In the European Stan Expert meeting in 2009, the interpretation of a high baseline T/QRS ratio at the start of a registration was discussed since some cases with high baseline T/QRS followed by metabolic acidosis had been encountered. The baseline T/QRS is the absolute value of the T/QRS ratio at the start of a Stan recording, and is currently only used for comparison with later changes indicating a rise in the T-wave of the fetal ECG.
The objective of this retrospective studywas to evaluate if the value of the baseline T/QRS ratio could be used to predict intrapartum asphyxia. High baseline T/QRS ratio was defined as ≥0.25 or ≥2 SD from the mean.
A total of 2459Stan recordings from two earlier published studies were included in the evaluation. The recordings were divided into three groups depending on outcome; 88.3% had an uncomplicated delivery, 8.9% ended in an operative delivery due to suspected fetal distress and 2.8% of the neonates had an adverse outcome. No statistically significant differences in mean T/QRS baseline could be identified between the three groups.
The authors state that they did not find any arguments in favour of using high baseline T/QRS at the start of the Stan recording as a predictor for adverse neonatal outcome or intervention for fetal distress. In addition they conclude that the current Stan guidelinesare still suitable, and that local Stan guidelines that are extended to include recommendations regarding high T/QRS baseline should be adjusted.