The feasibility of using heart rate variability to detect distress
thesisposted on 15.12.2014, 10:37 by Anita Boardman
The objective of this work is to look at the feasibility of using heart rate variability analysis as a method of improving discrimination between those fetuses suffering distress and those not.;Heart rate variability analysis was applied to data acquired from rats who had undergone asphyxia for set durations of up to 7 minutes. From analysis in both the time and frequency domain, it was possible to clearly identify the occurrence of the injury. Further correlations were made between these results, pH levels and neurological assessments for the different durations of asphyxia. It was found that during and following the injury, the pH and the heart rate decrease as expected, but the overall change in heart rate variability was much more pronounced. Some interesting results were also found for the shorter durations of asphyxia which will be looked at.;Fetal heart rate data was collected before and during labour in normal patients and variability analysis of the heart rate was performed. The acquisition of heart rate data using Doppler ultrasound is discussed and comparisons made between heart rate data acquired non-invasively using Doppler ultrasound and that acquired invasively using the scalp electrode during labour. It was found that providing the ultrasound signals did not suffer greater from noise, a reasonable comparison of beat-to-heat intervals and the time domain measure of heart rate variability was possible. The application of these results is discussed.;In conclusion, it has been found that it is feasible to detect asphyxial distress in rats using the standard deviation of 30 second intervals of heart beats. It has also been possible to collect fetal heart rate data and perform a similar heart rate variability analysis however further work needs to be undertaken to find out if this is predictive of distress in the fetus during labour.