Intrapartum fetal surveillance: a physiological approach

Continuous utero-placental circulation, and patent umbilical blood vessels ensure an uninterrupted transfer of oxygen and nutrients to the fetus as well as clearance of metabolic waste products. The onset of labour characterized by progressive and strong uterine contractions poses a threat to fetal oxygenation as a result of collapsing the spiral arterioles traversing the myometrium to supply the placental bed, and repetitive compression of the blood vessels within the umbilical cord. Human fetuses are equipped with compensatory mechanisms to cope with transient interruptions of blood supply during labour. The ability to compensate may be blunted in cases of poor fetal reserves, increased metabolic demand (macrosomia or maternal fever), and due to non-hypoxic pathways (e.g. chorioamniontis or fetal hypovolumia-hypotension syndrome). Intrapartum fetal surveillance involves prompt recognition of the features that signal the onset of fetal decompensation on the cardiotocograph (CTG) to ensure a timely intervention to avoid hypoxic-ischaemic encephalopathy (HIE) or perinatal deaths. This article summarises a ‘physiological approach’ to the interpretation of the CTG which, in places, conflicts with other current UK guidance.     

Preservation of Denonvilliers' fascia for nerve‐sparing laparoscopic total mesorectal excision: A neuro‐histological study

Urogenital complications due to pelvic autonomic nerve damage frequently occur following rectal surgery. We investigated whether total mesorectal excision (TME) with preservation of the Denonvilliers' fascia (DVF) can effectively prevent the removal of pelvic autonomic nerves through microscopy. Twenty consecutive male patients with mid‐low rectal cancer who received TME with preservation or resection of the Denonvilliers' fascia (P and R groups, respectively) were included. Serial transverse sections from surgical specimens were studied histologically. Nerve fibers at the surfaces of the mesorectum were counted. Clinical correlation between the amount of nerve fibers removed and post‐operative sexual function was analyzed. Nerve fibers closely localized to the DVF in the R group displaying rich erectile activity (positive anti‐nNOS immunostaining). At the anterior surface of the mesorectum, the mean numbers of nNOS‐positive nerve fibers per specimen in the P group were significantly lower than the R group (3.0 ± 1.8 vs. 5.0 ± 2.3, P < 0.05). Compared to the R group, patients in the P group had higher IIEF scores and better erectile function at 3 and 6 months post‐operatively. The DVF is a key risk zone for pelvic denervation during laparoscopic TME. Preservation of the DVF can prevent the removal of autonomic nerves and protect post‐operative erectile function. Clin. Anat. 32:439–445, 2019. © 2019 Wiley Periodicals, Inc.     

两种柽柳对盐胁迫的生理生化响应

柽柳属(Tamarix chinensis L.)植物,为多年生泌盐盐生植物,是一类重要灌木植物,具有许多独特的生物、生态学特征。本研究以刚毛柽柳(T.hispida Wild)和长穗柽柳(T.elongata Ledeb)为研究对象,采用盆栽实验,开展耐盐性实验:中性盐NaCl设置0、50、100、150和200 mmoL/L 5个浓度水平,通过测定盐胁迫下两种柽柳的光合速率、蒸腾速率、游离脯氨酸含量、干重等生理指标,结果显示:刚毛柽柳和长穗柽柳均表现出较强的耐盐能力,但刚毛柽柳受NaCl胁迫的影响较小,表明刚毛柽柳耐盐性强于长穗柽柳,可作为柽柳属植物耐盐生理和分子机制研究的备选材料。     

儿童左束支区域起搏六例临床观察

目的探讨儿童左束支区域起搏(LBBAP)的安全性及有效性.方法回顾性分析2019年1月至6月于北京安贞医院小儿心脏科住院采用LBBAP方式行永久心脏起搏器植入术的6例患儿(男1例、女5例)的临床资料、起搏心电图及参数并进行随访.组间比较采用t检验.结果6例患儿年龄9~14岁,体重26~48 kg;三度房室传导阻滞5例,右室心尖起搏术后伴心功能下降1例;1例患儿心功能降低,余5例心功能均正常;QRS波时限(95±13)ms;左心室舒张末径(LVEDD)Z值为1.85±0.65.起搏心电图V1呈右束支传导阻滞样,QRS波时限(111±20)ms,与术前相比,差异无统计学意义(t=-1.610,P>0.05).起搏阈值为(0.85±0.26)V,感知(15.0±4.3)mV,阻抗(717±72)Ω.3例可记录到P电位.起搏钉至左心室激动时间为(56±5)ms,不同输出电压下数值恒定.术后超声提示电极均位于室间隔左心室心内膜下.随访无心肌穿孔、电极脱位等并发症发生,患儿术后3个月阈值、感知及阻抗分别为(0.60±0.09)V、(16.1±3.9)mV、(662±78)Ω.左心室射血分数(LVEF)降低者LBBAP术后3d恢复正常(45%比57%).术后3个月LVEDD Z值降至(1.1±0.3),较术前明显减小(t=2.383,P<0.05).结论LBBAP可实现窄QRS波起搏,接近生理性起搏,起搏参数稳定,可快速、有效地纠正长期心动过缓所致的左心扩大及长期右室心尖起搏所致的心功能低下及心脏扩大.较大年龄儿童行LBBAP近期安全性、有效性好,远期潜在风险有待进一步观察研究.