When intra-partum electronic fetal monitoring becomes court business

Sadly but inevitably, the clinical fruit of all scientific research, like the profile of the Roman god Janus, presents us with two faces - one is patient benefit while the other is medico-legal vulnerability. As part of defensive medicine, there are situations where malpractice risk is minimised by actual elimination of certain high-risk procedures e.g. in the case of some neurosurgical operations. Intra-partum electronic fetal monitoring (IPEFM) is the commonest obstetric procedure in the developed world, producing valuable information of fetal well being as co-related to maternal uterine activity with a scope of guarding fetal well-being in labour. It is a prime example of the therapeutic/ legal liability duality which haunts modern Medicine.peer-reviewe

Reducing stillbirths: screening and monitoring during pregnancy and labour

<p>Abstract</p> <p>Background</p> <p>Screening and monitoring in pregnancy are strategies used by healthcare providers to identify high-risk pregnancies so that they can provide more targeted and appropriate treatment and follow-up care, and to monitor fetal well-being in both low- and high-risk pregnancies. The use of many of these techniques is controversial and their ability to detect fetal compromise often unknown. Theoretically, appropriate management of maternal and fetal risk factors and complications that are detected in pregnancy and labour could prevent a large proportion of the world's 3.2 million estimated annual stillbirths, as well as minimise maternal and neonatal morbidity and mortality.</p> <p>Methods</p> <p>The fourth in a series of papers assessing the evidence base for prevention of stillbirths, this paper reviews available published evidence for the impact of 14 screening and monitoring interventions in pregnancy on stillbirth, including identification and management of high-risk pregnancies, advanced monitoring techniques, and monitoring of labour. Using broad and specific strategies to search PubMed and the Cochrane Library, we identified 221 relevant reviews and studies testing screening and monitoring interventions during the antenatal and intrapartum periods and reporting stillbirth or perinatal mortality as an outcome.</p> <p>Results</p> <p>We found a dearth of rigorous evidence of direct impact of any of these screening procedures and interventions on stillbirth incidence. Observational studies testing some interventions, including fetal movement monitoring and Doppler monitoring, showed some evidence of impact on stillbirths in selected high-risk populations, but require larger rigourous trials to confirm impact. Other interventions, such as amniotic fluid assessment for oligohydramnios, appear predictive of stillbirth risk, but studies are lacking which assess the impact on perinatal mortality of subsequent intervention based on test findings. Few rigorous studies of cardiotocography have reported stillbirth outcomes, but steep declines in stillbirth rates have been observed in high-income settings such as the U.S., where cardiotocography is used in conjunction with Caesarean section for fetal distress.</p> <p>Conclusion</p> <p>There are numerous research gaps and large, adequately controlled trials are still needed for most of the interventions we considered. The impact of monitoring interventions on stillbirth relies on use of effective and timely intervention should problems be detected. Numerous studies indicated that positive tests were associated with increased perinatal mortality, but while some tests had good sensitivity in detecting distress, false-positive rates were high for most tests, and questions remain about optimal timing, frequency, and implications of testing. Few studies included assessments of impact of subsequent intervention needed before recommending particular monitoring strategies as a means to decrease stillbirth incidence. In high-income countries such as the US, observational evidence suggests that widespread use of cardiotocography with Caesarean section for fetal distress has led to significant declines in stillbirth rates. Efforts to increase availability of Caesarean section in low-/middle-income countries should be coupled with intrapartum monitoring technologies where resources and provider skills permit.</p

Short term fetal heart rate variation in intrauterine growth restriction

Cardiotocography (CTG), the continuous and simultaneous recording of the fetal heart rate (FHR) and the maternal contractions, is a method widely used for the assessment of fetal well-being, predominantly in pregnancies with increased risk of complications. The Oxford system, developed by Dawes and Redman and implemented in the Sonicaid Fetalcare monitor, provides a computerised analysis of the CTG (cCTG) by taking into consideration a number of numerical, computer based parameters, with Short Term Variation (STV), a measure of the micro fluctuations of the FHR, being one of the most significant ones, especially in the monitoring of fetuses with Intrauterine Growth Restriction (IUGR). The Dawes-Redman algorithm calculates the STV by dividing each minute into 16 segments, each one being 3,75 seconds long and including 7-10 fetal heartbeats, or 6-9 pulse intervals (STV16). The average pulse interval in each section is calculated and the STV16 derives from the difference of the average pulse intervals between two sections. This calculated STV16 does not, however, equal the beat-to-beat variation of the FHR. A series of important studies has demonstrated that, when monitoring fetuses with preterm IUGR, STV16 values under 3ms correlate positively with the development of metabolic acidemia and should prompt to delivery. Theoretically, measurement of the pulse interval in much smaller time fractions, so that every heartbeat would be taken into consideration (instead of one every 7-10 heartbeats), would lead to a more accurate approximation of the beat-to-beat variation with significant advantages for the antenatal monitoring of the fetus. The IntelliSpace Perinatal by Philips Medical, which measures the STV by dividing each minute into 240 segments (STV240), attempts to better approximate the beat-to-beat variation of the FHR. An effort in our department to implement the existing cut-off values of the STV16 as reference values for the new STV240 algorithm has resulted in highly abnormal findings, with STV240 values significantly below the cut-off values of the STV16. This observation led to the hypothesis, that the reference values for the STV240 should be different, and, more precisely, lower in comparison to the existing reference values for the STV16. This hypothesis was not only based on clinical observation. The discrepancy noted between the two different algorithms is also logically sound, as it is to be expected that the variation between two subsequent beats will be notably lower as the variation between 7-10 subsequent heartbeats. We therefore conducted a single-center, non-interventional, prospective clinical study in order to develop clinically relevant reference values for the STV240 and to compare the reference values for the STV240 to the ones for the STV16. At the same time, we studied the effects of RDS prophylaxis on STV240 and STV16, in order to verify if the known transient effects of corticosteroids on the STV could also be detected with the new algorithm for the STV240. A total of 228 CTG traces from 94 patients (86 singleton and 8 twin pregnancies) were registered and included in the final statistical analysis for the development of the reference values. The values of the STV240 were significantly lower in comparison to the ones of the STV16. Moreover, not only the mean values but 95% of the values for the STV240 lay beneath the existent cut-off value for the STV16. The STV240 has a relative strong, statistically significant correlation with the STV16 (r=0,646, p<0,001). A medium, although statistically significant correlation (r=0,373, p<0,001) between week of pregnancy and STV240 was documented, whereas the correlation between STV16 and week of pregnancy was negligible. A transient increase of both the STV240 and STV16 was documented in the first 24h after the first intramuscular corticosteroid administration, when compared to the STV240 and STV16 without RDS prophylaxis or at least 72h after. This was followed by a transient decrease of both the STV240 and STV16 between 24h and 72h after the first intramuscular corticosteroid injection. Our results confirmed our hypothesis and allowed us to calculate the reference values for the STV240. Of paramount importance for every clinician using the new algorithm in her or his everyday practice, is to know that the normal values for the STV240 (not only the mean value but also the 95th percentile) lie beneath the, up until now, established cut-off value for the STV16. This stresses the fact that every clinician using cCTG should be, in advance, well aware of the algorithm implemented in his cCTG monitors. Otherwise, there is the threat of unnecessary iatrogenic premature deliveries, with all relevant risks.Cardiotocographie (CTG), die kontinuierliche und gleichzeitige Aufzeichnung der fetalen Herzfrequenz (FHF) und der mütterlichen Kontraktionen, ist eine Methode, die weithin für die Beurteilung des fetalen Wohlbefindens verwendet wird, vorwiegend bei Schwangerschaften mit erhöhtem Komplikationsrisiko. Das von Dawes und Redman entwickelte Oxford-System, welches im Sonicaid Fetalcare Monitor implementiert ist, bietet eine computerisierte Analyse des CTG (cCTG) unter Berücksichtigung einer Reihe von numerischen, computerbasierten Parametern an. Kurzzeitvariation (KZV), eine Maßnahme der Mikrofluktuationen des FHF, ist einer der bedeutendsten computerbasierten Parameter, vor allem bei der Überwachung von Feten mit intrauteriner Wachstumsrestriktion (IUGR). Der Dawes-Redman-Algorithmus berechnet die KZV, indem er jede Minute in 16 Segmente unterteilt, wobei jedes 3,75 Sekunden lang ist und 7-10 fetale Herzschläge oder 6-9 Pulsintervalle (KZV16) enthält. Das mittlere Pulsintervall in jedem Abschnitt wird berechnet und die KZV16 ergibt sich aus der Differenz der mittleren Pulsintervalle zwischen zwei Abschnitten. Diese berechnete KZV16 entspricht jedoch nicht der beat-to-beat-Variation der FHF. Eine Reihe wichtiger Studien hat gezeigt, dass bei der Überwachung von Feten mit früher IUGR KZV-Werte unter 3ms positiv mit der Entwicklung einer metabolischen Azidämie korrelieren und zur Entbindung führen sollten. Theoretisch würde die Messung des Pulsintervalls in viel kleineren Zeitabschnitten, so dass jeder Herzschlag berücksichtigt wäre (statt eines alle 7-10 Herzschläge), zu einer genaueren Annäherung der beat-to-beat-Variation der FHF führen, mit deutlichen Vorteilen für die antepartale Überwachung des Fetus. Das IntelliSpace Perinatal von Philips Medical, das die KZV auswertet, indem es jede Minute in 240 Segmente teilt (KZV240), versucht die beat-to-beat Variation der FHF besser anzunähern. Ein Versuch, in unserer Abteilung, die vorhandenen cut-off-Werte der KZV16 als Referenzwerte für den neuen KZV240-Algorithmus zu implementieren, hat zu sehr auffälligen Befunden geführt, wobei die KZV240-Werte deutlich unter den cut-off- Werten der KZV16 lagen. Diese Beobachtung führte zu der Hypothese, dass die Referenzwerte für die KZV240 im Vergleich zu den vorhandenen Referenzwerten für die KZV16 niedriger sein sollten. Diese Hypothese beruht nicht nur auf der klinischen Beobachtung. Die zwischen den beiden verschiedenen Algorithmen bemerkte Diskrepanz ist auch theoretisch zu erwarten, weil die Variation zwischen zwei nachfolgenden Herzschlägen deutlich geringer als die Variation zwischen 7-10 nachfolgenden Herzschlägen ist. Wir haben daher in unserer Klinik eine nicht interventionelle, prospektive klinische Studie durchgeführt, um klinisch relevante Referenzwerte für die KZV240 zu entwickeln und diese mit denen für die KZV16 zu vergleichen. Gleichzeitig haben wir die Effekte der RDS-Prophylaxe auf KZV240 und KZV16 untersucht, um zu prüfen, ob die bekannten transienten Effekte von Kortikosteroiden auf der KZV auch mit dem neuen Algorithmus für die KZV240 nachgewiesen werden können. Insgesamt wurden 228 CTGs von 94 Patientinnen (86 Einlings- und 8 Zwillings- Schwangerschaften) registriert und in die endgültige statistische Analyse zur Entwicklung der Referenzwerte einbezogen. Die Werte der KZV240 waren im Vergleich zu der KZV16 deutlich niedriger. Darüber hinaus lagen nicht nur die Mittelwerte, sondern 95% der Werte für die KZV240 unter dem vorhandenen cut-off-Wert für die KZV16. Die KZV240 hat eine relativ starke, statistisch signifikante Korrelation mit der KZV16 (r = 0,646, p <0,001). Eine mittlere, obwohl statistisch signifikante Korrelation (r = 0,373, p <0,001) zwischen Schwangerschaftswoche (SSW) und KZV240 wurde dokumentiert, während die Korrelation zwischen KZV16 und SSW vernachlässig war. In den ersten 24h nach der ersten intramuskulären Kortikosteroidgabe wurde eine vorübergehende Zunahme sowohl der KZV240 als auch der KZV16 dokumentiert, im Vergleich zu den KZV240 und KZV16 ohne RDS-Prophylaxe oder mindestens 72h danach. Darauf folgte eine vorübergehende Abnahme sowohl der KZV240 als auch der KZV16 zwischen 24h und 72h nach der ersten intramuskulären Kortikosteroidgabe. Unsere Ergebnisse bestätigten unsere Hypothese und erlaubten uns, die Referenzwerte für die KZV240 zu berechnen. Es ist extrem wichtig für jeden Arzt, der den neuen Algorithmus in seiner alltäglichen Praxis verwendet, zu wissen, dass die Normalwerte für die KZV240 (nicht nur der Mittelwert, sondern auch die 95. Perzentile) unterhalb der bislang etablierten cut-off-Werte für die KZV16 liegen. Dies unterstreicht die Tatsache, dass bei der Interpretation der KZV des cCTGs der verwendete Algorithmus berücksichtigt werden sollte. Ansonsten besteht die Gefahr von unnötigen, iatrogenen, vorzeitigen Entbindungen mit allen damit verbundenen Risiken

Agreement and accuracy using the FIGO, ACOG and NICE cardiotocography interpretation guidelines.

INTRODUCTION: One of the limitations reported with cardiotocography (CTG) is the modest interobserver agreement observed in tracing interpretation. This study compared agreement, reliability and accuracy of CTG interpretation using the FIGO, ACOG and NICE guidelines. MATERIAL AND METHODS: A total of 151 tracings was evaluated by 27 clinicians from three centers where FIGO, ACOG and NICE guidelines were routinely used. Interobserver agreement was evaluated using the proportions of agreement (PA) and reliability with the kappa (k) statistic. The accuracy of tracings classified as "pathological/category III" was assessed for prediction of newborn acidemia. For all measures, 95% confidence intervals (95%CI) were calculated RESULTS: CTG classifications were more distributed with FIGO (9%, 52%, 39%) and NICE (30%, 33%, 37%) than with ACOG (13%, 81%, 6%). The category with the highest agreement was ACOG category II (PA=0.73 95%CI 0.70-76), and the ones with the lowest agreement were ACOG categories I and III. Reliability was significantly higher with FIGO (k=0.37, 95%CI 0.31-0.43), and NICE (k=0.33, 95%CI 0.28-0.39) than with ACOG (k= 0.15, 95%CI 0.10-0.21), however all represent only slight/fair reliability. FIGO and NICE showed a trend towards higher sensitivities in prediction of newborn acidemia (89% and 97% respectively) than ACOG (32%,), but the latter achieved a significantly higher specificity (95%) CONCLUSIONS: With ACOG guidelines there is high agreement in category II, low reliability, low sensitivity and high specificity in prediction of acidemia. With FIGO and NICE guidelines there is higher reliability, a trend towards higher sensitivity, and lower specificity in prediction of acidemia. This article is protected by copyright. All rights reserved