[The variability of fetal heart rate response to the reduction of uterine blood flow in anaesthetized and unanaesthetized pregnant sheep].
The variation of the fetal heart rate (FHR) and blood pressure (BP) response to a definite hypoxic stress has been investigated in 3 unanaesthetized and 8 anaesthetized near term pregnant sheep. Uterine blood flow (UBF) was reduced by inserting an inflatable balloon into the maternal aorta in 33 experiments. By inflation of the balloon blood flow was reduced to zero for 5-60 sec. The response on fetal heart rate an systolic and diastolic blood pressure has been measured. The lag time of the response was estimated. Following the reduction of uterine blood flow fetal heart rate fell and the blood pressure rose. The fall of FHR and the rise of fetal systolic and diastolic BP was correlated to the duration of flow reduction. There was however a wide variation of the FHR and BP response to a definite duration of flow reduction which was also dependent on the application of anaesthesia. A relationship between the oxygen saturation at control and the FHR and BP response could not be established. From this experiment it may concluded that the application of anaesthetics reduce the FHR and BP response. In addition the duration and the fall of the FHR is not good measure for estimating the severity of fetal hypoxia.
D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure; D005260:Female; D005318:Fetal Heart / Q000502:physiology*; D006339:Heart Rate; D011247:Pregnancy; D012039:Regional Blood Flow; D012756:Sheep; D014599:Uterus / Q000098:blood supply*
Die variabilität der fetalen Herzfrequenzreaktion auf die Reduktion der uterinen Durchblutung.