胎心监测方法及临床价值

胎心监测是评估胎儿宫内状况的重要措施,通过胎心监测获得的信息有助于及早发现胎儿宫内缺氧并及时干预,但随着胎儿监护技术的广泛使用和种类多样化,过度监护导致过度干预等问题日渐显露。本文对不同类型的胎心监测方法及其临床价值进行讨论。     

胎心率监测对产前诊断脐带位置异常的意义

对２６２８例脐带位置异常的胎心率监测结果进行分析，发现脐带位置异常者胎心率监测阳性率为８１．６６％，假阴性率为１８．３４％。阳性组中有１６８０例出现可变性减速，占６３．９３％。分析发现，Ｖ型、Ｕ型和Ｗ型波为多见，共１２０６例占４５．８９％，此类波型以脐带受压并伴有胎儿宫内缺氧时为多见。提出了脐带位置异常的特异性胎心率波型及诊断标准，并观察其分娩后胎儿发育情况、脐带位置、羊水是否污染及新生儿Ａｐｇａ     

计算机分析胎心率

介绍计算机分析产前胎心率的原则，胎心率参数与胎儿状态间的关系，对此传统的识图方法，计算分析胎心率可提供客观的准确的胎心率读数，解决了观察者之间识图不一致的问题。计算机化的胎儿监护用于高危儿监测很有希望。在胎儿监测的参数中，胎儿变异是胎儿窘迫和胎儿酸中毒的最好预测指标。     

产时胎心监测的判读

胎心监护是目前了解胎儿宫内情况和胎儿储备能力的重要方法。正确解读产时监护图形,对减少新生儿惊厥、脑瘫、分娩期死亡、预测新生儿酸中毒,以及减少不必要的阴道助产和剖宫产等非常重要。     

孕晚期胎心电子监护出现间歇正弦曲线的临床意义

目的 探讨孕晚期胎心电子监护(CTG)出现间歇正弦曲线的临床意义.方法 对2002年1月至2010年12月在暨南大学第二临床医学院行产前CTG出现正弦曲线的48例孕33～41周孕妇的临床资料进行回顾性分析,其中存在正弦曲线基线特点并持续时间≥10 min不能缓解的21例为持续组,存在正弦曲线基线特点且持续时间＜10 min的27例为间歇组,随机选择同期CTG正常的76例孕妇为对照组.胎头娩出后,取脐动脉血测定血气及血红蛋白水平;新生儿住院期间行常规神经系统检查,确诊新生儿脑损害;比较分析各组新生儿结局的差异.结果 (1)新生儿并发症:间歇组新生儿窒息、羊水Ⅲ度胎粪污染和贫血发生率分别为63%(17/27)、33%(9/27)、63%(17/27),对照组分别为1%(1/76)、4%(3/76)、3%(2/76),两组比较,差异均有统计学意义(P＜0.05);持续组分别为67%(14/21)、52%(11/21)、76%(16/21),与间歇组比较,差异无统计学意义(P＞0.05).(2)新生儿血气结果:脐动脉血pH＜7.0的发生率间歇组为18%(5/27),持续组为52%(11/21),对照组为0,3组分别比较,差异均有统计学意义(P＜0.05).(3)新生儿脑损害及死亡:新生儿脑损害发生率和围产儿死亡率间歇组分别为48%(13/27)、11%(3/27),持续组分别为81%(17/21)、43%(9/21),对照组均为0,3组分别比较,差异也均有统计学意义(P＜0.05).结论 孕晚期间歇正弦曲线和持续正弦曲线均是胎儿严重贫血的特征性图形;间歇正弦曲线的发生预示胎儿可能存在比较严重的宫内缺氧.

Abstract：

Objective To investigate clinical significance of intermittent sinusoidal feial heart rate at third trimester.Methods From Jan 2002 to Dec 2010,48 pregnant women at 33 to 41 gestational weeks undergoing electronic fetal heart rate(FHR)monitoring presented with intermittent sinusoidal FHR in Department of Obstetrics and Gynecology,Second School of Clinical Medicine,Jinan University were enrolled in this retrospective study.Twenty-one cases were categorized into continuous group(i.e.with sinusoidal feature and a constant duration≥10 minutes).while the other 27 cases were categorized iuto intermittent group(i.e.with a duration＜10 minutes).In the mean time.76 normal cases were chosen randomly matched as control group.Blood gas and hemoglobin were measured in umbilical artery after fetal head delivery.General neurological system examination were performed in those fetus in hospitalization.The outcome of those fetuses was compared.Results (1)Neonatal complications:the rate of asphyxia,meconium-stained amniotic fluid and fetal anemia were 63%(17/27),33%(9/27)and 63%(17/27)in group of intermittent sinusoidal FHR,which were significantly higher than 1%(1/76),4%(3/76),3%(2/76)in control group(P＜0.05).When compared with 67%(14/21),52%(11/21),76%(16/21)in group of continuous sinusoidal,the statistical difierence were not observed(P＞0.05).(2)Blood gas in neonate:the rates of pH less than 7 were 18%(5/27)in intermittent group,52%(11/21)in continuous group and 0 in control group,which all reached statistical difference among those three groups(P＜0.05).(3)Brain damage and death:the rates of brain damage and death were 48%(13/27)and 11%(3/27)in intermittent group,81%(17/21)and 43%(9/21)in continuous group,and 0 in control group,which all showed significant difference between them(P＜0.05).Conclusion Intermittent and continuous sinusoidal FHR are typical graphics of severe fetal anemia at third trimester.Intermittent sinusoidal FHR is indicative of serious fetal hypoxia.     

孕晚期胎心电子监护出现间歇正弦曲线的临床意义

Objective To investigate clinical significance of intermittent sinusoidal feial heart rate at third trimester.Methods From Jan 2002 to Dec 2010,48 pregnant women at 33 to 41 gestational weeks undergoing electronic fetal heart rate(FHR)monitoring presented with intermittent sinusoidal FHR in Department of Obstetrics and Gynecology,Second School of Clinical Medicine,Jinan University were enrolled in this retrospective study.Twenty-one cases were categorized into continuous group(i.e.with sinusoidal feature and a constant duration≥10 minutes).while the other 27 cases were categorized iuto intermittent group(i.e.with a duration＜10 minutes).In the mean time.76 normal cases were chosen randomly matched as control group.Blood gas and hemoglobin were measured in umbilical artery after fetal head delivery.General neurological system examination were performed in those fetus in hospitalization.The outcome of those fetuses was compared.Results (1)Neonatal complications:the rate of asphyxia,meconium-stained amniotic fluid and fetal anemia were 63%(17/27),33%(9/27)and 63%(17/27)in group of intermittent sinusoidal FHR,which were significantly higher than 1%(1/76),4%(3/76),3%(2/76)in control group(P＜0.05).When compared with 67%(14/21),52%(11/21),76%(16/21)in group of continuous sinusoidal,the statistical difierence were not observed(P＞0.05).(2)Blood gas in neonate:the rates of pH less than 7 were 18%(5/27)in intermittent group,52%(11/21)in continuous group and 0 in control group,which all reached statistical difference among those three groups(P＜0.05).(3)Brain damage and death:the rates of brain damage and death were 48%(13/27)and 11%(3/27)in intermittent group,81%(17/21)and 43%(9/21)in continuous group,and 0 in control group,which all showed significant difference between them(P＜0.05).Conclusion Intermittent and continuous sinusoidal FHR are typical graphics of severe fetal anemia at third trimester.Intermittent sinusoidal FHR is indicative of serious fetal hypoxia.     

孕晚期胎心电子监护出现间歇正弦曲线的临床意义

Objective To investigate clinical significance of intermittent sinusoidal feial heart rate at third trimester.Methods From Jan 2002 to Dec 2010,48 pregnant women at 33 to 41 gestational weeks undergoing electronic fetal heart rate(FHR)monitoring presented with intermittent sinusoidal FHR in Department of Obstetrics and Gynecology,Second School of Clinical Medicine,Jinan University were enrolled in this retrospective study.Twenty-one cases were categorized into continuous group(i.e.with sinusoidal feature and a constant duration≥10 minutes).while the other 27 cases were categorized iuto intermittent group(i.e.with a duration＜10 minutes).In the mean time.76 normal cases were chosen randomly matched as control group.Blood gas and hemoglobin were measured in umbilical artery after fetal head delivery.General neurological system examination were performed in those fetus in hospitalization.The outcome of those fetuses was compared.Results (1)Neonatal complications:the rate of asphyxia,meconium-stained amniotic fluid and fetal anemia were 63%(17/27),33%(9/27)and 63%(17/27)in group of intermittent sinusoidal FHR,which were significantly higher than 1%(1/76),4%(3/76),3%(2/76)in control group(P＜0.05).When compared with 67%(14/21),52%(11/21),76%(16/21)in group of continuous sinusoidal,the statistical difierence were not observed(P＞0.05).(2)Blood gas in neonate:the rates of pH less than 7 were 18%(5/27)in intermittent group,52%(11/21)in continuous group and 0 in control group,which all reached statistical difference among those three groups(P＜0.05).(3)Brain damage and death:the rates of brain damage and death were 48%(13/27)and 11%(3/27)in intermittent group,81%(17/21)and 43%(9/21)in continuous group,and 0 in control group,which all showed significant difference between them(P＜0.05).Conclusion Intermittent and continuous sinusoidal FHR are typical graphics of severe fetal anemia at third trimester.Intermittent sinusoidal FHR is indicative of serious fetal hypoxia.     

胎心监护与其他生物物理指标的关系

自 2 0世纪 70年代胎心监护广泛应用于临床以来 ,由于胎心监护能够分辨出胎心瞬时的变化 ,并可连续动态监护 ,为临床提供了一种较为灵敏的监测胎儿心脏活动的方法。自其问世以来将胎儿死亡率从 3‰降至 0 5‰[1] 。但随着胎心监护临床研究的进一步深入 ,对其应用 30年来的调查发现 ,胎心监护在未明显改善胎儿预后的同时却大大的增加了剖宫产率。因此 ,近年来对其临床应用价值争议较多。目前多数专家认为 ,胎儿的心脏活动受神经、体液、物理、化学等内外环境的影响 ,因此异常图形的出现也不单单是缺氧所致 ,单凭胎心监护出现的异常图形来作…     

妊娠中晚期胎心率电子监护的现状与发展

胎心率电子监护是公认较为理想的监测胎儿官内状况的方法，在足月及近足月胎儿的管理中应用广泛，在妊娠中晚期（28～37周）胎儿监护中应用较少。妊娠中晚期胎心率与足月及近足月胎儿胎心率之间存在着较大的差异，在判断该期的胎心率电子监护图形时，不能完全按照足月胎儿的诊断标准，应有自己的诊断标准。     

Evaluation of fetal heart monitoring in the first stage of labor

Objective : To evaluate the usefulness of continuous electronic fetal heart rate (FHR) monitoring in the first stage of labor. Methods : A total of 814 pregnant women in labor without identifiable risk factors was divided into two groups. In group A (468 cases), continuous FHR monitoring began in the earliest phase of the first stage of labor (cervical dilatation &#104 4 cm), while in group B (346 cases) it began when the cervical dilatation was > 4 cm. Initial FHR tracings were normal in all 814 cases. The fetal monitoring findings were analyzed at 10-min intervals, and comparisons were made between the two groups concerning FHR findings and their correlation with the state of the newborns. Results : No significant difference was found between the two groups in the incidence of repetitive variable decelerations (1.9% and 1.7%, respectively); sporadic variable decelerations (9.2% and 8.7%, respectively); persistent repetitive late decelerations that resulted in Cesarean section (1.1% and 1.4%, respectively); or sporadic late decelerations (8.3% and 8.1%, respectively). One newborn from each group required intensive neonatal care. Conclusions : The same tracing sufficiency of fetal stress was observed in the two groups. However, the manner of labor supervision in group B seemed to be more beneficial, because of greater maternal comfort, a lower necessity for personnel, lower consumption of cardiotocographic materials and the possibility of labor induction for more women. Since fetal monitoring is widely used, it is preferable to start continuous FHR monitoring when the dilatation of the cervix approximates 4-5 cm (second phase of the first stage of labor) without risk of fetal loss.     

第二产程胎心监护异常标准化评判和处理

电子胎心监护由于操作简便、无创、结果实时确切,已成为产科临床应用最广泛的胎儿监护手段。但目前在对电子胎心监护图形的解读上尚存在许多争议,如何根据监护结果做出正确的临床决策也未达成一致意见。文章介绍了最新的电子胎心监护图形标准化定义,解读其原理及标准化的处理方法。     

Incidence of maternal tachycardia during the second stage of labor: a prospective observational cohort study

Objective: To our knowledge, this is the largest prospective study reporting on maternal heart rate (MHR) levels in laboring women (30 patients), and maternal tachycardia that is a potential risk factor in fetal monitoring confusion. Our objective was to analyze a large population of contiguous laboring patients and to assess the MHR levels attained during the second stage.

Methods: We performed a prospective study that analyzed MHR levels of second-stage laboring patients evaluating numerous predisposing maternal conditions. Univariate and stepwise multivariate logistic regression analysis were performed.

Results: A total of 1105 contiguous patients were analyzed and 33.9% had a sustained MHR ≥100; 18.8% had an MHR ≥110; and 9.1% had an MHR ≥120. Multivariate analysis of all potential predisposing maternal conditions did not reveal any specific variable as uniformly significant for predicting maternal tachycardia across all levels of analysis.

Conclusions: The incidence of maternal tachycardia in the second stage of labor is common. We recommend that if the MHR is ≥100 during labor, the simultaneous maternal and fetal heart rate (FHR) monitoring will be used to minimize the potential for fetal monitoring confusion and risking poor fetal outcome if the fetus is in distress.     

第一产程异常胎心监护图形与新生儿结局的关系

目的　探讨第一产程异常胎心监护图形与新生儿结局的关系。方法　回顾分析 2 0 0 2年 8月至 2 0 0 3年 6月在我院足月单胎头位分娩产妇 ,第一产程中胎心率 (FHR)异常图形 2 1 7例 (观察组 )和FHR正常图形的2 6 9例 (对照组 )的临床资料。结果　第一产程异常FHR图形的发生率为 4 4 7% ,常见类型为轻度变异减速(6 4 5 % )、基线变异减弱 (2 1 6 % )和轻度心动过速 (1 2 0 % )。晚期减速、基线变异减弱和重度变异减速是导致新生儿窒息的危险因素。观察组羊水过少 (5 1 % )、脐带缠绕 (2 2 6 % )、羊水粪染 (1 0 6 % )、新生儿窒息 (6 5 % )、新生儿转入NICU(1 0 1 % )的发生率和剖宫产率 (31 8% )明显高于对照组 (P <0 0 5 )。结论　第一产程异常FHR图形的发生率较高 ,其中晚期减速、基线变异减弱、重度变异减速与新生儿窒息的发生相关 ,其他图形可在严密监护下继续试产     

Continuous fetal heart rate monitoring in patients with preterm premature rupture of membranes undergoing expectant management

Objective.?Continuous fetal heart rate (FHR) monitoring is considered by some as necessary to the expectant management of patients with preterm premature rupture of membranes (PPROM). No data exist to support this premise, and liability may be incurred if such an order cannot be practically carried out. The purpose of our study is to evaluate the performance of prolonged FHR monitoring in terms of the completeness of recorded tracings.

Methods.?A retrospective cohort study was performed between 2004 and 2006 in a tertiary care hospital on patients being expectantly managed with PPROM at 24–34 weeks of gestation. Forty-seven singleton gravidas with a physician order of continuous external FHR monitoring were included. Exclusion criteria were evidence of labour, chorioamnionitis or FHR abnormalities that prompted delivery. FHR tracings during the prolonged monitoring period were reviewed.

Results.?The study cohort was monitored for a duration of 321–2272 min (mean 970 min). In total, 28.3% (95% confidence interval 23.8–33%) of the tracing did not show a legible recording. Gestational age is negatively correlated with the proportion of absent tracing, whereas body mass index is positively correlated. There is no significant difference in the absent signal proportion between the first half of the monitoring period and the second half or between day and night.

Conclusions.?In patients with PPROM being expectantly managed, a significant proportion (28.3%) of the FHR tracing was not recorded as ordered. This suggests that ‘continuous’ prolonged external fetal monitoring may not be practically feasible and alternative monitoring approaches should be considered.     

Limitations of autocorrelation in fetal heart rate monitoring

Fetal heart rate monitors that use autocorrelation of the ultrasonic fetal signal usually produce a cleaner fetal heart rate record than that obtainable with conventional ultrasonic fetal monitors. However, since the autocorrelation function will emphasize any periodic signal originating from the fetus or the mother, in clinical situations the resultant fetal heart rate tracing may contain spurious data. To illustrate the limitations of the autocorrelation technique in fetal monitoring, we compared the autocorrelated ultrasound fetal heart rate records from 23 patients in active labor with the simultaneously recorded direct scalp fetal electrocardiogram tracings. The results indicate that every hour of recording contained, on the average, five instances in which data were missing (range, 0 to 13), four in which data were added (range, 0 to 23), and seven instances in which data were absent for greater than 1 minute (range, 0 to 26). The potential problem of misinterpretation of autocorrelated fetal heart rate data is discussed.     

Antenatal evaluation of FHR accelerations associated with fetal movements

A retrospective comparative study of two definitions of the non-stress testing employing two and four accelerations associated with fetal movements in 20-min observation in 304 high risk pregnant women was evaluated. It was shown that four accelerations or more are no more predictive of good outcome than two accelerations during the same period. On the other hand a non-reactive test is significantly more predictive of poor outcome when two acceleration definition was employed. It was shown in cases with good outcome that the reactivity of the non-stress test increases with gestational age and that this test is invalid prior to the 33rd week of gestation.     

Intrapartum fetal heart rate monitoring in cases of cytomegalovirus infection

OBJECTIVE: Several studies have shown that abnormal intrapartum fetal heart rate patterns are the results from pre-existing fetal brain damage. We evaluated intrapartum fetal heart rate pattern of cytomegalovirus-infected fetuses and correlated the patterns with neurologic outcomes. STUDY DESIGN: Between 1991 and 2001, there were 20 cytomegalovirus-infected fetuses. We selected 40 fetuses as control subjects that were matched for gestational age and birth weight. Fetal heart rate was interpreted according to the guidelines of the National Institute for Child and Human Development. The incidence of abnormal fetal heart rate pattern and umbilical blood gases were compared between both groups. We also investigated the factors that contributed to abnormal fetal heart rate pattern in the cytomegalovirus group. RESULTS: Nonreassuring fetal heart rate patterns (prolonged deceleration and recurrent late deceleration) were observed in 8 of 20 fetuses (prolonged deceleration, 7 fetuses; recurrent late deceleration, 1 fetus) in the cytomegalovirus group and in 3 of 41 fetuses (prolonged deceleration, 1 fetus; recurrent late deceleration, 2 fetuses) in the control group (P<.05, Fisher test). Baseline fetal heart rate variability was minimal in 4 of the 7 prolonged deceleration cases in the cytomegalovirus group. Umbilical pH <7.1 was found for 1 fetus in the cytomegalovirus group. The average umbilical arterial pH values were similar in both the groups. In the cytomegalovirus group, there were no differences in the incidence of contributing factors between 8 fetuses with abnormal fetal heart rate pattern (prolonged deceleration and recurrent late deceleration) and 8 fetuses with no change. There were 3 fetuses with cerebral palsy: 2 fetuses in the no change group and 1 fetus in the prolonged deceleration group. Antigenemia was positive exclusively in 4 cases with abnormal fetal heart rate pattern (P<.05). CONCLUSION: Cytomegalovirus-infected fetuses are more likely to show abnormal intrapartum fetal heart rate patterns than low-risk control fetuses, which suggests that the perinatal detection of cytomegalovirus is necessary to distinguish hypoxic-ischemic encephalopathy.     

The need for a new outlook on labor monitoring

Fetal heart rate monitors, including the newer pulse-oximetry and STAN monitors, are designed to detect fetal distress that affects less than 1% of women in labor. Non-progressive labor is a much more common disorder than fetal distress, with approximately 50% of women in labor requiring oxytocin. Current technology assessing labor progress is subjective and inaccurate. There is a need for objective and accurate technology to measure labor progress and the effect it may have on managing labor and, specifically, non-progressive labor.     

Fetal heart rate decelerations following the administration of meperidine-promethazine during labor

A deceleration response lasting up to 7 min was observed in 53 fetuses (out of 1910 studied) following the administration of 75 mg meperidine and 25 mg promethazine intravenously to the mothers during labor. Thirty-six of these fetuses reacted with baseline tachycardia following the deceleration with or without loss of baseline variability. Seven fetuses showed a variable deceleration pattern and six fetuses reacted with a late deceleration pattern following the first deceleration. Two newborns from the group showing a late deceleration patten were delivered with an apgar score below 7 in 5 min. The probable mechanisms and significance of these changes are discussed.