彩超对胎儿大脑中动脉与脐动脉血流动力学的相关性研究

目的:探讨彩超对胎儿大脑中动脉(MCA)与脐动脉(UA)血流动力学之间的关系.方法:检查分析300例中、晚孕胎儿的MCA和UA的血流动力学参数,研究其间的关系.结果:(1)随着孕龄的增加,MCA和UA的峰值流速与舒张末期流速比值(S/D),阻力指数(RI),搏动指数(PI)均相应减小,MCA的各血流参数均相应大于UA的各血流参数(P＜0.01),(2)不论孕龄如何变化,MCA和UA的S/D、RI、PI关系密切,均呈直线正相关(P＜0.01),(3)收缩期峰值流速(PSV),舒张末期流速(EDV)相关性不明显(P>0.05).结论:UA血流动力学异常是造成脑血流动力学异常的重要因素,进一步证明了检测胎儿UA血流动力学变化对评价胎儿宫内生长发育的重要意义.     

Doppler changes in the main fetal brain arteries at different stages of hemodynamic adaptation in severe intrauterine growth restriction.

OBJECTIVE: To evaluate changes in the temporal evolution and regional distribution of arterial brain Doppler parameters in relation to different stages of hemodynamic adaptation in fetuses with severe intrauterine growth restriction (IUGR). METHODS: Thirty-six fetuses with severe IUGR ( 2 SD) were evaluated longitudinally with pulsed Doppler ultrasound at four different hemodynamic stages: Stage 1 (n = 36), mean UA-PI > 2 SD or absent UA end-diastolic flow; Stage 2 (n = 34), abnormal middle cerebral artery (MCA) PI (mean < 2 SD); Stage 3 (n = 30), reversed UA end-diastolic flow; Stage 4 (n = 12), absent or reversed atrial flow in the ductus venosus. In addition, 36 normally grown fetuses were studied for comparison. PI and time-averaged maximum velocity (TAMXV) in the MCA and the anterior cerebral (ACA), pericallosal (PER) and posterior cerebral (PCA) arteries were measured. RESULTS: In IUGR fetuses, PI values from all arteries were significantly reduced at Stage 2. At Stages 3 and 4, ACA-PI and PCA-PI did not change further, whereas MCA-PI and PER-PI showed a slight increase. In the ACA, MCA and PER, TAMXV in Stage 2 increased significantly. In Stages 3 and 4, ACA and PER-TAMXV remained unchanged, whereas MCA-TAMXV showed a slight decrease, mirroring the PI values. PCA-TAMXV values were similar to controls at all stages. CONCLUSION: In IUGR fetuses, the brain arteries differ in the magnitude and time sequence of Doppler parameters in relation to systemic hemodynamic adaptation, suggesting the existence of regional brain redistribution processes.     

Is Doppler prediction of anemia effective in the growth-restricted fetus?

OBJECTIVE: To evaluate the utility of middle cerebral artery (MCA) and umbilical artery (UA) Doppler to predict anemia in intrauterine growth restricted (IUGR) fetuses. METHODS: Fetuses with an abdominal circumference < 5th percentile had UA and MCA Doppler prior to delivery. The UA pulsatility index (PI), MCA PI, ratio between the MCA/UA PI (cerebroplacental ratio, CPR) and MCA peak systolic velocity (PSV) were measured. A complete blood count was determined from a peripheral venous sample drawn at delivery. Anemia was defined as a hemoglobin value of < 13 g/dL. MCA PSV Z-scores (standard deviation from gestational age mean using references ranges by Mari et al. and Kurmanavicius et al.) were related to hemoglobin using linear regression analysis. In addition, UA absent end-diastolic velocity (AEDV), brain sparing (MCA PI > 2 SDs below gestational age mean), low CPR (> 2 SDs below gestational age mean) and an elevated MCA PSV (> 2 SDs) were evaluated for their predictive accuracy for anemia. RESULTS: Of 97 IUGR neonates 23 were anemic (23.7%). The MCA PSV was significantly related to hemoglobin using either reference range (Mari et al., F = 22.1577, Kurmanavicius et al., F = 21.8188, P < 0.001, respectively). However, using categorical cut-offs as well as regression analysis none of the Doppler parameters could be identified to provide clinically useful prediction of anemia. CONCLUSION: Parameters of MCA and UA vascular impedance and MCA PSV are significantly related to anemia in IUGR neonates. Despite this relationship the predictive accuracy is unacceptable for the clinical application in the setting of IUGR. Altered cardiovascular dynamics in IUGR fetuses may be responsible for this effect.     

Effect of antenatal glucocorticoid therapy on arterial and venous blood flow velocity waveforms in severely growth-restricted fetuses.

OBJECTIVE: To study the effects of antenatal glucocorticoid (betamethasone) therapy on blood flow velocity waveform patterns in the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV) in severely intrauterine growth-restricted (IUGR) fetuses. METHODS: Fifty-five severely IUGR fetuses at 24-34 weeks of gestation were included in the study. The effect of antenatal glucocorticoid administration on Doppler findings in the UA, MCA and DV was studied using two statistical approaches, namely paired sample analysis and multilevel analysis. RESULTS: There were no effects of betamethasone on the pulsatility index (PI) of the vessels studied. The only changes noticed during the 14 days of observation were a gradual decrease of PI in the MCA, an increase in the UA-PI/MCA-PI ratio and an increase in the DV-PI. These changes with time may be explained by a progressive and gradual deterioration of the fetal condition. CONCLUSION: Antenatal glucocorticoids (betamethasone) do not affect fetal Doppler waveform patterns of the UA, MCA and DV in severely IUGR fetuses.     

Middle cerebral artery blood flow velocities and pulsatility index and the cerebroplacental pulsatility ratio: longitudinal reference ranges and terms for serial measurements.

OBJECTIVES: To establish reference ranges suitable for serial assessments of the fetal middle cerebral (MCA) and umbilical (UA) artery blood flow velocities, pulsatility index (PI) and cerebroplacental pulsatility ratio and to provide terms for calculating conditional reference intervals suitable for individual serial measurements. METHODS: This was a longitudinal study of 161 singleton pregnancies. Using Doppler ultrasound, MCA and UA blood velocities and PI were determined three to five times at 3-5-week intervals over a gestational age range of 19-41 weeks. Polynomial regression lines for the 95th, 50th and 5th percentiles were calculated for the peak systolic velocity (PSV), time-averaged maximum velocity (TAMXV), PI and cerebroplacental ratio. Terms for calculating conditional reference intervals were established. RESULTS: Based on 566 observations our new longitudinal reference ranges for fetal middle cerebral PSV, TAMXV and PI provided terms for calculating conditional reference intervals (i.e. predicting expected 95% confidence limits based on a previous measurement), and correspondingly for the cerebroplacental ratio (n = 550). The reference ranges were at some variance with those of previous cross-sectional studies. The narrow 95% confidence limits for the 5(th) and 95(th) percentiles ensured reliable ranges. CONCLUSIONS: We have established longitudinal reference ranges appropriate for the serial assessment of MCA blood velocities and PI and cerebroplacental ratio. Particularly the terms for calculating conditional ranges based on a previous observation make this system more appropriate for longitudinal monitoring than are cross-sectional data.     

脐带绕颈胎儿脐动脉及大脑中动脉超声血流参数的特点及与胎儿宫内窘迫的相关性分析

目的探讨脐带绕颈胎儿脐动脉(UA)及大脑中动脉(MCA)超声血流参数的特点及与胎儿宫内窘迫的相关性。方法将106例胎儿脐带绕颈孕妇、100例正常孕妇分别纳入脐带绕颈组、非脐带绕颈组。根据不同孕周、是否发生胎儿宫内窘迫对脐带绕颈组孕妇进行再次分组,分别为28~36周组(52例)、≥37周组(54例);宫内窘迫组(28例)、非宫内窘迫组(78例)。比较各组UA、MCA的RI、PI、S/D。分析UA、MCA超声血流参数与胎儿宫内窘迫的相关性。结果脐带绕颈组UA、MCA的RI、PI、S/D均高于非脐带绕颈组(P<0.05)。28~36周组UA、MCA的RI、PI、S/D均低于≥37周组(P<0.05)。宫内窘迫组UA的PI、S/D高于非宫内窘迫组,MCA的RI、PI、S/D高于非宫内窘迫组(P<0.05)。Logistic回归分析结果显示,UA、MCA的PI、RI、S/D与胎儿宫内窘迫存在明显相关性(P<0.05)。结论脐带绕颈胎儿UA、MCA超声血流参数(RI、PI、S/D)均高于非脐带绕颈胎儿,且孕晚期更为突出,UA及MCA的RI、PI、S/D与胎儿宫内窘迫呈高度相关。     

Fetal hemodynamics evaluated by Doppler velocimetry in the second half of pregnancy

The objective of our study was to assess fetal hemodynamics by Doppler velocimetry during the second half of pregnancy. We carried out a longitudinal study on 33 normal fetuses between the 22nd and 38th weeks of gestation. Doppler velocimetry was performed in the aorta, suprarenal (SRA) and infrarenal (IRA) segments, middle cerebral artery (MCA) and umbilical artery (UA), on the basis of fetal peak systolic velocity (SV), end-diastolic velocity (DV) and resistance index (RI). We used a sample volume of 1 mm, a wall filter of 50 to 100 Hz, a 5 degrees to 19 degrees insonation angle in the MCA and UA, and below 60 degrees in the SRA and IRA. Between the 22nd and 38th weeks of gestation, SV and DV increased in all fetal arteries (p<0.05), but SV decreased in the UA from 52.5 to 46.2 cm/s between the 34th and 38th gestational weeks (p<0.05). The RI was unchanged in the SRA and throughout most of the gestational weeks in the IRA (p>0.05), but decreased from 0.69 to 0.56 in the UA (p<0.05). In the MCA, it decreased from 0.85 to 0.75 between the 26th and 38th gestational weeks (p<0.05). In conclusion, the volume of blood flow in the fetal organs necessary for their development is related to increased SV and DV and to decreased RI. The Doppler velocimetry measurements for normal fetuses could be compared with those for fetuses in high-risk pregnancies.     

Doppler assessment of fetal aortic isthmus blood flow in two different sonographic planes during the second half of gestation.

OBJECTIVE: To compare the reliability of Doppler blood flow measurements of the fetal aortic isthmus (AoI) according to whether the sampling plane is obtained from the traditional longitudinal aortic arch (LAA) view or the more recently described three vessels and trachea (3VT) view of the fetal upper mediastinum. METHODS: Doppler blood flow measurements of pulsatility index (PI), resistance index (RI), peak systolic (PSV), end-diastolic (EDV) and time-averaged maximum (TAMXV) velocities were performed in the AoI of 40 fetuses between 24 and 36 weeks of gestation. All measurements were sampled in two different sonographic planes of the AoI: the LAA view, at a few millimeters beyond the origin of the left subclavian artery, and the 3VT view, just before the V-shaped junction of the aortic and ductal arches. All scans were performed by the same observer. The reliability of Doppler blood flow measurements was assessed by calculating intraclass correlation coefficients (ICCs) and limits of agreement between the two different sonographic sites evaluating the AoI. RESULTS: Mean values of PI, RI, PSV, EDV and TAMXV were similar in the LAA and 3VT views. The PI and vascular velocities were reliably measured from both sonographic sites. ICCs for variability of measurements were 0.78, 0.63, 0.63, 0.60 and 0.55 for PI, RI, PSV, EDV and TAMXV, respectively. Limits of agreement revealed minimal disagreement between the two sites of evaluation of the AoI for all measurements. CONCLUSIONS: On the basis of our observations, Doppler blood flow measurements across the fetal AoI can be reliably obtained from both the 3VT and the traditional LAA sonographic views. Since the transverse upper thoracic 3VT plane is achievable in most fetal positions, Doppler study of the AoI appears to be easier than expected.     

彩色多普勒超声观察不同孕周正常胎儿动脉血流的价值

目的：探讨不同孕周胎儿肾动脉（RA）、脐动脉（UA）、大脑中动脉（MCA）血流参数的变化情况,确定正常胎儿RA、UA、MCA血流参考值,并分析RA、UA、MCA血流参数与孕龄的关系。方法选取2013年1～12月在该院行产前检查的185例孕周为4～41周的正常单胎孕妇为研究对象,采用彩色多普勒超声测量胎儿 RA、UA、MCA的阻力指数（RI）、搏动指数（PI）、收缩期峰值流速（PS）及收缩期峰值流速与舒张末期流速比值（S/D）。结果随着孕周的增加,胎儿RA、UA、MCA中PS值显著增加,而RA、UA中RI、PI、S/D值显著减少。经相关性分析可知,RA、UA、MCA中RI、PI、S/D与孕周呈负相关性（P＜0．05）,而RA、UA、MCA中PS与孕周呈正相关性（P＜0．05）。结论应用彩色多普勒测量不同孕周胎儿RA、UA、MCA血流动力学参数能有效了解胎儿颅脑循环、胎盘循环及全身血流循环状态。通过建立正常胎儿血流参数参考范围可为超声预测胎儿宫内生长情况提供参考依据。     

脉冲多普勒超声对胎儿不同妊周脐带及脑循环动态变化的研究

目的，探讨不同妊周胎儿脐血流及脑血流的变化规律。方法，对４２２例妊娠２１～４２周正常产妇，用脉冲多普勒超声测量其胎儿脐带动脉（ＵＡ）、大脑中动脉（ＭＣＡ）之ＲＩ（阻力指数）与ＰＩ（搏动指数）。结果与结论，ＲＩ与ＰＩ的变化高度一致（ｒ＝０．９７８）（ｐ＜０．００１）。ＵＡ两指数在妊娠２１周时最高，此后逐渐下降至足月（Ｐ＜０．００１）。ＭＣＡ两指数从２１周起先缓慢上升，２９周时达高峰，此后迅速下降至足月（ｐ＜０．００１）。ＵＡ的ＲＩ、ＰＩ与ＭＣＡ的ＲＩ、ＰＩ之比值，从妊娠２１周起迅速下降，２９～３４周间维持较低水平，以后缓慢上升，到妊娠足月时仍明显低于妊娠２１周时水平（Ｐ＜０．００１）。     

Fetal adrenal and middle cerebral artery Doppler velocimetry in high-risk pregnancy.

OBJECTIVES: Animal studies have shown that hypoxic fetuses redistribute their blood flow, giving preferential supply to the brain, heart and adrenal glands. The aim of this study was to establish whether blood velocity waveforms in the human fetal adrenal artery and middle cerebral artery showed signs of redistribution of fetal circulation in high-risk pregnancy, and to analyze the relationship between signs of such redistribution and the outcome of pregnancy. METHODS: Fetal middle adrenal artery and middle cerebral artery waveforms were recorded between 27 and 41 weeks of gestation in 102 pregnancies complicated by pregnancy-induced hypertension. Signs of fetal adrenal-sparing were deemed present when the pulsatility index (PI) fell below the fifth percentile of the normal range. Signs of fetal brain-sparing were deemed present when the cerebral artery PI was below the mean -2 SD of the normal range and the cerebroplacental PI ratio was < 1.08. RESULTS: Signs of adrenal sparing were found in 64 cases and brain sparing in 32 cases. Fetal adrenal sparing was strongly associated with adverse perinatal outcome; all perinatal mortality cases showed signs of adrenal sparing. There was a significant positive correlation between the fetal adrenal artery PI and umbilical arterial and venous pH. CONCLUSIONS: Signs of adrenal sparing are frequent in high-risk pregnancies. Adrenal artery velocimetry may be a useful procedure for fetuses at risk for hypoxemia.     

Middle cerebral artery peak systolic velocity: a new Doppler parameter in the assessment of growth-restricted fetuses.

OBJECTIVE: The aims of this study were to determine if there is a relationship between middle cerebral artery (MCA) peak systolic velocity (PSV) and perinatal mortality in preterm intrauterine growth-restricted (IUGR) fetuses, to compare the performance of MCA pulsatility index (PI), MCA-PSV and umbilical artery (UA) absent/reversed end-diastolic velocity (ARED) in predicting perinatal mortality, to determine the longitudinal changes that occur in MCA-PI and MCA-PSV in these fetuses, and to test the hypothesis that MCA-PSV can provide additional information on the prognosis of hypoxemic IUGR fetuses. METHODS: This was a retrospective cross-sectional study of 30 IUGR fetuses (estimated fetal weight < 3(rd) percentile; UA-PI > 95% CI) in which the last MCA-PI, MCA-PSV and UA values were obtained within 8 days before delivery or fetal demise. Among the 30 fetuses, there were 10 in which at least three consecutive measurements were performed before delivery and these were used for a longitudinal study. MCA-PSV and MCA-PI values were plotted against normal reference ranges and were considered abnormal when they were above the MCA-PSV or below the MCA-PI reference ranges. RESULTS: Gestational age at delivery ranged between 23 + 1 and 32 + 5 (median, 27 + 6) gestational weeks. Birth weight ranged from 282 to 1440 (median, 540) g. There were 11 perinatal deaths. Forward stepwise logistic regression indicated that MCA-PSV was the best parameter in the prediction of perinatal mortality (odds ratio, 14; 95% CI, 1.4-130; P < 0.05) (Nagerlke R(2) = 31). In the 10 fetuses studied longitudinally, an abnormal MCA-PI preceded the appearance of an abnormal MCA-PSV. In these fetuses, the MCA-PSV consistently showed an initial increase in velocity; before demise or the appearance of a non-reassuring test in seven fetuses, there was a decrease in blood velocity. The MCA-PI presented an inconsistent pattern. CONCLUSIONS: In IUGR fetuses, the trends of the MCA-PI and MCA-PSV provide more clinical information than does one single measurement. A high MCA-PSV predicts perinatal mortality better than does a low MCA-PI. We propose that MCA-PSV might be valuable in the clinical assessment of IUGR fetuses that have abnormal UA Doppler.     

彩色多普勒超声对宫内发育迟缓胎儿动静脉的血流动力学研究

目的应用彩色多普勒超声检测宫内发育迟缓(IUGR)胎儿动静脉的血流动力学参数。方法测量胎儿静脉导管和脐静脉的血流量,计算静脉导管(DV)分流率;测量胎儿脐动脉、大脑中动脉(MCA)、肾动脉的搏动指数(PI)、阻力指数(RI)及脐动脉收缩期最大流速与舒张末期流速的比值(S/D),结果进行对比分析。结果与对照组比较,IUGR组胎儿脐动脉的PI、RI、S/D及肾动脉的RI显著增高,MCA的PI、RI及S/D显著减低,DV分流率显著增加,差异均有统计学意义(P<0.05)。结论彩色多普勒超声通过综合监测胎儿血流动力学变化,可以全面、客观地评价胎儿的供血情况,预测胎儿宫内缺氧和IUCR情况。     

彩色多普勒超声检测胎儿脐动脉及大脑中动脉血流频谱对预测宫内窘迫的临床意义

目的探讨运用彩色多普勒检测胎儿脐动脉(UA)及大脑中动脉(MCA)血流频谱相关数值对预测胎儿宫内窘迫的临床意义。方法选取2013年9月至2015年3月随机分层抽取行中晚期孕检孕妇44例,其中健康孕妇组35例,宫内窘迫孕妇组11例,应用彩色多普勒超声检测上述两组胎儿UA及MCA的阻力指数(RI)、血流搏动指数(PI)、收缩期与舒张期流速比(S/D)。结果与健康孕妇组相比,宫内窘迫孕妇组胎儿UA的RI、PI、S/D明显增高,而MCA各血流频谱指标明显下降,差异均有统计学意义(P0.05)。结论通过检测中晚期妊娠胎儿UA及MCA各血流频谱的指标有助于发现胎儿宫内窘迫的发生,为提高围产质量提供检查手段。     

Fetal ductus venosus, middle cerebral artery and umbilical artery flow responses to uterine contractions in growth-restricted human pregnancies.

OBJECTIVE: To explore fetal ductus venosus (DV) flow velocity changes relative to umbilical artery (UA) blood flow and brain-sparing flow (BSF) during uterine contractions. METHODS: Forty-five term fetuses suspected of having growth restriction were exposed to an oxytocin challenge test (OCT) with simultaneous Doppler velocimetry in the UA, middle cerebral artery (MCA) and DV. Basal BSF was defined as a MCA-to-UA pulsatility index (PI) ratio of < 1.08, and de novo BSF as a decrease in MCA-PI of > or = 1 SD (equivalent to a value of 0.24 units) during the OCT. RESULTS: Basal DV flow velocities were lower in the BSF group (n = 7) than they were in the non-BSF group (n = 38). During the OCT, DV flow velocity parameters changed in neither group but MCA-PI decreased in the non-BSF group. A crude de novo BSF was not associated with DV flow velocity changes, but when UA-PI changes were considered, a serial relationship was found between decreased UA-PI, increased DV flow velocity, and decreased MCA-PI. When UA-PI increased, the MCA-PI still decreased (though not significantly) but DV flow velocity parameters remained unchanged. CONCLUSIONS: Established fetal BSF is associated with low DV flow velocities, but in an acute sequence there might be two contrasting courses along which BSF develops: one with an increase and one with a decrease in the UA vascular flow resistance. In the former situation the DV flow velocity increases, while in the latter situation the role of the DV in the acute redistribution of fetal blood flow is unclear.     

Abnormal fetal cerebral and umbilical Doppler measurements in fetuses with intrauterine growth restriction predicts the severity of perinatal morbidity

PURPOSE: This prospective study was performed to determine if the ratio of the middle cerebral artery (MCA) S/D ratio (ratio of peak systolic blood flow velocity to diastolic velocity) to the umbilical artery (UA) S/D ratio (MCA/UA S/D ratio) predicts the degree of neonatal morbidity in fetuses suspected of having intrauterine growth restriction (IUGR). METHODS: Sixty-one fetuses were identified prospectively by sonography as having an estimated fetal weight below the 10th percentile for gestational age. The 61 fetuses underwent Doppler sonography in the third trimester and then were stratified into 3 groups based on the MCA/UA S/D ratio: group A, MCA/UA S/D ratio > 1.0 (controls; n = 37); group B, MCA/UA S/D ratio < or = 1.0 (intracerebral blood flow redistribution; n = 16); and group C, reversed or absent UA diastolic flow (n = 8). Outcome variables assessed included gestational age at delivery, birth weight, UA pH, mode of delivery, respiratory distress syndrome requiring intubation, and intracranial hemorrhage. RESULTS: The mean MCA/UA S/D ratios in groups A and B were 1.69 + /- 0.61 and 0.59 + /- 0.24, respectively (p < 0.01). The mean gestational ages at delivery for groups A, B, and C were 34.7, 33.2, and 29.0 weeks, respectively. The mean birth weights were below the fifth percentile for age for groups B and C and significantly related to the severity of abnormal Doppler findings (p < 0.01) after correction for age. Mean UA pHs were 7.25 + /- 0.01, 7.19 + /- 0.01, and 7.14 + /- 0.13 for groups A, B, and C, respectively, with significant differences between groups A and B (p < 0.05) and groups A and C (p < 0.05). Respiratory distress syndrome and intracranial hemorrhage were not associated with abnormal Doppler findings after correction for gestational age. The interval between the abnormal Doppler examination and delivery (p < 0.001) and the occurrence of fetal distress requiring cesarean section (p < 0.001) were significantly related to the severity of Doppler findings. CONCLUSIONS: In fetuses with suspected IUGR, abnormal MCA/UA S/D ratios are strongly associated with low gestational age at delivery, low birth weight, and low UA pH. Abnormal MCA/UA S/D ratios are also significantly associated with shorter interval to delivery and the need for emergent delivery.     

探讨提高多普勒超声帧频对产前胎儿大脑中动脉测量的重要性

目的 探讨提高多普勒超声帧频对测量大脑中动脉（MCA）收缩期峰值流速（PSV）和搏动指数（PI）的影响及重要性。方法 应用彩色多普勒超声检测659例孕20-40w的正常胎儿大脑中动脉（MCA）的血流频谱,测量其血流参数：收缩期峰值流速（PSV）和搏动指数（PI）,第一次测量（MCA.g）是在常规设置下进行的,第二测量（MCA.o）是在通过优化设置提高帧频的条件下进行,并将两次MCA血流参数测量结果进行比较。结果 MCA.o优化设置后的PSV、PI值明显高于MCA.g设置（P<0.001）。结论 与常规设置的超声测量技术相比,优化多普勒超声设置提高帧频,可提高胎儿MCA测量血流参数PSV和PI值,其对产前胎儿循环系统的评估起着重要作用,值得临床进一步研究,并调整当前MCA血流参数正常范围的参考值。     

高压氧治疗对胎儿宫内发育迟缓脑及脐动脉血流速率的影响

目的观察高压氧对胎儿宫内发育迟缓（ＩＵＧＲ）胎儿脑及脐动脉血流速率的影响。方法将４３例伴有多普勒血流异常的ＩＵＧＲ患者分为两组：高压氧组２４例,采用高压氧治疗;氨基酸组１９例,采用氨基酸治疗。测定治疗前后胎儿大脑中动脉（ＭＣＡ）、脐动脉（ＵＡ）血流速率以及ＲＩｍｃａ和ＲＩｕａ的变化,观察妊娠足月时该指标恢复情况以及与新生儿预后的关系。结果高压氧组胎儿ＲＩｍｃａ明显上升,ＲＩｕａ明显下降;足月时,ＲＩｍｃａ、ＲＩｕａ正常转变率７０．８％,与氨基酸组比较．差异有显著性（Ｐ＜０．０５）;持续异常组新生儿低Ａｐｇａｒ评分、小于孕龄儿发生率分别为６０％和８０％,明显高于正常组（Ｐ＜０．０５和Ｐ＜０．０１）。结论高压氧治疗能有效地改善ＩＵＧＲ胎儿异常的脑及脐动脉血流速率,纠正胎儿宫内缺氧,减少低体重儿的发生。     

Middle cerebral artery blood flow velocimetry among healthy fetuses with a single umbilical artery.

OBJECTIVE: A single umbilical artery (SUA) is an independent risk factor for perinatal morbidity and mortality in healthy fetuses. The aims of the study were (1) to determine middle cerebral artery (MCA) blood flow velocimetric values among fetuses without structural or chromosomal anomalies with an SUA and to compare them with nomograms of patients with a 3-vessel cord and (2) to measure the pulsatility index (PI) of the umbilical artery among these patients. METHODS: The PI values of the MCA and umbilical arteries were determined prospectively among 98 healthy fetuses with an SUA. The PI values were compared with nomograms of patients with a 3-vessel umbilical cord. For the MCA, peak systolic velocity (PSV) was also measured. Patients carrying fetuses with intrauterine growth restriction or congenital anomalies were excluded from the study. Middle cerebral artery PI values below the fifth percentile and PSV values above the 95th percentile adjusted for gestational age were considered abnormal. RESULTS: Gestational age ranged between 22 and 37.9 weeks (median, 30.3 weeks). After adjusting for gestational age, no alterations in the MCA PI and umbilical PI were found in comparison with the normal range for a 3-vessel cord known in the literature. Middle cerebral artery PSV values were also within the normal range for gestational age in all patients. CONCLUSIONS: The MCA PI and PSV values among healthy fetuses with an isolated SUA were similar to nomograms for fetuses with a 3-vessel umbilical cord. Therefore, abnormal MCA PI and PSV values among fetuses with an SUA should be treated the same as in patients with a 3-vessel umbilical cord.     

Doppler-derived umbilical artery absolute velocities and their relationship to fetoplacental volume blood flow: a longitudinal study.

OBJECTIVES: To construct reference ranges for serial measurements of the umbilical artery (UA) absolute blood flow velocities in the second half of pregnancy and to test the hypothesis that significant associations exist between UA velocities and placental volume blood flow assessed from umbilical vein blood flow velocities and diameter. METHODS: This was a prospective longitudinal study of the umbilical circulation. UA absolute velocities and umbilical vein blood flow were measured at 4-weekly intervals between 19 and 42 weeks' gestation in 130 low-risk singleton pregnancies. A total of 511 observations were used to construct the reference ranges and assess the association between UA absolute velocities and placental volume flow using multilevel modeling. RESULTS: Both UA absolute velocities and placental volume blood flow showed a steady increase throughout the second half of pregnancy. However, the gestational age-related increase in the UA end-diastolic velocity (EDV) was greater than the corresponding increase in the peak systolic velocity (PSV). The time-averaged intensity-weighted mean velocity (TAWMV)/time-averaged maximum velocity (TAMXV) was 0.6 indicating probably not a completely parabolic velocity profile. There was a significant positive association (P < 0.00001) between UA absolute velocities and placental volume blood flow, but this association was modified by the gestational age. The intraobserver coefficients of variation for the UA PSV, EDV, TAMXV and TAWMV and placental volume blood flow were 10.17%, 16.29%, 11.46%, 18.18% and 8.61%, respectively. CONCLUSION: We have established new reference ranges for the UA absolute velocities based on longitudinal data. They show a significant association with fetoplacental volume blood flow and may have a clinical value in the assessment of the umbilical circulation.