Sofia Blad

Developmental Outcome at 6.5 Years After Acidosis in Term Newborns: A Population-Based Study

OBJECTIVES: Infants who develop encephalopathy after perinatal asphyxia have an increased risk of death and adverse neurologic outcome. Conflicting results exist concerning outcome in healthy infants with metabolic acidosis at birth. The aim of the current study was to evaluate whether metabolic acidosis at birth in term infants who appear healthy is associated with long-term developmental abnormalities. METHODS: From a population-based cohort (14 687 deliveries), 78 infants were prospectively identified as having metabolic acidosis (umbilical artery pH < 7.05 and base deficit in the extracellular fluid >12.0 mmol/L). Two matched controls per case were selected. The child health and school health care records were scrutinized for developmental abnormalities. RESULTS: Outcome measures at 6.5 years of age for 227 of 234 children (97%) were obtained. No differences were found concerning neurologic or behavioral problems in need of referral action or neurodevelopmental diagnosis in comparison of control children with acidotic children who had appeared healthy at birth, ie, had not required special neonatal care or had no signs of encephalopathy. CONCLUSIONS: Infants born with cord metabolic acidosis and who appear well do not have an increased risk for neurologic or behavioral problems in need of referral actions or special teaching approaches at the age of 6.5 years.

Fetal scalp pH and ST analysis of the fetal ECG as an adjunct to CTG. A multi-center, observational study

Abstract Objective: To evaluate the relationships between scalp-pH and CTG plus ST waveform analysis of the fetal ECG (STAN) clinical guidelines as indicators of intrapartum hypoxia in term fetuses born with cord artery acidemia. Study design: Data from 6999 term deliveries monitored by the STAN® S 21 as part of an EU multi-center study on clinical implementation of the STAN methodology for intrapartum fetal surveillance were analyzed. We identified 911 cases where a scalp-pH was obtained, including 53 cases with cord artery acidemia (pH < 7.06). Lag times between ST events and scalp-pH and time to delivery were related to cord artery metabolic and respiratory acidosis and neonatal outcome. Results: 43 fetuses were identified by CTG plus ST as being in need of intervention 31 (25–46) minutes before delivery (median, 95% Cl). In five, no indications were given and in another five there were inadequate data. Fifteen cases with metabolic acidosis required special neonatal care, all 14 cases adequately monitored on STAN had indications to intervene for 19 minutes or more. In 30 adequately recorded cases, fetal blood sampling (FBS) was obtained within the last hour of labor. In 22 cases, FBS was obtained 13 (7–24) minutes after STAN guidelines had indicated abnormality and in eight no ST changes had occurred at time of FBS. The corresponding FBS data were pH 7.10 (7.01–7.15) and pH 7.21 (7.08–7.31), respectively, P = 0.01. In cases of metabolic acidosis, scalp-pH fell 0.01 units per minute after a baseline T/QRS rise was recorded during the second stage of labor. Apart from one newborn that died at 2 h from E. Coli septicemia, none of the neonates were affected neurologically. Conclusion: Cardiotocography plus ST analysis provides accurate information about intrapartum hypoxia similar to that obtained by scalp-pH.

Fetal scalp ph and ST analysis of the fetal ECG as an adjunct to cardiotocography to predict fetal acidosis in labor : A multi-center, case controlled study

Abstract Objective: To assess the relationship between scalp pH (FBS) and ST analysis in situations of acidosis with special emphasis on the timing of cardiotocography (CTG), FBS and ST changes during labor. Study design: From a European Union multicenter study on clinical implementation of the STAN methodology, 911 cases were identified where a scalp-pH had been obtained. In 53 cases, marked cord artery acidosis was found (cord artery pH<7.06) and 44 cases showed moderate acidemia at birth (pH 7.06–7.09). Comparisons were made with 97 control cases (pH≥7.20). Results: Of those cases with FHR+ST events recorded within 16 min of delivery, 61% (17/28) had a cord artery pH≥7.20. The corresponding figure for cases where STAN indications occurred for more than 16 min was 19% (13/69) (OR 6.66, 2.53–17.55, P<0.001). Out of the 121 cases with an abnormal CTG, 84 (69%) showed a cord artery pH of <7.10. STAN indicated abnormality in 83% (70 out of 84). The corresponding figure for scalp pH<7.20 was 43% (36/84). In the case of CTG changes at the start of an adequate recording STAN guidelines provided information on developing acidosis in all cases but one (16 out of 17) in the marked acidosis group. STAN guidelines indicated abnormality prior to an abnormal FBS in 14 out of 17 cases. The median duration between STAN indications to intervention and an abnormal FBS was 29 (95% CI 11–74) min. Conclusions: ST analysis, as an adjunct to CTG, identifies adverse fetal conditions during labor similar to that of FBS but on a more consistent basis. The timing of CTG+ST changes relates to the level of acidosis at birth.

The effects of intrapartum hypoxia on the fetal QT interval

Background  The morphology of the fetal ECG complex provides information on the fetal condition during labour, such as the ST segment and T‐wave configuration. We hypothesised that the intrapartum fetal QT interval may provide additional information on the condition of the fetus, as it is known that the QT interval reacts to situations of stress and exercise.

ECG and Heart Rate Variability Changes in Preterm and Near-Term Fetal Lamb Following LPS Exposure

The aim of this study is to evaluate the myocardial response in the preterm and near-term fetal lamb with infection. Chronically instrumented fetal lambs were exposed to lipopolysaccharide (LPS), and the fetal electrocardiogram (FECG) ST waveform was examined using STAN. Fetal heart rate variability (FHRV) was automatically analyzed by adapting a polynomial function to the RR sequence in the FECG. Preterm fetuses exposed to >90 ng/kg LPS died within 8 hours of LPS administration, a response not seen in near-term fetuses. In both surviving and nonsurviving preterm fetuses, cardiovascular responses were characterized by decreased arterial pressure, negative T waves, and tachycardia accompanied by an increase in FHRV. Similar changes were not observed in the near-term fetuses after LPS. The study shows that preterm lambs are more sensitive to LPS in terms of myocardial/cardiovascular response than the more mature fetuses are. High FHRV and negative ST waveform seem to characterize the LPS-induced stress response in preterm fetuses.

Change in heart rate variability in relation to a significant ST‐event associates with newborn metabolic acidosis

Objective  To find whether low‐to‐high frequency (LF/HF) ratio of fetal heart rate (FHR) variability changes in relation to a significant ST‐event during delivery, and if the change is predictive of metabolic acidosis of the newborn.

Electrocardiographic changes following umbilical cord occlusion in the midgestation fetal sheep

Background.  Clinical studies show that analysis of the fetal electrocardiographic (FECG) ST waveform at term gives important information on the myocardial response to intrapartum asphyxia. However, it is not known whether the preterm fetus responds in a similar fashion. The objective of the present study was to evaluate the FECGST response to umbilical cord occlusion in the preterm fetal sheep.

Assessment of the fetal bioprofile during labor by fetal ECG analysis

Today, the fetal bioprofile generated during labor and delivery consists of a static assessment of fetal heart rate (FHR). The stress generated by uterine activity provides a means of testing the ability of the fetus to meet the challenges of being born. FHR patterns are valuable for identifying normality, and patterns identifying fetal reactivity (variability and accelerations) are most useful for immediate fetal surveillance. Complexity becomes vast when abnormality is detected, owing to active fetal adaptation to stress and variations in the ability to cope. Thus, each fetus has its own pattern of reactions and bioprofile to be considered. The fetal ECG, forming the basis for FHR monitoring, has been shown to be a clinically useful source of information reflecting both autonomic nervous system (FHR patterns, beat-to-beat variation) and heart muscle reactivity (ST waveform changes). Automatic assessment of the ST forms the basis for the new STAN® fetal surveillance methodology, and additional decision s...

Assessment of fetal reactivity biopatterns during labour by fetal ECG analysis

Reactivity is the pattern of reactions associated with response to changes in the environment such as stress. Labour with uterine contractions hampering fetal and uterine blood flow provides significant stress and we need to improve our ability to assess fetal reactivity biopatterns during delivery. The study illustrates progress made with regard to detailed analysis of the fetal heart rate (FHR) and beat-to-beat variations (RR-intervals) as a clinical measure of fetal reactivity. A method, named residuals, is presented of using a small set of index cases to identify parameter settings which are then further evaluated in extensive database tests of 8100 cases.