彩色多普勒超声测定窒息新生儿肠系膜上动脉、腹腔动脉血流

目的了解窒息后新生儿胃肠血流灌注动态变化。方法应用多普勒超声血流显像技术，对２２例（３０例次）窒息后新生儿于生后１、３、７天进行了肠系膜上动脉（ＳＭＡ）和腹腔动脉（ＣＡ）的血流各参数测定，并以３０例正常足月新生儿作为对照。结果窒息组患儿生后第１天、第３天ＳＭＡ、ＣＡ血流速度各参数较对照组低（Ｐ＜０．０５），并且较本组第７天各参数亦低（Ｐ＜０．０５）。ＳＭＡ血流参数的改变较ＣＡ明显。结论围生期窒息后新生儿胃肠道的血流存在低灌注现象，可能为窒息后新生儿易罹患急性胃粘膜损伤、坏死性小肠结肠炎的病理生理学基础。     

Brain superoxide anion generation during asphyxia and reventilation in newborn pigs

Superoxide anion generation during severe asphyxia and reventilation was assessed in newborn pigs. Using closed cranial windows over the parietal cortices, superoxide dismutase (SOD)-inhibitable nitroblue tetrazolium (NBT) reduction was determined during asphyxia/reventilation. Asphyxia was induced by turning off the respirator and occluding the endotracheal tube. In each animal, 2.4 mM NBT dissolved in artificial cerebrospinal fluid was placed under one window and under the opposite window, NBT (2.4 mM) plus SOD (60 U/mL) dissolved in artificial cerebrospinal fluid was used. A significant increase in SOD-inhibitable NBT reduction was observed in asphyxiated piglets (14.67 +/- 4.5 pmol/mm2 x 20 min) when compared with control piglets (2.82 +/- 1.1 pmol/mm2 x 20 min). In another group in which the animals were treated with indomethacin (5 mg/kg i.v.) before asphyxia/reventilation, there was minimal SOD-inhibitable NBT reduction. Our results indicate that superoxide anion is generated on the cerebral cortex during asphyxia/reventilation via the prostaglandin endoperoxide synthase pathway.     

窒息新生儿肾损害及一氧化氮保护作用

为了解机械通气治疗的窒息新生儿肾损害的发生情况，比较不同窒息程度与肾损害的关系。并探讨一氧化氮（NO）吸入治疗对肾脏的影响。对机械通气治疗的41例窒息新生儿（轻度窒息19例，重度窒息22例），进行回顾性分析，其中13例同时予以NO吸入治疗。结果显示：41中17例（占41．5％），有不同程度的肾损害，重度窒息患儿肾损害发生率明显高于轻度窒息患儿（P＝0．014）。予以NO吸入治疗的窒息患儿肾损害的改善较未予以NO吸入治疗者明显，9例未用NO吸入治疗的肾损害患儿在机械通气治疗后2例肾损害好转，5例无好转，另2例未随访，8例用NO吸入治疗的肾损害患儿在NO吸入治疗后肾损害好转6例，另2例未随访，提示窒息新生儿肾损害的发生率相当高，而NO吸入治疗能较明显的改善窒息后的肾损害。     

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目的了解窒息新生儿在听觉刺激诱发脑神经活动时的脑氧合代谢和脑血流量的改变。方法1998~2003年北京中日友好医院儿科选择窒息新生儿34例为窒息组,健康新生儿40名为对照组。使用近红外光谱仪,观察听觉刺激试验诱发的脑氧合血红蛋白[HbO2]、还原血红蛋白[HbH]和总血红蛋白[Hbtot]浓度的变化,并比较两组脑氧合代谢和脑血流量的改变。根据[HbO2]、[HbH]和[Hbtot]不同的变化,将氧合代谢曲线分为A([HbO2]、[HbH]和[Hbtot]均增加);B([HbO2]和[Hbtot]增加,[HbH]降低);C([HbO2]和[Hbtot]降低,[HbH]增加)3种曲线类型。结果窒息组中25例(25/34、73·5%)显示C型变化,对照组中28例(28/40、70·0%)显示A型变化,两组中A、C两型例数比较差异显著(P<0·05)。两组[HbO2]和[Hbtot]数值变化幅度比较差异显著(P<0·05)。结论窒息新生儿听觉刺激诱发相应皮层的神经活动时,显示局部脑血流量下降、氧合代谢降低,重度窒息儿更明显。     

The effect of asphyxia on gut blood flow in term neonates

Transcutaneous Doppler ultrasound measurements were made of the superior mesenteric artery of 25 term infants to correlate the intestinal blood flow with neonatal acid-base status as measured in umbilical artery blood and newborn condition as reflected by Apgar score. Compared with the babies whose umbilical artery pH was higher than 7.20 (peak systolic velocity: 84.1 cn/sn, mean velocity 48.6 cm/sn), the blood flow of superior mesenteric artery was significantly decreased in the newborn babies whose umbilical artery pH was less than 7.20 (peak systolic velocity 48.8 cm/sn, mean velocity=32.6 cm/sn). Although no such relationship existed between Apgar scores and superior mesenteric artery blood flow indices, a significant linear correlation between superior mesenteric artery blood flow and umbilical artery pH was noted. A reduction of intestinal circulation was observed during umbilical cord blood acidemia and hypoxemia.     

窒息新生儿血清胃泌素与胃酸分泌的动态观察

为探讨不同程度窒息对新生儿胃酸分泌及胃泌素水平的影响。对25例轻度窒息新生儿、20例重度窒息的新生儿于出生后1、3、7天检测血清胃泌素和胃液基础酸排量(BAO)。结果显示重度窒息组第1、3天的血清胃泌素水平明显低于轻度窒息组，而第1天胃液基础酸排量则高于轻度窒息组。结论重度窒息新生儿血清胃泌素水平较轻度窒息新生儿明显降低，而胃液基础酸排量增高，这可能是导致新生儿喂养不耐受、易致消化道出血的原因。     

Vascular compression of the duodenum in a newborn

This report describes a newborn female with extrinsic duodenal obstruction by the right colic artery, a variant of the superior mesenteric artery syndrome. The condition was succesfuully treated surgically by mobilization of the right colon and its blood supply off of the duodenum. This is a rare case of extrinsic vascular compression of the duodenum in a newborn without malrotation or a preduodenal portal vein. A review of the literature and discussion is included.     

Tetrahydrobiopterin is present in high quantity in human milk and has a vasorelaxing effect on newborn rat mesenteric arteries

Breast milk reduces the incidence of necrotizing enterocolitis (NEC). BH4 is a cofactor for endothelial NOS (eNOS). Reduced BH4 levels, or its oxidation to dihydrobiopterin (BH2), uncouple eNOS resulting in formation of reactive oxygen species (ROS) that have been implicated in the pathogenesis of NEC. We evaluated colostrum and mature breast milk, as well as infant formula, BH4 and BH2 content. In addition, we tested the BH4 effect on the newborn rat mesenteric arterial vascular tone. BH4 and BH2 content increased 3-fold in mature breast milk, when compared with colostrum (p < 0.01), without a change in their ratio. Infant formula had a negligible BH4 content and lower biopterins ratio, when compared with breast milk. eNOS is the predominant synthase isoform in newborn rat mesenteric arteries. In the presence of BH4, mesenteric arteries contracted less to thromboxane A? analog U46619 (p < 0.01) and this effect was abolished following eNOS inhibition. BH4 (10?? M) vasorelaxed the newborn rat mesenteric arteries. We conclude that when compared with infant formula, breast milk has a high BH4 content that increases as breastfeeding continues. Given its mesenteric arterial vasorelaxing effect, BH4 may play an important role in the reduced NEC incidence among breast fed infants.     

Meconium aspiration induces neuronal injury in piglets

Aim: Meconium aspiration-induced hypertensive lung injury, especially when connected with perinatal asphyxia, has been associated with brain damage. We aimed to determine the neuronal injury induced by pulmonary meconium contamination alone and with concurrent asphyxia. Methods: 36 anaesthetized and ventilated newborn piglets were haemodynamically monitored for 6 h. Seven piglets without concurrent asphyxia and seven piglets with asphyxia were instilled with a bolus of human meconium intratracheally. Seven piglets had only asphyxia and 15 piglets served as controls. The brains were studied histologically. Results: Meconium aspiration did not change systemic haemodynamics acutely, while its combination with asphyxia diminished the abrupt postasphyxic systemic hypertensive peak and resulted in a transient increase in carotid artery flow, not seen after isolated asphyxia. Systemic pressure declined after 4 h in all insulted groups, but only isolated asphyxia was associated with a sustained decrease in carotid artery flow. Arterial oxygenation remained normal, except during the acute insults. Brain examination after meconium instillation indicated neuronal injury, especially in the CA3 region of the hippocampus. Asphyxia resulted in neuronal injury in the cortical, cerebellar and hippocampal hilus regions.
Conclusion: Severe meconium aspiration itself may result in hippocampal neuronal injury.     

Transient elevation of aldosterone levels in perinatal asphyxia

Abstract We measured plasma aldosterone levels in cord blood and peripheral blood collected 18–24 h after birth in 19 asphyxiated and 19 normal term newborn infants. The asphyxiated newborn infants had significantly higher aldosterone levels in cord blood than the normal newborn infants. At 18–24 h after birth there was no difference between the groups with respect to aldosterone levels. There was a positive significant correlation between aldosterone levels and PCO₂ in cord blood by multiple linear regression analysis. There is a transient elevation of aldosterone levels in perinatal asphyxia.     

Cerebrovascular mechanisms in perinatal asphyxia: the role of vasogenic brain edema

Previous studies from our laboratory have demonstrated penetration of Evan's blue dye into the brain in profound fetal asphyxia, suggesting that vasogenic brain edema (BE) might be an immediate contributing factor in asphyxial brain injury. We modified the 125I-labeled albumin method of Pappius and McCann to quantitate vasogenic BE after acute fetal asphyxia. With 51Cr-labeled red cells to measure intravascular volume, and 125I-labeled albumin to measure total tissue plasma, the equivalent extra vascular plasma volume, i.e., vasogenic BE, was calculated. Twenty chronically prepared animals were studied, six nonasphyxiated controls and 14 asphyxiated (of which sex term animals were normotensive and five term and three premature animals were hypertensive during asphyxia). No difference in extra vascular plasma volume was found between asphyxiated and control animals in any of four brain regions. We conclude that, although blood brain barrier function might be impaired, vasogenic BE is not quantitatively significant immediately after severe fetal asphyxia.     

Comparison of the effect of asphyxia, hypoxia, and acidosis on intestinal blood flow and O2 uptake in newborn piglets

The aim of our study was to compare the effects of asphyxia and the two components of asphyxia, i.e. hypoxia and acidosis, on intestinal blood flow and oxygen consumption in anesthetized newborn piglets less than 3 days old. The first series of experiments, consisting of four groups of piglets, showed that blood flow to the proximal and distal small intestine and colon (as determined by the microsphere technique) significantly decreased after piglets were subjected to a sustained hypoxic hypoxemia (PaO2 50% of control) or asphyxia (acidosis plus hypoxia) for 90 min. A sustained acidosis (arterial pH = 7.0-7.15 for 90 min), however, decreased blood flow only to the proximal small intestine, and sham operation did not significantly alter any intestinal blood flow. All animals subjected to asphyxia and two of five of the animals subjected to hypoxia alone in this series, produced gross and microscopic intestinal lesions similar to those seen in human newborn with necrotizing enterocolitis. Acidosis alone, however, did not produce any pathologic lesions. The second series of experiments showed that the 90-min hypoxic hypoxemia decreased blood flow to both the mucosa and muscularis layers of the small intestine. The third series of experiments, consisting of four groups of piglets, determined the effects of 60-min acidosis, hypoxic hypoxemia, asphyxia, or sham operation on venous outflow and oxygen consumption of the isolated in situ terminal ileum. Acidosis or sham operation altered neither ileal blood flow nor oxygen consumption. Hypoxia or asphyxia, however, decreased ileal oxygen consumption without significantly decreasing blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)     

Asphyxia aggravates systemic hypotension but not pulmonary hypertension in piglets with meconium aspiration

Meconium aspiration and birth asphyxia are both separately connected to significant pulmonary and systemic hemodynamic changes in newborns, but, although these insults frequently coexist, their combined effects on the neonatal circulation are still controversial. To determine the pulmonary and systemic circulatory changes induced by pulmonary meconium contamination with concurrent asphyxia, 41 anesthetized and ventilated newborn piglets (10-12 d) were studied for 6 h. Eleven piglets were instilled with a bolus of human meconium intratracheally, and 10 piglets had meconium instillation with immediate induction of an asphyxic insult. Eight piglets had only asphyxia and 12 ventilated piglets served as controls. Meconium instillation (with and without asphyxia) resulted in a sustained decrease in the oxygenation, which remained, however, on the control level in the asphyxic group. Although meconium insufflation (with and without asphyxia) increased pulmonary artery pressure and vascular resistance progressively during the study period, the meconium-induced hypertensive effect was actually diminished by additional asphyxia. Asphyxia alone did not have any effect on these pulmonary hemodynamic parameters. On the other hand, whereas systemic arterial pressure and vascular resistance remained on the control level after meconium instillation alone, asphyxia (with and without pulmonary meconium insult) resulted in a sustained fall in systemic pressure already by 4 h. Our data thus indicate that although the coexisting asphyxia seems to moderate the meconium aspiration-induced pulmonary hypertensive response, this additional asphyxic insult does not affect the associated hypoxemia, but rather significantly exacerbates systemic hypotension.     

Plasma thrombomodulin level in newborn infants with and without perinatal asphyxia

To determine whether vascular endothelial damage occurs in neonates with asphyxia, we examined the plasma thrombomodulin level at birth in infants with and without asphyxia. The plasma thrombomodulin concentration in 11 asphyxiated infants was significantly elevated compared with that in 48 infants without asphyxia (38.1 vs 27.0 μg/l, p < 0.0001). The plasma thrombomodulin-to-serum creatinine ratio was also significantly elevated (0.62 vs 0.48 μg/μmol, p = 0.0005). The plasma thrombomodulin concentration and the plasma thrombomodulin-to-serum creatinine ratio in infants without asphyxia did not differ between the two types of delivery: normal vaginal delivery and elective caesarean section. Stepwise regression analysis showed the serum D-dimer concentration, plasma pH and serum creatinine concentration were significant independent variables for plasma thrombomodulin concentration, whereas base deficit, platelet count, fibrinogen concentrations and antithrombin III activity were not. Our data suggest that vascular endothelial damage might occur in asphyxiated infants.     

Cerebral blood flow velocity pattern in healthy and asphyxiated newborns: a controlled study

In a controlled study serial determinations of cerebral blood flow velocity using Doppler ultrasound and repeated real-time ultrasonographic- or computerized axial tomographic studies of the brain were performed in 17 (nearly) full-term newborns who experienced perinatal asphyxia and in 17 healthy matched controls during the first week of life. A higher cerebral blood flow velocity was found during the first 4 days of life, indicating a lower cerebrovascular resistance in the asphyxiated infants compared to the control infants. These haemodynamic changes coincided with cerebral oedema and neurological abnormalities. It is speculated that the changes in the cerebral circulation in asphyxiated infants are at least partly caused by cerebral oedema-induced increase of intracranial pressure due to severe perinatal asphyxia. Serial Doppler ultrasound investigations of the brain may be a useful non-invasive method for early detection and follow-up of the consequences of severe perinatal asphyxia.Abbreviations ACA anterior cerebral artery - AUVC area under the velocity curve - CT computerized axial tomography - EDFV end diastolic flow velocity - HIE hypoxic-ischaemic encephalopathy - PI pulsatility index - PSFV peak systolic flow velocity     

Studies on the effect of acute asphyxia on the fetal pig in utero.

8 term fetal pigs (110-112 days gestation) and one 97-day fetus were asphyxiated in utero by occlusion of the umbilical cord. Mean times to last gasp and last heart beat were 5.1 and 22.4 for term and 5.4 and 30.4 min for the 97-day fetus. Cord occlusion was followed by profound bradycardia and an increase in blood pressure which was maintained until gasping ceased. Profound acidemia, hypercapnia and hyperlactacidemia developed in all animals and values following asphyxiation were comparable with those seen in stillborn piglets. Liver and cardiac glycogen levels were lower in asphyxiated fetuses than in littermates but muscle glycogen levels were similar in both groups.     

窒息新生儿血清总胆汁酸、前白蛋白变化及其临床意义探讨

目的探讨窒息时新生儿血清总胆汁酸(TBA)、前白蛋白(PAB)变化及其临床意义。方法检测各30例轻度、重度窒息新生儿及20例缺氧缺血性脑病(HIE)新生儿的(TBA)、(PAB)、丙氨酸转氨酶(ALT)、白蛋白(ALB)水平,并设30例正常新生儿为对照。结果轻度、重度窒息儿和HIE新生儿血清TBA、PAB水平与正常儿比较差异均有非常显著性(P<0.001)窒息时血清TBA、PAB水平与Apgar评分均呈线性相关(r=0.571,-0.689,P<0.001),随病情好转血清TBA和PAB水平逐渐恢复正常。结论血清TBA和PAB是反映窒息儿肝功能损害灵敏的生化指标,动态测定血清TBA和PAB水平变化能很好地、灵敏地反映窒息儿肝脏损害情况及病情转归。     

ECG changes in asphyxia neonatorum

Twenty five asphyxiated neonates had ECG changes consistent with degree of asphyxia. Equivocal changes were found in mild asphyxia and changes suggestive of myocardial infarction were seen with severe asphyxia. In most cases, the changes reverted to normal within two weeks signifying great ability of the neonatal heart to withstand hypoxic insult. Four babies with severe asphyxia having ECG changes suggestive of acute myocardial infarction expired within 48 hours of birth.     

儿童慢性肠系膜缺血致急性肠坏死一例并文献复习

目的:探讨儿童慢性肠系膜缺血的临床特点及诊治方法,提高儿科医生对本病的诊疗水平。方法:回顾性分析首都医科大学附属北京儿童医院收治的1例12岁因慢性肠系膜缺血所致的急性肠坏死女性患儿,体重14 kg,身高115 cm,曾有6年餐后腹痛病史,以持续性腹痛3 d,伴呕吐入院。入院诊断为急性消化道穿孔。急诊行开腹探查,术中见空...     

Collateral Blood Flow in the Distal Ileum of Neonatal Piglets: A Clue to the Pathogenesis of Necrotizing Enterocolitis

Normal blood flow was measured in two regions of the ileum (distal and proximal) of normal birth weight (NBW) and low birth weight (LBW) neonatal piglets. Compensatory collateral blood flow in response to occlusion of vessels in the mesenteric vascular arcades was also measured in distal and proximal ileum of NBW and LBW neonatal piglets. Under normal control conditions the blood flow in the distal ileum of NBW piglets is reduced (40% less than proximal) and in LBW animals this reduction is greater (55% less than proximal). Both proximal and distal ileum of NBW animals but the proximal ileum only of LBW animals could mount compensatory collateral flow, whereas the distal ileum of LBW animals was unable to do so. This decompensation in LBW distal ileum may explain the predilection of NEC lesions for the distal ileum and proximal colon.