增龄变化对血管移植材料脐带静脉顺应性的影响

背景：血管重建术中内径小于6mm的人工合成血管替代人体小动脉或静脉一直未获得满意的效果，因而目前小动脉及静脉代用品成为亟待解决的问题，目的：观察不同胎龄脐带静脉压力-容积关系，为血管移植材料脐带静脉的生物力学性质上提供实验数据：设计；非随机对照实验。材料：实验于2004—06在郧阳医学院医用生物力学实验室完成，湖北省十堰市太和医院妇产科收集胎龄在24～42周自然流产或分娩的正常胎儿脐带静脉50条（经产妇许可），产妇年龄20～30岁。其中胎龄24～27周8例，28～32周7例，33～36周8例，37周4例，38周5例，39周5例，40周5例，41周4例，42周4例。干预：取胎儿脐带50条．测量一段脐带长度（2cm）并标记两端点后，切下脐带置于生理盐水中。仔细地对脐带静脉进行机械剥离后，将试件两端标记点固定在软组织生物力学试验台上，测定其压力-容积关系，计算出顺应性：主要观察指标：不同脐带静脉的压力、容积及顺应性。结果：50条脐带全部进入结果分析，①37～40周脐带静脉压力-容积曲线比较接近，而28周，42周脐带静脉压力-容积曲线幅度明显下降，经二次回归分析可见38周胎龄压力-容积曲线回归系数绝对值最大。②脐带静脉顺应性随胎龄增加而增大[24～27周（2．22&;#177;0．34）&;#215;10^-4mL／（kPa、cm），28～32周（3．65&;#177;0．461&;#215;10^-4mL／（kPa、cm）,33～36周（4．22&;#177;0．55）&;#215;10^-4mL／（kPa&;#183;cm），37周（7．63&;#177;0．48）&;#215;10^-4mL／（kPa&;#183;cm），38周（8．32&;#177;0．76）&;#215;10^-4mL／（kPa、cm）]，但39周以后又降低[39周（7．61&;#177;0．46）&;#215;10^-4mL／（kPa&;#183;cm），40周（7．53&;#177;0．72）x10^-4ml／（kPa、cm），41周（4．13&;#177;0．35）&;#215;10^-4mL／（kPa、cm），42周（2．25&;#177;0．62）&;#215;10^-4mL／（kPa&;#183;cm）]。37～40周脐带静脉的顺应性较相近，而42周及28周以下脐带静脉的顺应性与37～40周比较（F=65．84—86．52，P〈0．01）。结论：人脐带静脉是动脉移植物的良好替代材料，在移植时除了考虑脐带静脉与宿主动脉相匹配外，还应注意其顺应性与胎龄的关系，实验结果提示，胎龄在37—40周的脐带静脉作为临床应用的移植材料较为理想．     

微重力环境下立位耐力不良的发生机制(英文)

目的:观察模拟失重对兔股静脉压力-容积关系的影响及静脉壁显微结构的变化,探讨微重力环境下造成立位耐力不良的发生机制。方法:采用头低位(-20°)倾斜的方法作为模拟失重家兔模型。24只雄性健康新西兰兔,随机分为对照组、模拟失重21d组和模拟失重10d组,每组8只。进行股静脉的压力-容积关系测试,并观察血管壁的显微结构。结果:模拟失重后股静脉P-V曲线向容积变化比增大的方向移动(同对照组比较P<0.01),模拟失重21d组较10d组移动更明显(P<0.01)。加载、卸载时,模拟失重21d组的P-V二次抛物线方程式系数B1,B2的值犤加载时为(3.6±1.6)10-2,(3.3±2.8)×10-4;卸载时(4.2±1.8)10-2,(4.6±3.4)×10-4〗显著高于对照组犤加载时为(1.3±0.6)10-2,(0.4±0.3)×10-4;卸载时(1.8±1.0)10-2,(0.8±0.8)×10-4犦及模拟失重10d组犤加载时为(1.7±0.6)10-2,(0.8±0.6)×10-4;卸载时(2.1±0.6)10-2,(1.3±0.7)×10-4〗(P<0.01),模拟失重10d组的B1,B2的值和对照组相比有增加的趋势。组织学研究表明,模拟失重组股静脉内皮细胞呈立方或矮柱状并有细胞脱落,平滑肌层变薄等变化。结论:模拟失重后股静脉顺应性增加,同时股静脉管壁结构也发生明显改变。     

血管移植中不同段脐带静脉的生物力学特性研究

背景临床施行血管重建术,内径小于6mm的人工合成血管替代人体小动脉或静脉一直未获得满意的效果,因而目前小动脉及静脉代用品的研制成为亟待解决的问题.目的为脐带静脉作为小口径移植材料的临床应用提供理论依据.设计非随机分组对照研究.地点和对象实验在郧阳医学院解剖学教研室完成,对象为湖北省十堰市太和医院妇产科收集胎龄在37 40周自然分娩正常胎儿脐带静脉20例,产妇年龄在20～30岁.干预取胎儿脐带静脉20例,依胎盘端为近端,胎儿端为远端分为近、中、远3段.在生物软组织力学试验机上测定近、中、远段脐带静脉的压力-直径关系,计算出弹性模量.横断取材,冷冻切片,苏木精-伊红法染色,用计算机图像分析系统测量其几何形态学指标.主要观察指标脐带静脉的血管各相同性增量弹性模量(Einc)、血管压力-应变弹性模量(Ep)、血管容积弹性模量(Ev)、直径和壁厚.结果近、中、远段脐带静脉的Einc,Ep和Ev均随压力的上升而增大,近段3种弹性模量(Einc26.98±3.21,Ep16.58±2.12,Ev8.31±2.35)均低于远段(Einc33.20±4.21,Ep119.45±2.87,Ev9.71±1.32)(F=95.74～126.52,P＜0.05),由近段到远段呈增大趋势.中膜厚度[(0.30±0.05)mm,(0.24±0.03)mm]及直径[(3.07±0.12)mm,(2.30±0.13)mm]值从近段到远段逐渐减小(F=12.76,P＜0.01).结论脐带静脉作为小口径动脉移植的替代材料是可行的,在血管移植时,应注意选择不同段脐带静脉,使作为移植材料的脐带静脉与宿主血管材料间的生物力学特性尽量相近,以提高移植血管的远期通畅率.     

脐带静脉组织结构的定量分析评估其替代小动脉移植材料的可行性

背景长期以来,因缺乏理想的血管移植材料而制约了血管疾病的治疗效果.组织工程技术已解决了大口径人工血管替代品,但小动脉人工血管替代品一直未获得理想的材料.目的观察不同胎龄、不同段脐带静脉的几何形态和显微结构成分,以探讨脐带静脉作为小动脉移植材料的可行性.设计分组对照观察.单位郧阳医学院医用生物力学实验室.对象实验于2001-09/2004-07在郧阳医学院医用生物力学实验室完成.选择十堰市太和医院妇产科收集胎龄在24～42周自然流产或分娩的胎儿脐带50例(经产妇许可),产妇年龄在20～30岁.方法①对脐带静脉进行机械剥离,制备成脐带静脉标本.根据胎龄分为5组24～27周组7例;28～32周组7例;33～36周组8例;37～40周组20例;41～42周组8例.其中取胎龄在37～40周的脐带20例,依胎盘端为近端,胎儿端为远端分为近、中、远3段.常规石蜡包埋、切片.用苏木精-伊红染色法、Weigert法、苯胺蓝法及桔黄G法分别染组织结构、弹性纤维、胶原纤维和平滑肌.②脐带静脉图像定量分析测量管径、壁厚、内膜、中膜和外膜厚度,采用德国产Leica-Q500IW彩色图像处理系统.提取中膜平滑肌细胞核,计算机自动计数测量框内细胞核的数目和面积,然后换算出单位面积内的细胞核的数目和面积,以此作为中膜平滑肌细胞核的数密度和面密度;分别测量血管壁中膜平滑肌、胶原纤维和弹性纤维各成分的绝对面积,计算不同着色面积与测试区域整体面积之比,从而求出平滑肌、胶原纤维和弹性纤维在各血管壁中的相对含量.主要观察指标①不同胎龄脐带静脉的几何形态变化.②不同胎龄脐带静脉的显微结构成分.③不同段脐带静脉的显微结构成分.结果①不同胎龄脐带静脉的几何形态变化随胎龄增加,脐带静脉中膜厚度和外径在各胎龄组间均有显著的增加(24～27周,28～32周,33～36周,37～40周,41～42周中膜厚分别为0.186,0.203,0.237,0.264,0.268 mm,F=133.35,P＜0.01;外径分别为1.861,1.962,2.303,2.464,2.465 mm,F=37.35,P＜0.01).②不同胎龄脐带静脉的显微结构成分从24～40周,随胎龄增加,脐带静脉中膜弹性纤维含量逐渐增多,胶原纤维的含量及胶原纤维/弹性纤维比值逐渐减少.③不同段脐带静脉的显微结构成分弹性纤维的含量近段比远段多(10.16,6.36Aa%,F=5.77～12.3,P＜0.05),由近段到远段胶原纤维/弹性纤维比值逐渐增大(F=7.63～13.4,P＜0.05).结论①脐带静脉具有与普通中等动脉相似的结构,37～40周脐带静脉管壁的胶原纤维、弹性纤维含量适中,既能承载一定的应力,又有较大的扩张能力,还富含平滑肌,具备收缩能力.②在血管移植时,以选用37～40周脐带静脉为佳,且近段顺应性优于远段,可适时选用,以利于脐带静脉移植于动脉后,能很快适应动脉的力学环境,提高移植后的远期通畅率.     

脐血管解剖结构、血流参数与胎儿生长发育的关系

目的　探讨脐带血管的解剖结构和血流参数与胎儿生长发育的关系。方法　应用彩色多普勒超声测量脐带、脐动脉、脐静脉直径 ,计算横截面积。分别于脐带胎盘附着部、漂浮部、脐轮部测量血流参数 ,并进行比较。结果　孕 2 1～ 40周脐带直径 ( 1.2 5± 0 .2 1)～ ( 1.5 0± 0 .18)cm ,面积 ( 1.2 6± 0 .13 )～( 1.83± 0 .47)cm2 ;脐动脉直径 ( 0 .2 8± 0 .0 6)～ ( 0 .40± 0 .0 9)cm ,面积 ( 0 .0 6± 0 .0 3 )～ ( 0 .14± 0 .0 6)cm2 ;脐静脉直径 ( 0 .5 4± 0 .11)～ ( 0 .79± 0 .11)cm ,面积 ( 0 .2 5± 0 .0 2 )～ ( 0 .49± 0 .15 )cm2 。孕 2 5周前胎盘附着部脐动脉血流参数低于漂浮部和脐轮部 (P <0 .0 5 ) ,孕 3 6周后胎盘附着部脐动脉血流参数高于漂浮部和脐轮部 ( P <0 .0 5 ) ,2 6～ 3 5周之间 3组差别无显著性意义 ( P >0 .0 5 )。结论　正常妊娠期脐带、脐动脉、脐静脉直径和面积随孕龄、胎儿双顶径、枕额径、头围持续增长 ,脐动脉血流参数值则持续下降。随意测量脐动脉所获得的血流参数值不能精确反映胎儿宫内情况 ,胎盘附着部脐动脉血流参数值可反映胎儿生长发育状况。     

不同内容健身运动处方对男大学生血流动力流变学参数的影响

目的:探讨提高男大学生心血管功能的锻炼内容和方法,为健身运动处方在高校的应用提供实验依据。方法:研究对象为2000-09/2004-07华南师范大学的非体育专业男大学生。研制9套内容不同的健身运动处方,指导男大学生课外体育锻炼。应用AZN-Ⅱ型心血管功能测试仪测量脉搏图,连同身高、体质量、血压等参数输入计算机,自动打印出有关血流动力流变学的参数。比较锻炼前后各参数的变化。结果:8周健身运动处方锻炼后,全面锻炼1组脉压振幅系数比锻炼前增大[(2.84±1.15)比(1.99±0.84)](P<0.05),血管弹性系数加大[(0.68±0.11)比(0.48±0.16)](P<0.05),主动脉排空系数变化显著[(0.20±0.008)比(0.21±0.007)](P<0.05);篮球组血管弹性系数显著增加[(0.69±0.32)比(0.36±0.22)](P<0.05),左心室喷血阻抗减少[(0.223±0.041)kPa·s/L比(0.284±0.031)kPa·s/L](P<0.01),总血容量显著增加[(4.80±0.27)L比(4.00±0.57)L](P<0.01);排球组脉压振幅系数增加[(2.00±0.39)比(1.39±0.32)](P<0.05),总外周阻力明显减少[(87.35±29.55)kPa·s/L比(143.89±25.93)kPa·s/L](P<0.05),左心室喷血阻抗减少[(0.201±0.056)kPa·s/L比(0.276±0.031)kPa·s/L](P<0.01),总血容量增加[(4.86±0.96)L比(4.07±0.43)L](P<0.05);耐力组的     

脐带静脉组织结构的定量分析：评估其替代小动脉移植材料的可行性

碟子背景：长期以来，因缺乏理想的血管移植材料而制约了血管疾病的治疗效果。组织工程技术已解决了大口径人工血管替代品，但小动脉人工血管替代品一直未获得理想的材料。目的：观察不同胎龄、不同段脐带静脉的几何形态和显微结构成分，以探讨脐带静脉作为小动脉移植材料的可行性。设计：分组对照观察。单位：郧阳医学院医用生物力学实验室。对象：实验于2001—09／2004—07在郧阳医学院医用生物力学实验室完成。选择十堰市太和医院妇产科收集胎龄在24～42周自然流产或分娩的胎儿脐带50例（经产妇许可），产妇年龄在20-30岁。方法：①对脐带静脉进行机械剥离，制备成脐带静脉标本。根据胎龄分为5组：24～27周组7例；28～32周组7例；33-36周组8例；37～40周组20例；41～42周组8例。其中取胎龄在37—40周的脐带20例，依胎盘端为近端，胎儿端为远端分为近、中．远3段。常规石蜡包埋、切片。用苏木精-伊红染色法．Weigert法．苯胺蓝法及桔黄G法分别染组织结构、弹性纤维、胶原纤维和平滑肌。②脐带静脉图像定量分析：测量管径，壁厚．内膜．中膜和外膜厚度，采用德国产Leica—Q500IW彩色图像处理系统。提取中膜平滑肌细胞核，计算机自动计数测量框内细胞核的数目和面积，然后换算出单位面积内的细胞核的数目和面积，以此作为中膜平滑肌细胞核的数密度和面密度；分别测量血管壁中膜平滑肌．胶原纤维和弹性纤维各成分的绝对面积，计算不同着色面积与测试区域整体面积之比，从而求出平滑肌．胶原纤维和弹性纤维在各血管壁中的相对含量。主要观察指标：①不同胎龄脐带静脉的几何形态变化。②不同胎龄脐带静脉的显微结构成分。③不同段脐带静脉的显微结构成分。结果：①不同胎龄脐带静脉的几何形态变化：随胎龄增加，脐带静脉中膜厚度和外径在各胎龄组间均有显著的增加（24～27周，28～32周，33～36周，37～40周，41～42周中膜厚分别为0.186，0．203，0．237，0，264，0．268mm，F=133.35，P〈0.01；外径分别为1．861，1．962，2．303，2．464，2．465mm，F=37．35，P〈0．01）。②不同胎龄脐带静脉的显微结构成分：从24-40周，随胎龄增加，脐带静脉中膜弹性纤维含量逐渐增多，胶原纤维的含量及胶原纤维／弹性纤维比值逐渐减少。③不同段脐带静脉的显微结构成分：弹性纤维的含量近段比远段多（10，16，6．36Aa％，F=5.77～12．3，P〈0．05），由近段到远段胶原纤维／弹性纤维比值逐渐增大（F=7．63～13．4,P〈0.05）。结论：①脐带静脉具有与普通中等动脉相似的结构，37～40周脐带静脉管壁的胶原纤维、弹性纤维含量适中，既能承载一定的应力，又有较大的扩张能力，还富含平滑肌，具备收缩能力。②在血管移植时，以选用37-40周脐带静脉为佳，且近段顺应性优于远段，可适时选用，以利于脐带静脉移植于动脉后，能很快适应动脉的力学环境，提高移植后的远期通畅率。     

新生儿呼吸衰竭机械通气撤机时的肺力学研究

目的探讨新生儿机械通气撤机时肺力学指标的范围及临床意义。方法通过Bicore-CP 100呼吸功能监测仪测定32例机械通气撤机时的新生儿在CPAP模式、脱机拔管前及拔管后20 min等条件下的肺力学指标范围,根据拔管48 h内是否重新插管并分为撤机成功组与失败组。结果成功组的呼吸力学范围为:气道阻力(Rawmean)(93.7±14.3)cmH2O/(L.s)、呼吸系统顺应性(Crs)(0.65±0.09)ml/(cmH2O.kg)、患者呼吸功(WOBp)(1 589±133.2)g.cm/(min.kg);失败组为:Rawmean(98.6±15.5)cmH2O/(L.s)、Crs(0.57±0.08)ml/(cmH2O.kg)、WOBp(1 782±148.6)g.cm/(min.kg)。Crs与WOBp两组差异有显著性。Crs(0.65±0.09)ml/(cmH2O.kg),脱机成功率95.4%。撤机后拔管前两组平均WOB为(1 768±186.4)g.cm/(min.kg),Crs为(0.624±0.11)ml/(cmH2O.kg),脱机成功率为81.25%。结论肺力学的检测对新生儿呼吸机的撤离具有指导作用,特别是呼吸系统顺应性和呼吸功的检测更具有实质意义。     

早期持续微量配方奶喂养在极低体质量早产儿肠道营养中的应用研究

[目的]探讨早期持续微量配方奶喂养在极低体质量早产儿肠道营养中的应用.[方法]选取2014年1月至2016年12月在本院接受治疗的98例极低体质量早产儿为研究对象,将2014年1月至2015年6月接受持续足量常规奶喂养的49例早产儿作为对照组,其中2015年7月至2016年12月接受持续微量配方奶喂养的49例早产儿作为观察组.喂养24周后,比较两组早产儿头围、身长、体质量、日均体质量增长量、日均热卡和蛋白质摄入量以及两组早产儿喂养不耐受比例、坏死性小肠结肠炎比例及完全肠内营养时间.[结果]喂养24周后,观察组早产儿头围、身长、体质量增加量分别为(31.68±0.78)cm、(44.03±0.88)cm、(2.247±0.157)kg,明显高于对照组(30.09±0.85)cm、(42.99±0.99)cm、(2.103±0.149)kg;观察组早产儿的日均体质量增加量、日均热卡及蛋白质摄入量分别为(4.36±0.55)g/(kg·d)、(115.19±5.73)kcal/(kg·d)、(3.12±0.31)g/(kg·d),明显高于对照组(3.31±0.76)g/(kg·d)、(88.73±5.61)kcal/(kg·d)、(2.91±0.24)g/(kg·d);观察组喂养不耐受比例、坏死性小肠结肠炎比例分别为20.41％(10/49)、8.16％(4/49),明显低于对照组63.27％(31/49)、20.41％(10/49), 观察组完全全肠内营养时间为(19.11±3.10) d,明显长于对照组(14.03±5.16)d,其差异均有统计学意义(P<0.05).[结论]早期持续微量配方奶喂养能有效增加极低体质量早产儿的头围、身长及体质量,并且能增加早产儿对热卡和蛋白质的吸收,降低喂养不耐受和坏死性小肠结肠炎的发生率,值得临床推广应用.     

补充复合磷脂对力竭运动后血清酶活性的影响

目的研究递增负荷运动至力竭后血清肌酸激酶、乳酸脱氢酶的动态变化,探讨补充复合磷脂对细胞膜通透性的影响,为在运动中补充复合磷脂提供实验依据。方法10名受试者服用复合磷脂3周,分别在服用前,1,2,3周后安静时,力竭运动后和次日晨检测血清CK,LDH活性,并与10名对照组比较。结果补充复合磷脂1周进行力竭后血清CK从服用前的(5.38±0.30)μmol/(s·L)降至(3.98±0.27)μmol/(s·L),次日晨从(3.33±0.30)μmol/(s·L)降至(2.43±0.25)μmol/(s·L),其下降具有显著性差异(P<0.05);而血清LDH从服用前的(6.78±0.47)μmol/(s·L)降至(5.77±0.42)μmol/(s·L),次日晨从(4.65±0.37)μmol/(s·L)降至(3.12±0.30)μmol/(s·L),其下降同样具有显著性差异(P<0.05)。结论补充复合磷脂后血清CK,LDH降低,说明复合磷脂具有保护细胞膜结构的完整性的作用。     

Umbilical cord morphologic characteristics and umbilical artery Doppler parameters in intrauterine growth-restricted fetuses.

OBJECTIVE: To compare prenatal morphometric changes of umbilical cord components in intrauterine growth-restricted fetuses with and without abnormal umbilical artery Doppler parameters. METHODS: Consecutive singleton intrauterine growth-restricted fetuses at a gestational age of older than 20 weeks were compared with matched appropriate-for-gestational-age fetuses. Intrauterine growth restriction was defined in the presence of a sonographic abdominal circumference below the 5th percentile for gestational age at the time of sonography and a birth weight below the 10th percentile. The sonographic examination included pulsed Doppler measurements of the umbilical artery resistance index and measurements of the umbilical cord cross-sectional area and the umbilical cord vessel area. RESULTS: A total of 84 intrauterine growth-restricted fetuses and 168 appropriate-for-gestational-age fetuses were included in the study. All umbilical cord components (umbilical cord cross-sectional area, vein area, artery area, and Wharton jelly area) were smaller in the intrauterine growth-restricted fetuses. The prevalence of lean umbilical cords (cross-sectional area < 10th percentile for gestational age) was significantly higher in intrauterine growth-restricted fetuses compared with appropriate-for-gestational-age fetuses (73.8% versus 11.3%; P < .0001). A significant and progressive reduction of the umbilical vein area corresponding to the degree of umbilical artery Doppler parameter abnormality was found. The umbilical artery area was not related to the hemodynamic changes of the blood flow in the umbilical arteries. CONCLUSIONS: The proportion of lean umbilical cords was higher in intrauterine growth-restricted fetuses than in appropriate-for-gestational-age fetuses. Umbilical vein caliber decreases significantly with worsening of umbilical artery Doppler parameters.     

Effect of umbilical ring constriction on Wharton's jelly.

OBJECTIVE: The turgor of Wharton's jelly depends on osmotic and hydrostatic pressures. We tested the hypothesis that umbilical ring constriction has an impact on umbilical venous hemodynamics and thus on the volume of Wharton's jelly. METHODS: In a cross-sectional study of 237 low-risk singleton pregnancies, the cross-sectional area of the fetal end of the umbilical cord was determined using sonography at 20-41 weeks of gestation. The inner area of the two arteries and the vein was also measured and subtracted from the cord area to calculate the area of Wharton's jelly. Based on the Bernoulli equation, the degree of vein constriction at the umbilical ring was assessed using the blood velocity increment at the abdominal inlet. Regression analysis and SD-score statistics were used to construct mean values and to assess the effects. The dataset was also analyzed for gender-specific effects. RESULTS: The umbilical cord cross-sectional area increased with gestational age during the period 20-31 weeks, remaining essentially stable thereafter. The Wharton's jelly increased with gestational age from 20 until 31-32 weeks of gestation and remained at the same level for the rest of the pregnancy. At mid-gestation, on average 70% of the cord cross-sectional area was occupied by Wharton's jelly; at 31 weeks and later this value was 60%. Umbilical vein constriction was associated with reduced umbilical cord cross-sectional area and Wharton's jelly in female fetuses (P = 0.0007 and P = 0.003, respectively), but not in male fetuses. CONCLUSIONS: Under physiological conditions, umbilical ring constriction affects umbilical vein hemodynamics, with corresponding effects on the umbilical cord cross-sectional area and the amount of Wharton's jelly. Interestingly, the effects are gender-specific.     

The effect of vascular constriction on umbilical venous pulsation.

OBJECTIVES: Umbilical venous pulsation is an important sign of hemodynamic compromise, but is also found under normal physiological conditions. Mathematical modeling suggests that vascular compliance is a determinant for pulsation, and we tested this by studying velocity pulsation at three sites on the umbilical vein. METHODS: In a cross-sectional study of 279 low-risk pregnancies (20-40 weeks' gestational age) blood flow velocity in the umbilical vein was determined before, within and after the umbilical ring in the fetal abdominal wall, and the incidence and magnitude of pulsation (the difference between the maximum and minimum velocity during a pulse, and pulsatility index) were noted. Based on the fact that the vessel cross-sectional area is an important determinant of compliance, we measured the diameter and time-averaged maximum velocity to reflect variation in diameter and compliance at the three sites. RESULTS: The incidence of umbilical venous pulsation was higher at the umbilical ring in the abdominal wall (242/279, 87%, 95% CI 82-90) than in the cord (43/198, 22%, 95%CI 16-27) or intra-abdominally (84/277, 30%, 95% CI 25-36) (P < 0.001). When pulsation was observed intra-abdominally, the pulsatility was not different from that at the umbilical ring (P = 0.16). However, the lowest pulsatility was found in the cord vein (P < 0.0001), where the largest vein diameter was found. CONCLUSION: The high incidence of venous pulsation at the umbilical ring where diameter and compliance are low supports the suggestion that local compliance is an important factor influencing pulsation in fetal veins.     

Sonographic umbilical vessel morphometry and perinatal outcome of fetuses with a lean umbilical cord

PURPOSE: This study was undertaken to assess whether changes in umbilical cord vessel morphometry are associated with an increased risk of adverse perinatal outcome among fetuses with a lean umbilical cord on sonography. PATIENTS AND METHODS: A total of 160 fetuses with a sonographically lean umbilical cord (cross-sectional area below the 10th percentile for gestational age) after 20 weeks of gestation were enrolled. The cross-sectional areas of the umbilical cord and its vessels were measured. Outcome variables investigated were perinatal death, admission to the neonatal intensive care unit, intrauterine growth restriction, and 5-minute Apgar score. RESULTS: The proportions of perinatal death (1/96 versus 6/64, p < 0.05) and admission to the neonatal intensive care unit (17/96 versus 22/64, p < 0.05) was significantly higher among fetuses with an umbilical vein area below or equal to the 10th percentile for gestational age than among those with an umbilical vein area greater than the 10th percentile. No differences were found in the proportions of perinatal death, neonatal intensive care unit admission, 5-minute Apgar score < 7, and intrauterine growth restriction when fetuses with umbilical vein areas below or equal to the 10th, the 5th, and the 2.5th percentiles for gestational age were compared. No difference was found in the umbilical artery area and Wharton's jelly area among the groups. CONCLUSION: Among fetuses with a sonographically lean umbilical cord, a significant relationship exists between an umbilical vein area below or equal to the 10th percentile and an adverse neonatal outcome.     

产前超声对胎儿脐动脉栓塞的诊断价值

目的:探讨产前超声诊断胎儿脐动脉栓塞的临床意义。方法:对2015年1月-2019年5月在本院超声检查发现一支脐动脉栓塞,并于本院分娩或引产共7例胎儿的超声图像及妊娠结局等进行回顾性分析。结果: 7例胎儿20-24周超声检查均为双脐动脉,均于28周后（28-30周）发现一支脐动脉栓塞,并于分娩后诊断脐动脉血栓,4例于分娩后诊断脐带过度扭转。超声表现其中4例为一支脐动脉内可见实性回声改变。1例为一支脐动脉内径减小继发脐动脉栓塞, 2例28周后超声诊断为单脐动脉,未显示脐动脉内血栓。5例活产,其中3例早产;2例胎死宫内。4例胎儿宫内生长受限,3例胎儿大小符合孕周。结论:脐动脉栓塞胎儿并发症和病死率高,严重影响胎儿预后,与不良妊娠结局密切相关,孕晚期超声检查应高度警惕有无脐动脉栓塞的发生,一经确诊,密切监测胎儿情况,及时终止妊娠,能有效地降低围产儿的死亡率并改善预后 。     

Prenatal diagnosis of a lean umbilical cord: a simple marker for the fetus at risk of being small for gestational age at birth.

OBJECTIVE: The purpose of this study was to investigate whether the prenatal diagnosis of a 'lean' umbilical cord in otherwise normal fetuses identifies fetuses at risk of being small for gestational age (SGA) at birth and of having distress in labor. The umbilical cord was defined as lean when its cross-sectional area on ultrasound examination was below the 10th centile for gestational age. METHOD: Pregnant women undergoing routine sonographic examination were included in the study. Inclusion criteria were gestational age greater than 20 weeks, intact membranes, and singleton gestation. The sonographic cross-sectional area of the umbilical cord was measured in a plane adjacent to the insertion into the fetal abdomen. Umbilical artery Doppler waveforms were recorded during fetal apnea and fetal anthropometric parameters were measured. RESULTS: During the study period, 860 patients met the inclusion criteria, of whom 3.6% delivered a SGA infant. The proportion of SGA infants was higher among fetuses who had a lean umbilical cord on ultrasound examination than among those with a normal umbilical cord (11.5% vs. 2.6%, p < 0.05). Fetuses with a lean cord had a risk 4.4-fold higher of being SGA at birth than those with a normal umbilical cord. After 25 weeks of gestation, this risk was 12.4 times higher when the umbilical cord was lean than when it was of normal size. The proportion of fetuses with meconium-stained amniotic fluid at delivery was higher among fetuses with a lean cord than among those with a normal umbilical cord (14.6% vs. 3.1%, p < 0.001). The proportion of infants who had a 5-min Apgar score < 7 was higher among those who had a lean cord than among those with normal umbilical cord (5.2% vs. 1.3%, p < 0.05). Considering only patients admitted in labor with intact membranes and who delivered an appropriate-for-gestational-age infant, the proportion of fetuses who had oligohydramnios at the time of delivery was higher among those who had a lean cord than among those with a normal umbilical cord (17.6% versus 1.3%, p < 0.01). CONCLUSION: We conclude that fetuses with a lean umbilical cord have an increased risk of being small for gestational age at birth and of having signs of distress at the time of delivery.     

First-trimester umbilical cord diameter: a novel marker of fetal aneuploidy.

OBJECTIVE: To compare the umbilical cord diameter at 10-14 weeks of gestation of chromosomally normal and abnormal fetuses. METHODS: In a consecutive series of women, who were undergoing routine sonographic evaluation at 10-14 weeks of gestation, umbilical cord diameter and nuchal translucency were measured. Reference ranges for umbilical cord diameter according to gestational age and crown-rump length were constructed. Fetal karyotype was obtained at chorionic villus sampling, amniocentesis or at delivery in newborns with features suspicious for chromosomal abnormalities. RESULTS: During the study period, 784 patients met the inclusion criteria. Of these, a fetal or placental chromosomal abnormality was present in 17 cases. The mean umbilical cord diameter increased with gestational age (r = 0.41, P < 0.001).The proportion of fetuses with an umbilical cord diameter above the 95th centile was higher in the presence of fetal or placental chromosomal abnormalities than in normal fetuses (5/17 vs. 39/767, P < 0.01). Among fetuses with an abnormal fetal or placental karyotype, nuchal translucency was above the 95th centile for gestational age in 10 cases.When only fetal chromosomal abnormalities were considered (n = 14), the combined detection rate was 85.7%(12/14). CONCLUSIONS: Sonographic assessment of the umbilical cord in early gestation appears to identify a subset of fetuses at increased risk of chromosomal abnormalities.     

Doppler sonographic study of fetal brachial and umbilical artery blood flow during pregnancy

PURPOSE: The purpose of this study was to evaluate the fetal brachial artery resistance index (RI), its changes throughout gestation, and its relationship to the umbilical artery RI. METHODS: One hundred fifty-four sonographic examinations of the brachial and umbilical arteries in 71 fetuses were performed between 12 and 40 weeks' gestational age in 71 women with normal pregnancies. For each week of gestational age, the mean, standard deviation, range, and t-distribution 95% confidence interval of the fetal brachial artery RI were calculated. RESULTS: The fetal brachial artery RI, although relatively lower at the beginning of gestation, showed a pattern of high resistance, with a slight increase until term, whereas the fetal umbilical artery RI decreased progressively. CONCLUSIONS: The brachial artery RI is high in normal fetuses with good oxygenation. Umbilical artery RIs showed a progressive decrease until the end of term.