段椎间盘退变广泛存在,在临床工作中要予以重视。     

L4退行性滑脱的骨性参数特征

目的 比较L₄退行性滑脱和L₄/L₅椎间盘突出症患者骨性参数的差异,分析L₄退行性滑脱发生的危险因素。方法 回顾性分析21例L₄退行性滑脱（A组）及18例L₄/L₅椎间盘突出症患者（B组）的病例资料。通过测量腰椎矢状位X线片、45°双斜位X线片及CT获得骨性参数,矢状位X线片参数包括Taillard指数、腰椎指数（LI）、矢状面旋转度（SR）、骶骨水平角（SS）、腰椎前凸角（LL）、腰椎双凹指数（DCI）、L₄/L₅椎间盘角（IDA）、L₄/L₅椎间盘指数（DI）、腰椎重力线指数（LGLI）;45°双斜位X线片参数包括L₄椎体高度（h）、L₄小关节倾斜角（α）、L₃下关节突至L₄峡部距离（d）、L₅上关节突至L₄峡部距离（e）、L₄峡部宽度（k）;CT参数为L₄小关节角（θ）;比较2组各参数的差异,并分析各参数间的相关性。基于MRI图像,应用Pfirrmann椎间盘退行性变分级系统对2组患者L₄/L₅椎间盘进行分级,比较2组椎间盘退行性变分级的差异。结果 A组患者LI、IDA、DI、d、e、θ均明显小于B组,而LGLI、α以及L₄/L₅椎间盘退行性变程度均明显大于B组,差异均有统计学意义（P<0.05）。相关性分析显示Taillard指数与LI、θ呈负相关,与LGLI呈正相关。结论 椎间盘退行性变、α增大、LGLI增大、θ减小、LI减小、IDA减小、DI减小、关节突至峡部距离减小可能是L₄退行性滑脱发生的危险因素。     

L4～S1椎弓根形态与椎板间及椎间孔大小的相关性

目的 研究腰椎椎弓根形态（长度及角度）与L₄/L₅和L₅/S₁节段椎板间及椎间孔大小的相关性。方法 回顾性分析海军军医大学长征医院2020年1月—2022年6月收治的50例L₄/L₅或L₅/S₁单节段腰椎椎间盘突出症（LDH）患者作为研究组，并选取同时期50名健康志愿者作为对照组。测量2组腰椎正侧位X线片上L₄/L₅和L₅/S₁节段椎板间的最大高度和宽度，在CT上测量椎弓根长度和角度、椎间孔最小高度和宽度，采用逐步多元线性回归的多元相关性来确定相关变量对椎间孔及椎板间大小的独立影响。结果 2组L₄~S₁椎弓根长度、L₄/L₅及L₅/S₁节段椎间孔和椎板间高度差异无统计学意义（P>0.05）。研究组S₁椎弓根外展角小于对照组；研究组L₄椎弓根头倾角低于对照组，S₁椎弓根头倾角高于对照组；研究组L₄与L₅、L₅与S₁椎弓根头倾角差值低于对照组；研究组L₄/L₅和L₅/S₁节段椎间孔宽度、椎板间宽度小于对照组；以上指标差异均有统计学意义（P<0.05）。Pearson相关分析显示，年龄与椎板间高度和宽度及椎间孔高度呈负相关，椎弓根外展角与椎板间宽度呈正相关，椎弓根长度与椎间孔宽度呈正相关，相邻腰椎椎弓根头倾角差值与椎间孔宽度呈正相关，椎板间宽度与椎间孔宽度呈正相关。多重线性回归分析显示，患者的年龄、椎弓根长度及角度与椎板间及椎间孔大小独立相关，L₅、S₁椎弓根外展角与椎板间宽度显著正相关，L₅椎弓根头倾角与L₄/L₅及L₅/S₁椎间孔高度显著负相关；相邻腰椎椎弓根头倾角差值与椎间孔宽度显著正相关。结论 椎板间及椎间孔高度和宽度会随着患者年龄增长而变小，椎板间宽度随着L₅、S₁椎弓根外展角度增大而变大，L₅椎弓根头倾角越大，相邻椎间孔高度越小；相邻椎体椎弓根头倾角差值增加，椎间孔宽度增大。椎弓根角度和长度影响椎板间及椎间孔的大小，这些变化可能会影响手术难度和手术方式选择。     

Dynesys动态稳定系统治疗多节段腰椎退变性疾病的中远期临床疗效观察

目的:探讨Dynesys动态中和内固定系统治疗多节段腰椎退变性疾病的中远期临床疗效。方法:对2008年12月至2011年5月采用Dynesys系统治疗的多节段腰椎间盘突出症和多节段腰椎管狭窄症28例患者进行回顾性分析。其中男16例,女12例;年龄27～75岁,平均49.1岁。多节段腰椎间盘突出症13例,L₃-L₅ 7例,L₂-L₄ 1例,L₄-S₁ 5例;多节段腰椎管狭窄症15例,L₃-L₅ 10例,L₂-L₅ 4例,L₂-S₁ 1例。所有患者腰腿痛和(或)间歇性跛行症状经正规保守治疗6个月以上无效。记录手术前后患者的腰腿部疼痛视觉模拟评分(Visual analogue scale,VAS),通过影像学资料观察固定节段及头侧邻近节段的椎间隙高度和椎间活动度,采用Oswestry功能障碍指数(Oswestry Disability Index,ODI)对疗效进行评定。结果:28例患者均顺利完成手术,且均获得随访,随访时间38～65个月,平均50.6个月。末次随访时腰腿痛VAS评分分别为1.25±0.70和1.29±0.89,ODI为(25.10±6.52)%,腰腿痛VAS评分及ODI较术前有明显下降(p<0.05).术后随访固定节段椎间隙高度较术前有所升高,椎间活动度下降,与术前比较差异有统计学意义(p<0.05).术前及术后各随访时间点头侧邻近节段活动度、椎间隙高度差异无统计学意义(p>0.05).结论:Dynesys治疗多节段腰椎退变性疾病中远期临床疗效满意,能保留部分椎间活动度,对邻近节段影响小。Dynesys远期临床疗效还有待更长时间的随访观察。     

Coflex系统治疗退行性腰椎管狭窄症

 目的 探讨Coflex系统治疗退行性腰椎管狭窄症的初步临床疗效。
方法 2008年3月至2009年8,采用腰椎后路椎管减压棘突间植入Coflex系统治疗退行性腰椎管狭窄症患者26例,男11例,女15例;年龄45～78岁,平均65.4岁。L_3,4节段7例,L_4,5节段13例,L_3,4合并L_4,5节段6例。术前MRI和CT扫描证实L_3,4和（或）L_4,5节段黄韧带增厚,关节突关节骨质增生,合并椎间盘突出致中央椎管及侧隐窝狭窄,神经根或马尾受压。应用eFilm及CAD软件测量术前及术后3个月、12个月手术节段椎间隙前缘高度、后缘高度、活动度,术前、术后椎管面积;采用日本骨科学会评分标准（Japanese Orthopaedic Association,JOA）进行功能评估。
结果 全部病例随访12～24个月,平均15个月。术后患者腰腿疼痛症状均明显缓解,日常生活能力改善。JOA评分由术前平均（15.46±4.30）分改善至术后3个月（24.50±1.58）分,责任节段椎管面积由术前平均（218.4±16.2）mm 2增加至术后（264.6±9.9）mm 2。单节段椎间隙前缘高度无明显变化,椎间隙后缘高度较术前增加,随时间延长高度有所下降。术后手术节段仍保留一定的活动度,但较术前明显下降。Coflex系统无松动、断裂及脱出。
结论 Coflex系统治疗退行性腰椎管狭窄症可较好地维持相应节段的稳定性,安全可行,近期疗效满意。     

经皮内窥镜技术治疗老年单节段退行性腰椎椎管狭窄症

腰椎椎管狭窄症（LSS）是骨科常见病之一。随着我国老龄化的加速,老年退行性腰椎椎管狭窄症（DLSS）的发生率逐年增加,腰腿痛和间歇性跛行严重影响患者的生活质量^[1]。DLSS往往由椎间盘突出或合并钙化、小关节骨赘增生及黄韧带肥厚等原因引起,部分患者合并发育性椎管狭窄^[2-3]。临床上根据解剖部位将LSS分为中央管狭窄（椎管中央型狭窄）、关节下管狭窄（神经根管的关节下段,包括侧隐窝）和椎间管狭窄（椎弓根及椎间孔段）^[4-5]。老年DLSS患者一般病史较长,影像学资料提示多节段的椎间盘膨出或突出、黄韧带肥厚、小关节增生、侧隐窝狭窄,有时神经根病变的定位诊断也不明确,是否需要将所有狭窄的间隙部位减压,是否需要广泛的融合固定一直是临床争论的问题^[6]。传统腰椎减压融合术治疗DLSS效果明显,但手术创伤较大,术后感染、切口愈合不良、植骨区不融合、内固定松动断裂、邻椎病等手术并发症使得此类技术的应用受到限制^[7]。近年来,经皮内窥镜技术在治疗DLSS方面优势明显,通过术前病史询问、体格检查及相关影像学资料的反复研究,并根据病情需要可结合椎间盘造影,最终精准定位责任椎间隙及椎管狭窄部位行靶向穿刺,达到定点精准减压。2014年5月-2017年8月,本院采用经皮内窥镜下减压术并射频消融术治疗老年单节段DLSS患者40例,现将诊疗过程报告如下。     

颈椎人工椎间盘置换术患者选择与异位骨化形成的相关性分析

 目的 分析颈椎人工椎间盘置换术患者选择与术后异位骨化形成的相关性。方法 回顾性分析2003年12月至2008年12月,48例接受Bryan人工颈椎间盘置换术且随访时间超过5年的患者资料,男21例,女27例;年龄20~53岁,平均42岁;脊髓型颈椎病34例,神经根型颈椎病14例;单节段置换术38例,包括C_3-4 3例、C_4-5 5例、C_5-6 28例、C_6-7 2例;双节段置换术9例,包括C_4-5、C_5-6 4例、C_5-6、C_6-7 5例;三节段置换术1例（C_3-4、C_4-5、C_5-6）;共59个手术节段。在术后颈椎侧位X线片上使用McAfee分级法评价异位骨化形成。使用Logistic回归分析患者性别、术前手术节段活动度、置换节段脊柱功能单位曲度、置换节段与相邻节段椎间隙高度比值等因素与术后异位骨化形成的关系。对阳性结果及其选择阈值采用接受者操作特征（receiver operating characteristic, ROC）曲线及曲线下面积（area under the ROC curve, AUC）进行检验和量化分析。结果 48例患者术后均获得5年以上随访,随访时间60~120个月,平均70.3个月。术后59个节段中,20个出现异位骨化,发生率为33.9%（20/59）。患者性别、节段活动度、置换节段脊柱功能单位曲度和术前置换节段椎间隙高度这四方面因素中,仅术前置换节段与相邻节段椎间隙高度比值与术后异位骨化的形成具有显著相关性。通过ROC曲线分析该因素的AUC为0.813,95%置信区间为0.666~0.959,据此计算出病变节段与相邻节段椎间隙高度比值的临床最佳判断阈值为0.9。结论 患者选择相关临床因素中的术前置换节段椎间隙高度与术后异位骨化形成具有相关性;针对可变旋转中心的Bryan颈椎人工椎间盘假体,术前病变节段椎间隙高度较相邻节段丢失超过10%者不适合行人工椎间盘置换术。     

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.     

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.     

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.