The Impact of Physiological Interpretation of Cardiotocogram (CTG) in Conjunction with Fetal ECG (STAN) on Intrapartum Emergency Caesarean Sections

Abstract

Background:The false-positive rate of the "pathological" CTG has been reported as >60%, which resulted in an exponential increase in emergency intrapartum caesarean sections for "fetal distress". Fetal ECG (ST-Analyser or STAN) was introduced into clinical practice to reduce the false positive rate of the CTG.Objective: To determine the impact of Physiological interpretation of Cardiotocogram (CTG) in Conjunction with Fetal ECG (STAN) on intrapartum emergency caesarean sections. Materials & Methods:A retrospective study at the Royal Gwent Hospital in South Wales following the introduction of STAN monitoring after training in Physiological Interpretation of CTG in 2014. Total Caesarean section rate, emergency caesarean section rate for fetal compromise (i.e., "fetal distress"), operative vaginal delivery rate and spontaneous vaginal delivery (SVD) rate were analyzed for the first 19 months after the intervention (October 2014-2016) and were compared with 2012 -September 2014).Result: There were 7977 deliveries during the 19-month period from 01 October 2014 to 30 April 2016. The average total Caesarean section rate was 23.5% and the emergency Caesarean section rate for suspected fetal compromise ("fetal distress") was 13.6%, an observed increase in the rate of spontaneous vaginal births from 63% to 71%. There was a statistically significant reduction in the intrapartum emergency caesarean sections performed for "fetal distress" immediately after the introduction of STAN following training on Physiological Interpretation of CTG from 5.57% to 2.1%. The rate of hypoxic ischaemic encephalopathy (HIE) due to CTG misinterpretation was reduced by 50% following the training on Physiological Interpretation of CTG. Conclusion:Training on physiological interpretation of the CTG before the introduction of STAN, and its use in conjunction with STAN resulted in a statistically significant reduction of intrapartum emergency caesarean section for "fetal distress", and a 50%reduction in the HIE rate due to CTG misinterpretation.

Updated NICE Cardiotocograph (CTG) Guideline: Is it Suspicious or Pathological?

“…The International Consensus Guideline on Physiological CTG interpretation produced by 44 CTG experts from 14 countries in 2018 [2] which was developed to aid interpretation of CTG traces to timely recognise intrapartum hypoxic stress is based on the identification of the combination and/or sequence of that indicate different types of fetal hypoxia, and determination of fetal response to ongoing stress (Table 2). In contrast, the recently updated NICE CTG Guideline continues to include arbitrary parameters grouped into "reassuring, nonreasoning and abnormal" "categories" and then randomly combining them to have an overall classification (Normal, Suspicious, Pathological) without any consideration of different types of fetal hypoxia or the fetal response to stress [3].…”