Customer Success Story: University Hospital in Tours, France

Using Stan, Feedback from the Obstetrical team of University Hospital in Tours.

Stan S31 is a fetal monitoring device which analyses the baby’s electrocardio­gram during labour and delivery. In the University Hospital of Tours (France) the Department of Obstetrics and Gynecology decided to expand the use of this device. Prof. Franck Perrotin, Head of Department, outlines why the institution has taken this decision.

Unlike conventional cardiotocographs usually used during delivery, Stan S31 not only analyses fetal heart rate, but also gives access to the fetal electrocardio­gram. “During delivery, the baby’s wellbeing is usually verified by analysing fetal heart rate,ʺ explains Prof. Franck Perrotin, Head of the Gynaecology-obstetrics Department at the University Hospital of Tours. ʺThis interpretation is very subjective, first of all because the heart rate evolves throughout labour, and also because numerous parameters, such as baseline fetal heart rate, variability or acceleration and decelerations must be analysed. Therefore, the interpretation of the same fetal heart rate pattern can vary from one professional to the other.ʺ Stan S31 can limit this variation in interpretations by allowing the professionals present in the delivery room access to other fetal wellbeing parameters via the complete fetal electrocardiogram. “For example, we are studying the changes of electrocardiograms identical to those occurring during myocardial infarction in the adult,ʺ specifies the gynae­cologist.  ʺWhen the fetus gets too little oxygen, the myocardium functions anaerobically, and the electrocardiogram changes.ʺ

Stan S31 in the first line?
In practice, the medical team of the maternity ward in the University Hospital of Tours, as is the case of all teams in French maternity wards, monitors fetal heart rate throughout the labour. The latter is, depending on the presence or absence of abnormalities, classified as ʺnormal”, “intermediate”, or “pathological”. “There are abnormalities in approximately one in two deliveries, says Prof. Franck Perrotin, but they are often linked to a simple reflex of the fetus and are only due to a lack of oxygen in the fetus in less than 40% of cases. “How do you make the right decision and make the right choice for the patient and her baby under these conditions?ʺ Stan S31 can provide additional data and therefore refine the decision-making of the medical team. “We are using Stan S31 as an adjunct when the heart rate is classified as “intermediary” or “pathological” and we suspect decreased fetal oxygen levels (hypoxia),” explains the Head of Department. The device analyses the amplitude of the QRS complex (electric wave of depolarisation of the ventricles) relative to the ampli­tude of the T wave (electric wave of repolarisation of the ventricles). This is the T/QRS ratio. “I think that the analysis of the fetal ECG is a real advantage in identify­ing perinatal asphyxia,ʺ says the physician. ʺIf the abnormality is confirmed by reading the results, a decision can be made to perform a C-section or to enhance labour.ʺ

The use of Stan S31 also makes it possible to diminish the number of C-sections performed by no longer requiring full reliance on a single abnormal warning sign, “which is one of the main objectives of our mater­nity ward,ʺ specified Prof. Franck Perrotin. ʺWe were at 21% four years ago and we managed to get to 17.5%, without increasing the rate of asphyxia in new-borns, of course. We explain this decrease by the increased use of the Stan S31.ʺ

Doubling the number of deliveries with Stan S31
From now on, the teams in Tour, which have had the Stan for 6 years, have made the decision, already two years ago, to use it more. “During the first year we used it on and off,ʺ Prof. Franck Perrotin remembers. ʺToday, our goal is to increase usage from 15 to 30% for all deliveries. For example, we wish to turn it on more systematically in certain situations where the likelihood of a heart rate anomaly is significant. I am thinking in particular of pregnant women who are hypertensive, diabetic, or who require induced labour. We have recently rewritten our protocols to increase the use of Stan S31.ʺ

Conclusive observational studies (1, 2)
Why has there been more reliance on this device in recent months? Because scientific literature has recently evolved and has suggested the importance of Stan S31 in delivery rooms. “Although certain prospec­tive randomised studies were unable to prove the superiority of Stan S31 over a simple visual analysis of fetal heart rate, several observational studies concluded that teams which regularly use the device diminish their rate of perinatal asphyxia,ʺ states Prof. Franck Perrotin. ʺThis decrease is not only due to the use of Stan S31, but it is certainly influenced by it. In any case, we are intrigued by these results.ʺ “Stan S31 is also important because it is a continuous monitoring device, unlike pH measurements in fetal blood, which require contact with the fetal scalp. The measurement only indicates the level of the acid-base balance at the moment the measurement is made. Of course, the evolution of this balance can be followed through several successive measurements, but, a heart rate pattern sometimes deteriorates very quickly and continuous monitoring of the risk of asphyxia as provided by Stan S31 is often richer in information,” concludes the gynaecologist.

Team members followed training sessions to allow them to use the device more frequently. “All the mid­wives and the physicians followed an initial training course on the use of Stan S31,ʺ remarks the Head of Department. ʺWe made this information compulsory for everyone working in the delivery room. We also organise an annual meeting and a meeting for Stan staff. The latter allows us to review the most interesting cases once every three months.ʺ

1-  Kessler J, Moster D, Albrechtsen 5. Intrapartum monitoring of high-risk deliveries with ST analysis of the fetal electro­cardio­gram: an observational study of 6010 deliveries. Acta Obstet Gynecol Scand. 2013 Jan;92(1):75-84.

2-  Norén H, Carlsson A. Reduced prevalence of metabolic aci­dosis at birth-, an analysis of established Stan usage in the total population of deliveries in a Swedish district hospital. Am J Obstet Synecol. 2010 Jun;202(6):546.e1-7.

Clémence Lamirand – April 2013

Main characteristics of Stan S31
Stan S31 is a device for monitoring the fetal heart rhythm and analysing the ST segment of the fetal ECG (Stan stands for ST Analysis). It may be able to reduce the incidence of serious metabolic acidosis and limit the number of C-sections.

The maternity ward in the University Hospital of Tours in figures
The labour ward in the University Hospital of Tours, a referral level 3 University Maternity ward, performs approximately 4,000 deliveries per year among the 30,000 births in the Centre region. Four of the 8 delivery rooms are equipped with Stan S31. A team of 14 physicians, 90 midwives, and 117 orderlies work there (not including paediatricians and anaesthetists).

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