椎弓根置钉导向器在重度脊柱畸形患者矫形手术中的应用

目的:探究3D打印的个性化椎弓根置钉导向器对于重度脊柱畸形患者(主弯Cobb角≥90°)矫形手术中辅助置钉的安全性和有效性。方法:回顾我院2017年1月～2017年9月采用椎弓根置钉导向器辅助置钉的13例(9女4男)重度脊柱畸形患者,平均手术年龄12.9±3.1岁(10～19岁),随访时间13.8±1.9个月(12～18个月)。术后2周CT测量椎弓根螺钉突破椎弓根皮质的程度,并将其分成0级(未突破椎弓根皮质)、1级(突破2mm)、2级(突破2～4mm)、3级(突破4mm),其中0级和1级认定为螺钉置入准确。测量并比较术前、术后2周、末次随访的主弯Cobb角、后凸角、冠状面平衡、脊柱矢状位轴,记录置钉相关并发症。结果:13例重度脊柱畸形患者术中在119枚椎弓根置钉导向器(238个椎弓根导向孔)的辅助下,成功置入232枚椎弓根螺钉,辅助置钉成功率97.5%(232/238)。依据CT测量分级,0级、1级、2级和3级螺钉数依次为111枚、84枚、33枚和4枚,置钉准确率为84.1%(195/232)。术后2周,主弯Cobb角由术前的110.6°±15.2°纠正至52.3°±16.2°(P0.05);后凸角由术前的58.3°±20.6°纠正至35.7°±10.4°(P0.05);冠状面平衡由术前的2.8±1.7cm纠正至1.7±0.5cm(P0.05);脊柱矢状位轴由术前的3.1±1.8cm纠正至1.4±0.4cm(P0.05)。末次随访与术后2周比较,无统计学差异(P0.05)。至末次随访时,未发生严重的置钉相关并发症。结论:椎弓根置钉导向器可为重度脊柱畸形患者提供准确性较高的辅助导航。     

连续置钉或间隔置钉矫治LenkeⅠ型青少年特发性脊柱侧凸的效果

目的:对比后路间隔置钉或连续置钉矫治LenkeⅠ型青少年特发性脊柱侧凸的效果。方法:将2004年1月～2006年6月期间收治的32例LenkeⅠ型青少年特发性脊柱侧凸患者随机分成两组,一组手术方法为后路矫形侧连续置入椎弓根螺钉进行矫形(连续置钉组);另一组手术方法为后路矫形侧均间隔一个椎体置入椎弓根螺钉进行矫形(间隔置钉组)。记录所有患者冠状面和矢状面的术前侧凸Cobb角、术后侧凸Cobb角、术后侧凸矫正率并进行两组间比较分析。结果:两组患者术中均无神经脊髓损伤。胸椎侧凸冠状面、矢状面Cobb角连续置钉组术前分别为62.7°±12.7°、28.3°±11.6°;术后分别为14.5°±6.9°、20.5°±10.7°;间隔置钉组术前分别为63.9°±10.9°、28.1°±10.8°,术后分别为14.7°±6.4°、21.0°±10.3°;连续置钉组和间隔置钉组术前C7铅垂线与S1椎体后缘的距离分别为-3.3±6.1cm、-4.4±4.8cm,术后分别为1.4±3.3cm、0.9±3.0cm。两组患者术前及术后冠状面、矢状面侧凸Cobb角及C7铅垂线与S1椎体后缘距离无统计学差异(P0.05)。结论:间隔置钉和连续置钉矫正LenkeⅠ型青少年特发性脊柱侧凸效果相比较无统计学差异。     

引导通道辅助下经皮椎弓根置钉与传统经皮椎弓根置钉的比较

目的 :比较引导通道辅助下经皮椎弓根置钉与传统透视下经皮椎弓根置钉的手术时间、射线暴露时间和置钉准确性。方法:70例无神经症状的胸腰椎骨折患者,随机分为A、B两组,A组35患者采用传统透视下经皮置入椎弓根螺钉,共置入180枚椎弓根螺钉;B组35例患者采用引导通道辅助下经皮置入椎弓根螺钉,共置入178枚椎弓根螺钉,均由同一术者完成置钉。记录两组椎弓根置钉时间、射线暴露时间,术后连续2次复查手术节段CT对两组病例置钉准确性进行评估并分级。比较两组患者单枚椎弓根螺钉置钉时间、射线暴露时间和置钉准确性。结果:两组患者年龄、体重指数、合并疾病、骨折类型、性别比例均无统计学差异(P0.05)。A组单枚椎弓根螺钉平均置钉时间为14.11±3.32min,B组为11.35±2.82min,两组比较差异有统计学意义(P=0.0042)。A组平均射线暴露时间为12.07±3.06s,B组为8.06±2.15s,两组比较差异有统计学意义(P=0.0031)。A组155枚(86.11%)螺钉为A级置钉,23枚螺钉(12.78%)为B级置钉,1枚螺钉(0.56%)为C级置钉,1枚螺钉(0.56%)为D级置钉;B组156枚螺钉(87.64%)为A级置钉,20枚螺钉(11.24%)为B级置钉,1枚螺钉(0.56%)为C级置钉,1枚螺钉(0.56%)为D级置钉,两组比较差异无统计学意义(P0.05)。结论 :引导通道辅助下经皮椎弓根置钉与传统经皮椎弓根置钉具有相同的准确性,但能明显减少置钉时间及辐射暴露时间。     

置钉密度与Lenke1型青少年特发性脊柱侧凸矫正率的相关性

[目的]回顾性分析全椎弓根螺钉矫形治疗Lenke 1型青少年特发性脊柱侧凸矫正率与置钉密度间的相关性.[方法]2007～2009年,56例行后路全椎弓根螺钉矫形内固定的Lenke 1型青少年特发性脊柱侧凸患者纳入回顾性研究.测量术前、术后影像学资料,分析侧凸矫正率与置钉密度的相关性.[结果]所有患者无手术相关的严重并发症发生.主胸弯角度由术前平均53.4°±11.7°矫正为18.4°±10.5°(P<0.05),冠状面平均矫正率为66.8%.胸椎后凸由术前31.8°±4.39°降至22.3°±3.13°(P<0.05).平均置钉密度为1.56 (1.0～2.0).矢状面胸椎后凸的减小与冠状面Cobb角的矫正度数和矫正率明显相关(P<0.05).置钉密度与侧凸矫正率无相关性.[结论]椎弓根螺钉系统治疗胸椎特发性侧凸可以获得良好的冠状面矫形,但会造成矢状面胸椎后凸减小.置钉密度与侧凸的矫正率无相关性.     

枢椎椎弓根螺钉置钉失误的影像学分析

目的:分析枢椎椎弓根螺钉置钉失误的原因,探讨提高置钉成功率的方法。方法:2002年1月～2006年12月我院因上颈椎外伤、脱位和肿瘤接受寰枢椎后路内固定手术的患者50例,共置入100枚枢椎椎弓根螺钉。根据术前CT薄层扫描结果将枢椎椎动脉孔分为Ⅰ、Ⅱ、Ⅲ、Ⅳ型;在术后颈椎侧位X线片上测量枢椎椎弓根螺钉钉道上倾角,在术后CT片上测量钉道内倾角,并根据CT结果将置钉失误分为两类,A类为钉道偏内指向椎管,B类为钉道偏外指向椎动脉孔。结果:100个枢椎椎动脉孔分为Ⅰ型76个,Ⅲ型10个,Ⅳ型14个。100枚枢椎椎弓根螺钉共发生A类失误8枚(8%),其中Ⅰ型5枚,Ⅲ型1枚,Ⅳ型2枚;B类失误2枚(2%),其中Ⅲ型、Ⅳ型各1枚。Ⅰ型、Ⅲ型、Ⅳ型的置钉失误率分别为6.6%、20%、21.4%。A类失误组的钉道上倾角为14.8°±8.5°,明显小于钉道正确组的18.3°±9.7°(P<0.05),B类失误组为17.5°±6.8°,与正确钉道组无显著性差异(P>0.05)。A类失误组的钉道内倾角为21.4°±7.1°,明显小于钉道正确组的33.7°±7.3°(P<0.05);B类失误组为44.9°±8.8°,明显大于正确钉道组(P<0.05)。结论:枢椎椎动脉孔的解剖变异是导致置钉失误的客观因素;而术中钉道内倾角和上倾角偏小是引起置钉失误的最常见原因。术前应根据CT扫描结果充分掌握枢椎椎动脉孔的特点,结合"宁上勿下,宁内勿外"的原则,合理把握钉道方向,以提高置钉成功率。     

后路截骨联合椎弓根内固定矫形治疗僵硬性脊柱侧后凸畸形

目的探讨经后路截骨联合椎弓根内固定矫形治疗僵硬性脊柱侧后凸畸形疗效。方法对26例僵硬性脊柱侧后凸畸形患者进行后路截骨、椎弓根内固定矫形。8例行后路Ponte截骨,13例行椎弓根截骨术(PSO)联合Ponte截骨,5例行全椎体切除术(VCR)。比较患者术前、术后和末次随访时Cobb角的变化及C7中垂线与骶骨中垂线距离的变化。结果患者均获得随访,时间12~60个月。侧凸Cobb角:术前30°~135°(90.7°±30.6°),术后12°~30°(18°±5.6°),矫正率为82.5%,末次随访13°~32°(20°±5.8°),丢失4.3%;后凸Cobb角:术前20°~60°(40.6°±18.5°),术后10°~26°(16.8°±6.2°),矫正率为85%,末次随访13°~30°(20.5°±7.0°),丢失3.7%;C7中垂线与骶骨中垂线距离:术前3.8~6.5(5.1±1.3)cm,术后0.3~1.3(0.7±0.3)cm,末次随访0.4~1.7(0.8±0.3)cm。所有患者未发生神经损伤等并发症,仅1例患者术后3个月出现内固定松动,经延长固定节段后骨性融合。结论术前充分的评估,选择合适的后路截骨方式,联合椎弓根内固定矫形治疗僵硬性脊柱侧弯,能有效矫正畸形和恢复脊柱冠、矢状面平衡。     

O型臂3D导航与徒手置钉在上颈椎椎弓根螺钉置入中的精确性比较

目的 :比较O型臂3D导航下C1、C2椎弓根螺钉置钉与徒手置钉精确性的差异,探讨O型臂导航在上颈椎椎弓根螺钉置钉中的应用价值。方法:纳入我院C1、C2椎弓根螺钉内固定患者62例,分为导航置钉组(A组)与徒手置钉组(B组)。A组:2014年1月~2015年3月,O型臂导航下行C1、C2后路椎弓根螺钉内固定术22例,男15例,女7例,年龄17~58岁(40.8±12.7岁);B组:2005年3月~2013年12月经徒手置入C1及C2椎弓根螺钉患者40例,男26例,女14例,年龄12~70岁(42.0±15.6岁)。所有患者术后均行颈椎CT平扫,按照Neo等的方法,根据椎弓根螺钉穿破椎弓根皮质的程度将置钉精确性分为四级(0级,螺钉完全处于椎弓根中,没有穿破骨皮质;1级,螺钉穿破皮质2mm,或小于螺钉直径的50%;2级,螺钉穿破皮质≥2mm且﹤4mm,或大于螺钉直径的50%但没完全穿出;3级,完全穿出皮质,螺钉处于椎管或椎动脉孔内),分别评估两组的置钉精确性并比较两组间的差异。结果:A组共置入C1、C2椎弓根螺钉67枚(C1 28枚,C2 39枚),其中0级60枚(89.6%),1级7枚(10.4%),无2级或3级不良置钉;B组共置入C1、C2椎弓根螺钉134枚(C1 64枚,C2 70枚),其中0级116枚(86.6%),1级13枚(9.7%),2级4枚(3.0%),3级1枚(0.7%)。两组间置钉精确性分级(P=0.49)及0级置钉率(P=0.55)均无统计学差异;A组未发现不良置钉,B组不良置钉发生率为3.7%,但组间无统计学差异(P=0.17)。两组均无置钉相关的血管、神经并发症发生。结论:术中O型臂导航与徒手置钉在上颈椎椎弓根螺钉置钉精确性上并无统计学差异,虽然导航能提供清晰的术中3D图像,但该技术未能完全避免置钉时螺钉轻度穿破骨皮质的发生,仍需提高术者与导航系统间的交互作用,完善操作技术,进一步提高置钉精确性。     

标杆型3D打印导板辅助寰枢椎椎弓根置钉准确度分析

目的探讨标杆型3D打印导板辅助寰枢椎椎弓根置钉的可行性,并进行置钉准确度分析。方法 2014年6月—2015年8月,本院收治寰枢椎脱位患者21例,男12例,女9例;年龄12~54岁,平均42.6岁。术前使用Mimics 17.0软件和3-matic 9.0软件为每例患者制作标杆型3D打印导板,术中使用标杆型3D打印导板辅助寰枢椎椎弓根置钉,术后患者行颈椎CT平扫。在Mimics 17.0软件中,将手术前后的寰枢椎模型及螺钉配对拟合,调整空间坐标轴,测量并比较术前预设钉道与术后实际钉道的内倾角、头倾角、进钉点坐标。结果 21例患者手术顺利,手术时间(193±51)min,术中出血量(384±127)m L。共置入寰椎椎弓根螺钉30枚,枢椎椎弓根螺钉42枚。除2枚寰椎椎弓根螺钉侵入椎管≤2 mm外,其他螺钉均位于椎弓根骨皮质内。寰椎左右侧预设最佳钉道内倾角度分别为9.4°±1.8°、9.8°±1.6°,实际钉道内倾角度分别为8.7°±1.6°、10.6°±2.2°;左右侧预设最佳钉道头倾角度分别为8.9°±2.5°、8.8°±2.3°,实际钉道头倾角度分别为9.3°±2.9°、9.4°±3.5°。枢椎左右侧预设最佳钉道内倾角度分别为21.9°±6.6°、22.4°±6.9°,左右侧实际钉道内倾角度分别为24.1°±6.3°、20.8°±6.4°;左右侧预设最佳钉道头倾角度分别为23.7°±7.3°、24.2°±7.2°,左右侧实际钉道头倾角度分别为22.1°±7.9°、22.3°±7.6°。寰枢椎术后实际钉道与术前预设最佳钉道的内倾角、头倾角、进钉点坐标差异均无统计学意义(P0.05)。结论标杆型3D打印导板辅助寰枢椎椎弓根置钉方向可调整性好,置钉准确度较高,为临床寰枢椎置钉提供了一种新的方法。     

MPR-CT个体化重建技术在脊柱侧凸术中的应用

目的评价在脊柱侧凸术中应用多平面重建(MPR)-CT技术的价值。方法比较应用MPR-CT个体化重建技术在脊柱侧凸患者中椎弓根螺钉植入的准确性。38例患者分为2组:MPR-CT组20例,对照组18例。两组术前平均Cobbs角分别为58.6°±20.4°和54.3°±19.8°。MPR-CT组术前进行单椎体椎弓根平面扫描重建,评价椎弓根的旋转角度、适宜进钉点、进钉长度、矢状位倾斜角度。术中均采用徒手椎弓根穿刺技术记录术中一次性椎弓根穿刺成功率。术后根据CT检查评估椎弓根螺钉植入位置,穿孔螺钉测量与理想进钉角度差。X线评价术后Cobb角和矫正率。结果术后Cobb角:MPR-CT组为18.7°±13.6°,对照组为19.3°±14.2°,矫正率分别为68.1%和64.4%。椎弓根一次穿刺成功率:MPR-CT组为91.2%,对照组为85.4%。穿孔率:MPR-CT组为4.5%,对照组为9.3%。穿孔螺钉测量较理想进钉角度差:MPR-CT组为7.2°±5.1°,对照组为9.2°±4.9°。两组年龄、术前、术后Cobb角、矫正率差异无统计学意义(P0.05)。在一次性穿刺成功率、螺钉穿破率及穿孔螺钉测量较理想进针角度差异有统计学意义(P0.05)。38例均未出现血管和脊髓损伤等并发症。结论脊柱侧凸患者的椎体旋转是重要的术前评估指标,术前MPR-CT检查可详细了解椎体旋转,减少椎弓根螺钉穿孔。     

伤椎置钉植骨后路短节段固定治疗胸腰段骨折

[目的]观察经伤椎椎弓根置钉、植骨后路短节段固定治疗胸腰段压缩性骨折的临床疗效。[方法]2013年1月~2015年1月本院21例胸腰段压缩性骨折采用经伤椎椎弓根置钉、植骨后路短节段固定,术前CT检查测量椎管占位比,术前、术后、去除内固定前或末次随访时X线片测量骨折椎体前缘压缩率、Cobb角并评估神经功能情况。[结果]患者均顺利完成手术,受伤至手术时间平均4.7 d(1~13 d),伤口均Ⅰ期愈合,术后X线片示脊柱序列和生理曲度基本恢复。术前前柱平均压缩39.3%(19%~64%),术后即刻8.3%(1%~17%),手术矫正31%;末次随访前柱压缩14.6%(4%~20%),平均丢失6.3%。Cobb角术前平均18.7°(10°~29°),术后平均1.7°(-9°~6°),平均矫正17°,术后畸形得到明显改善;末次随访时Cobb角平均4.6°(-8°~10°),丢失2.9°。平均随访18个月(10~34个月),椎体骨折愈合,无内固定失败,脊髓神经不完全损伤神经功能均有不同程度恢复。[结论]经伤椎椎弓根置钉、植骨,后路短节段固定可恢复并有效维持矢状位序列,减少椎体矫正度的丢失及内固定并发症的发生,是治疗胸腰段压缩性骨折一种安全、有效的方法。     

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.