Computer evaluation of internal versus external FHR monitoring in the minutes preceding delivery

Ayres-de-Camlos, D.; Bemardes, J.; Reynolds, Arlene; Saraiva, J.; Santos, Celso Luiz Gonçalves dos; Pereira-Leite, L.

doi:10.1016/s0020-7292(00)86311-0

Cited by 2 publications

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“…The effect of FHR acquisition mode on computed linear and nonlinear FHR parameters is still largely unknown. While differences between internal and external monitoring have been documented, these were not evaluated regarding computerized indices (Fukushima et al 1985), they were analysed at a very low frequency rate (Lawson et al 1983), or did not assess the influence on linear frequency domain and nonlinear FHR indices (Ayres- de-Campos et al 2000b).…”

Section: Introductionmentioning

confidence: 99%

Internal versus external intrapartum foetal heart rate monitoring: the effect on linear and nonlinear parameters

et al. 2006

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The effect of foetal heart rate (FHR) acquisition mode on linear and nonlinear parameters is still largely unknown. In 33 normal labouring women, FHR signals were acquired simultaneously by an external ultrasound sensor applied to the maternal abdomen and an internal scalp electrode, in the minutes preceding delivery. For each case, the initial and final 5, 10 and 20 min segments were analysed, considering FHR signals at a frequency of 4 Hz (the frequency at which they are transmitted by the majority of commercialized foetal monitors). Several time and frequency domain linear and nonlinear FHR indices were computed in these segments, namely mean FHR, very low frequency (VLF), low frequency (LF), high frequency (HF), approximate entropy (ApEn) and sample entropy (SampEn). Parametric confidence intervals, statistical tests and correlation coefficients were calculated in order to evaluate the effect of internal versus external FHR monitoring modes on the considered indices. The whole evaluation was repeated using FHR signals at a frequency of 2 Hz. Most time domain linear indices were similar with external and internal monitoring in the initial and final segments of the tracings. However, linear frequency domain indices were poorly correlated in the final segments and had significantly different mean values in the initial segments. Nonlinear indices were significantly different in both initial and final segments. The correlation between 4 and 2 Hz sampled parameters was high for both linear and nonlinear indices (most correlation coefficient values ranging between 0.95 and 1) but nonlinear index values were significantly higher at 2 Hz. In conclusion, the mode used to acquire FHR signals and the sampling rate employed can significantly affect most FHR indices.

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Section: Introductionmentioning

confidence: 99%

Internal versus external intrapartum foetal heart rate monitoring: the effect on linear and nonlinear parameters

et al. 2006

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Comparison of real beat-to-beat signals with commercially available 4 Hz sampling on the evaluation of foetal heart rate variability

Gonçalves

Costa

Ayres-de-Campos

et al. 2013

Med Biol Eng Comput

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Evaluation of foetal heart rate (FHR) variability is an essential part of foetal monitoring, but a precise quantification of this parameter depends on the quality of the signal. In this study, we compared real FHR beat-to-beat signals with 4 Hz sampling provided by commercial foetal monitors on linear and nonlinear indices and analysed their clinical implications. Simultaneous acquisition of beat-to-beat signals and their 4 Hz sampling rate counterparts was performed using a scalp electrode, during the last hour of labour in 21 fetuses born with an umbilical artery blood (UAB) pH ≥ 7.20 and 6 born with an UAB pH < 7.20. For each case, the first and last 10 min segments were analysed, using time and frequency domain linear, and nonlinear FHR indices, namely mean FHR, low frequency, high frequency, approximate, sample and multiscale entropy. Significant differences in variability indices were found between beat-to-beat and 4 Hz sampled signals, with a lesser effect seen with 2 Hz sampling. These differences did not affect physiological changes observed during labour progression, such as decreased entropy and linear time domain indices, and increased frequency domain indices. However, significant differences were found in the discrimination between fetuses born with different UAB pHs, with beat-to-beat sampling providing better results in linear indices and 4 Hz sampling better results in entropy indices. In conclusion, different FHR sampling frequencies can significantly affect the quantification of variability indices. This needs to be taken into account in the interpretation of FHR variability and in the development of new equipment.

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Computer evaluation of internal versus external FHR monitoring in the minutes preceding delivery

Cited by 2 publications

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Internal versus external intrapartum foetal heart rate monitoring: the effect on linear and nonlinear parameters

Internal versus external intrapartum foetal heart rate monitoring: the effect on linear and nonlinear parameters

Comparison of real beat-to-beat signals with commercially available 4 Hz sampling on the evaluation of foetal heart rate variability

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