枕颈融合术后吞咽困难评估及预测方法的研究进展

枕颈融合术(occipitocervical fusion, OCF)用于治疗因各种原因(创伤、类风湿关节炎、感染、肿瘤、先天畸形和退化等)导致的颅颈交界不稳定。通过OCF可获得满意的融合率并重建枕颈稳定性。吞咽困难为OCF术后常见的并发症, 严重影响患者术后的生活质量。对吞咽困难的评估主要采用Bazaz吞咽困难评分、吞咽生存质量量表(swallowing quality of life, SWAL-QOL)及进食评估问卷调查表-10(eating assessment tool-10, EAT-10)评分, 而临床主要通过颈椎曲度相关参数(O-C2角、O-EA角、Oc-Ax角、PI角)的变化预测吞咽困难的发生。目前, 临床评估及预测吞咽困难的方法很多, 但最佳评估方法尚不确定。本文对OCF术后吞咽困难的评估及预测方法进行综述, 显示Bazaz吞咽困难评分、SWAL-QOL评分及EAT-10评分量表评估OCF术后吞咽困难具有良好的适用性, 而在OCF术中通过调整使O-C2角>-5°、O-EA角>100°、Oc-Ax角>65°、术后PI角较术前PI角增加(即dPI角)≥...     

地舒单抗在骨巨细胞瘤新辅助治疗中的应用研究进展

骨巨细胞瘤（GCTB）是一种具有局部侵袭倾向的原发性良性骨肿瘤,以局部溶骨性病灶为特征。GCTB可发生局部复发和远处转移^［1-2］,占所有原发性骨肿瘤的3% ~ 5%,好发年龄为20 ~ 40岁^［1,3］。好发部位为长骨干骺端,约半数发生于股骨下端与胫骨上端,少数严重者软骨下可受累,出现关节功能障碍［4］;发生在脊柱的病灶以骶骨最为多见,其次为腰椎、胸椎、颈椎^［5］。近年来,GCTB的治疗模式逐渐从外科治疗转变为以外科治疗为主、药物治疗辅助的综合治疗。随着新辅助治疗理念的兴起,地舒单抗被广泛应用于GCTB的治疗,其可延缓肿瘤进展、降低手术分期等^［1］。地舒单抗是一种全人源性单克隆抗体,可与核因子-κB受体活化因子配体（RANKL）特异性结合直接抑制破骨细胞功能。然而,也有部分研究^［6］表明,术前应用地舒单抗可能会增高术后局部复发的风险。地舒单抗术前应用时长存在争议,并有少数报道^［7］提出,地舒单抗可能与肿瘤恶变有关。本文通过查阅相关文献,并重点回顾近5年的相关研究,对地舒单抗作为GCTB新辅助治疗药物的应用作如下综述。     

选择性神经根阻滞的价值和争议

选择性神经根阻滞（SNRB）是指对患有脊柱退行性疾病的患者，经查体后在影像学技术（X线，CT和B超）的辅助引导下，对高度怀疑病变的神经根（颈、胸、腰、骶）进行选择性地穿刺、定位、阻滞、治疗的一种微创技术^［1-2］。随着微创精准医疗理念的不断发展，SNRB的临床应用越来越广泛，可定位诊断和治疗病变神经根。当SNRB作为诊断方法时，强调定位的精准性，操作要求神经根定位明确，药物阻滞精准，尽量减小阻滞范围，降低假阳性的发生率。随着微创手术技术的广泛开展，多节段脊柱退行性疾病中责任神经根的术前精准定位至关重要，SNRB在明确责任节段、减少手术节段、预测术后效果方面具有重要意义^［3-5］。当SNRB作为治疗方法时，强调治疗的有效性，操作要求在降低并发症的同时，尽量增加SNRB的效果和持续时间。作为一种简单有效的脊髓硬膜外注射方法，SNRB广泛应用于颈肩腰腿痛的治疗，并取得了良好效果^［6-7］。     

混合现实技术引导的经皮内窥镜下腰椎椎间盘切除术的初步探索与应用

经皮内窥镜下腰椎椎间盘切除术（PELD）已经成为治疗腰椎椎间盘突出症（LDH）的首选方法^［1-3］。腰椎椎间盘突出类型多样化,术前须精确定位突出椎间盘的“靶点”位置,确定进针点、深度和角度等相关参数,以便术中可按照术前设计快速准确地穿刺和置入工作通道,这是靶向穿刺技术的核心,也是尽可能减少不必要创伤并发症的基础^［4］。常规手术通道的建立,需要根据椎间盘突出的不同病理类型并结合临床实践确定,且术中需要C形臂X线机透视辅助,存在学习曲线陡峭、辐射量大、手术风险高等问题^［5-6］。混合现实（MR）技术是近年发展起来的一门新兴技术,其将虚拟现实（VR）技术与增强现实（AR）技术相结合,操作者可从MR技术呈现的全息影像中获取相关信息,从而实现虚拟和真实的交互^［7-8］。目前,MR技术在复杂的脑外科手术、髋关节手术中已有应用,并获得良好的临床疗效^［9-11］,但尚无其应用于PELD的报道。本研究组在MR技术引导下,对1例LDH患者行PELD,取得了良好的临床疗效,现报告如下。     

枕颈CD在上颈椎疾患手术治疗中的应用

枕颈区域的不稳,包括寰枕关节及寰枢关节不稳,如齿状突骨折、横韧带断裂以及上颈椎的畸形等,患者常表现为高位脊髓受压症状并呈进行性加重。当保守的方法,如颅骨牵引、头颅双向牵引不能得到满意的疗效时,需行手术治疗。常用的方法有后路枕骨大孔扩大减压及C1、C2椎板切除减压,前路经口寰椎前弓及齿状突切除减压。这样,上颈椎的稳定性就成为术后疗效的关键。为了解决枕颈不稳,我们自1998年利用枕颈CD对21例不同原因引起枕颈部不稳的患者行前路和/或后路减压术,对其中4例外伤性寰枢椎爆裂骨折的患者进行了枕颈内固定植骨融合术,取得了较好的临床效果。总结如下。     

新型冠状病毒感染者脊柱外科急诊手术的围手术期管理专家共识

自2019年12月以来,已有200余个国家和地区相继报道了新型冠状病毒感染病例,世界卫生组织（WHO）于2020年3月12日宣布新型冠状病毒全球大流行,截至6月18日,全球已累计有824万余人感染,44万余人死亡,对全世界医疗、政治和经济领域影响巨大^［1-2］。WHO将其命名为“2019冠状病毒感染性疾病”（COVID-19）,病原体被命名为重症急性呼吸综合征冠状病毒2（SARS-CoV-2）^［3-6］。按照《中华人民共和国传染病防治法》,COVID-19被纳入乙类传染病,采取甲类传染病的预防控制措施^［7］。     

基于枕颈影像参数的枕颈融合术后吞咽困难风险分析

目的 基于枕颈影像参数探讨枕颈融合术后吞咽困难的危险因素.方法 选择2018年8月～2020年8月本科收治的84例枕颈交界区不稳患者,均采用枕颈融合术治疗,调查其术后吞咽困难发生情况,设为吞咽困难组及吞咽正常组;比较两组治疗前后的枕颈影像参数,即治疗前后Oc-Ax角、O-C2角、O-EA角以及nPAS以及变化值,并采用多因素Logistic回归分析调查枕颈融合术后吞咽困难的危险因素.结果 术后25例发生吞咽困难;吞咽困难组与吞咽正常组的术前、术后1年O-C2角以及ΔO-C2角差异有统计学意义(P<0.05);两组术前Oc-Ax角、O-EA角以及nPAS差异无统计学意义(P>0.05),两组术后1年Oc-Ax角、O-EA角、nPAS以及各指标的变化值差异有统计学意义(P<0.05).多因素Logistic回归分析显示,ΔO-C2角≤-5°、术后Oc-Ax角≤65°、术后nPAS≤10 mm、术后O-EA角≤100°是枕颈融合术后吞咽困难的危险因素.结论 枕颈交界区不稳患者采用枕颈融合术治疗后吞咽困难发生率较高,O-C2角变化值较大和术后Oc-Ax角、nPAS、O-EA角过小均会增加吞咽困难的风险.     

新枕颈距离测量方法在颅底凹陷症手术中的应用及临床意义

目的:采用C4椎体中心至McGregor线垂直距离(the occiput-C4 distance,OC4D)测量颅底凹陷症(basilar invagination,BI)患者枕颈距离,并探讨其在枕颈融合术(occipitocervical fusion,OCF)中评估患者枕颈区纵向复位程度的可行性及临床意义。方法:回顾性分析2014年1月～2019年1月在我院就诊的82例颅底凹陷症患者的临床资料,男性23例,女性59例,平均年龄50.3±9.6岁,行OCF手术治疗56例,男性17例,女性39例,其中3例患者术后出现发音困难、吞咽困难、咽反射减弱等低位颅神经麻痹症状且无法耐受,考虑与术中患者枕颈区过度纵向撑开有关,行翻修手术以减少患者枕颈区纵向撑开距离。测量82例患者入院后术前自然站立位颈椎侧位中立位片、过伸及过屈位片上OC4D值;56例手术患者(53例OCF术后常规恢复患者和3例OCF术后翻修患者)术后住院期间复查的自然站立位颈椎侧位片上OC4D值及3例OCF术后翻修前自然站立位颈椎侧位片的OC4D值,2名脊柱外科医生不同时间单独进行2次测量。在56例手术患者入院和术后复查的颈椎CT检查中分别测量齿突尖到McRae线的垂直距离(the distance of the tip of odontoid to the McRae line,McRL)。计算53例OCF术后症状改善患者和3例OCF术后翻修患者枕颈区的纵向复位距离(患者术后OC4D值-患者术前OC4D值,d-OC4D);记录手术患者术前及术后12个月随访时日本骨科科协会(Japanese Orthopaedic Association,JOA)评分值(17分法),计算手术患者枕颈区纵向复位率和神经功能改善率。结果:82例患者入院颈椎中立位OC4D值为49.1±7.6mm,过屈位为49.0±7.5mm,过伸位为49.0±7.7mm,三者间差异无统计学意义(P0.05)。颈椎中立位、过伸位及过屈位OC4D测量值在观察者间的ICC分别为0.951、0.963和0.949(P0.05),观察者内的ICC分别为0.977、0.982和0.971(P0.05)。56例手术患者中,3例行翻修手术患者术后低位颅神经麻痹症状明显缓解。56例手术患者(3例患者为翻修术后)McRL值由术前6.3±2.8mm降至术后1.8±1.2mm,颈椎中立位OC4D值由术前48.9±6.0mm增至术后53.5±6.6mm,枕颈区纵向复位距离为4.8±1.2mm,95%参考值范围为2.4～7.2mm。JOA评分由术前11.84±2.70分提高至术后12个月随访时14.88±1.74分,差异有统计学意义(P0.05)。手术患者枕颈区平均纵向复位率为65.8%;神经功能平均改善率为70%。d-OC4D与复位率、神经功能改善率之间相关系数r分别为0.831、0.725(P0.001)。结论 :OC4D测量是一种简单有效的枕颈距离测量方法,在颅底凹陷症经后路枕颈融合术前可用于预估患者枕颈区纵向撑开复位的距离,术中可用于即时评估枕颈区纵向撑开复位情况,保证患者枕颈区获得充分减压复位的同时,可避免枕颈区过度纵向撑开而引起相关术后并发症。     

弯角经皮椎体成形术治疗骨质疏松性椎体压缩性骨折术后的骨水泥分布

经皮椎体成形术（PVP）治疗老年骨质疏松性椎体压缩性骨折（OVCF）已广泛应用于临床,并取得了令人满意的效果^［1］。但是,随着该项技术的开展,许多因骨水泥分布不均导致的并发症也随之产生,如再骨折、邻近椎体骨折甚至脊柱侧凸等^［2-3］。因此,如何改进技术,使骨水泥在椎体内平衡分布,是目前的研究热点之一。濮阳市油田总医院2016年1月—2018年1月采用弯角经皮椎体成形术（PCVP）和PVP治疗OVCF患者175例,本研究通过分析术中骨水泥用量及术后分布状态,为临床工作提供参考,现报告如下。     

关节镜治疗婴幼儿化脓性膝关节炎的疗效分析

目的 探讨关节镜治疗婴幼儿化脓性膝关节炎的疗效。方法 回顾性分析2016年2月至2020年3月我院小儿骨科收治的16例婴幼儿化脓性膝关节炎的临床资料,患儿入院即给予足量敏感抗生素治疗,择期采用直径2.7 mm关节镜系统行膝关节清创术,其中10例术后留置冲洗引流、6例未行引流。记录患儿体温、儿童疼痛行为量表（FLACC）评分、应用躁动评分（SAS）、MRI髌上囊积液最大宽度及白细胞计数（WBC）、中性粒细胞计数（NEUT）、红细胞沉降率（ESR）、C-反应蛋白（CRP）及降钙素原（PCT）等感染指标。结果 所有患儿均获得随访,随访时间为（38.44±11.44）个月（23~63）个月。术后体温［（36.86±0.22） ℃］、FLACC评分［（2.19±0.91）分］、SAS评分［（1.25±0.45）分］、MRI髌上囊积液最大宽度［（4.88±1.67） mm］、WBC［（7.45±2.01）10⁹/L］、NEUT［（3.86±1.18）10⁹/L］、ESR［（14.81±4.00） mm/h］、CRP［（14.75±5.90） mg/L］及PCT［（0.04±0.02） ng/mL］均低于术前（P＜0.05）。但引流组与未引流组体温、FLACC评分、SAS评分、MRI髌上囊积液最大宽度及WBC、NEUT、ESR、CRP及PCT的差异无统计学意义（P＞0.05）。末次随访时患儿两侧膝关节活动度比较,差异无统计学意义（P＞0.05）,未见膝关节内外翻畸形或下肢短缩等并发症。结论 采用直径2.7 mm的关节镜系统治疗婴幼儿化脓性膝关节炎,可以有效显露和清理脓性组织,增加感染治愈率,避免切开引流造成的继发损伤。     

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.     

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.     

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.     

Is the recovery profile of mivacurium independent of the rate of decay of its plasma concentration in patients with normal plasma cholinesterase activity?

Background: The duration of action of muscle relaxants is poorly correlated to the rate of decay of their plasma concentration. The plasma concentration of mivacurium may rapidly decrease below its active concentration because of the extensive hydrolysis of mivacurium. By inflating a tourniquet on one upper limb for 3 min after the administration of atracurium, mivacurium or vecuronium, we studied the influence of the initial decline of their plasma concentration on their effect. Methods: In 50 patients anaesthetised with thiopental, isoflurane and fentanyl, the effect of bolus doses of 0.15 or 0.25 mg . kg^?1 mivacurium (MIV 15, MIV 25), 0.3 or 0.5 mg . kg^?1 atracurium (ATR 30, ATR 50) and 0.06 or 0.1 mg . kg^?1 vecuronium (VEC 06, VEC 10) were measured on both arms (evoked response of the adductor pollicis to train-of-four stimulation every 12 s), a tourniquet being applied on one arm just before and during 3 min after the muscle relaxant bolus. Results: Tourniquet inflation of 3 min almost abolished the neuromuscular effect of mivacurium. In the vecuronium groups and in the ATR 50 group, tourniquet inflation did not modify the maximum degree of depression of the twitch response. Also, the duration of action of vecuronium was unaffected by the tourniquet. In the ATR 30 group, times to return of the twitch response to 25% (duration 25%) and 75% (duration 75%) of control response were significantly shorter in the cuffed arm, 23 min vs 27 min, and 41 min vs 45 min, respectively. In the ATR 50 group, only duration 25% was significantly shorter in the cuffed arm (41 min vs 45 min). Conclusion: The results suggest that the rate of decline of the plasma concentration of mivacurium is so rapid, that a very low and almost clinically ineffective concentration is present as soon as 3 min after its administration. The results also indicate that the recovery from a mivacurium-induced neuromuscular blockade is not influenced by the rate of decay of its plasma concentration in patients with genotypically normal plasma cholinesterase.     

Membranes in Artificial Organs

Abstract: Membrane processes play a pivotal and enabling role in modern replacement therapy for acute and chronic organ failure and in the management of immunologic diseases. In fact, virtually all contemporary extracorporeal blood purification methods employ membrane devices, and the next generation of artificial organs and tissue engineering therapies are almost certain to be similarly grounded in membrane technology. In this short essay, we comment on the similarities and differences among synthetic membranes and their natural counterparts and also provide a critical overview of the demographics and technology of hemodialysis, hemofiltration, apheresis, oxygenation, and emerging membrane technologies and applications.     

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.     

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.