Improving intrapartum surveillance: an individualised T/QRS ratio?

Objectives: To test the T/QRS ratio of the fetal electrocardiogram for norm al distribution and assess the potential value of an individualised T/QRS r atio threshold to depict abnormality in the detection of fetal compromise d uring labour. Study Design: A retrospective analysis of twenty intrapartum fetal electrocardiogram recordings obtained on the labour ward of the Queen 's Medical Centre, Nottingham. Results: In two of the twenty cases the T/QR S ratio was normally distributed. An increase in the T/QRS ratio over the 9 7.5th and 99.5th centile for 2 consecutive minutes, calculated on an indivi dual basis, would appear to discriminate best between biochemically comprom ised and non-compromised fetuses. In no case was the T/QRS ratio seen to ex ceed 0.25 for periods previously described to be related to poor outcome. C onclusion: T/QRS ratio changes with individually calculated criteria for ab normality may be of benefit in the detection of fetal compromise but the ef fect on the intervention rate remains to be established. The use of an abso lute threshold for T/QRS ratio abnormality which is based on the assumption of a normal distribution needs to be viewed with caution. (C) 2000 Elsevie r Science Ireland Ltd, All rights reserved.