Variable heart rate decelerations and transcutaneous Po2 during umbilical cord occlusion in fetal monkeys

摘要: Abstract In five near-term rhesus monkeys under ketamine anesthesia, fetal heart rate, blood pressure, intrauterine and transcutaneous oxygen tension (tcP o 2 ) were recorded continuously while the umbilical cord was occluded for 15 or 30 seconds. Fetal rate decreased 55 ± 19 bpm, (mean SD) 78 20 respectively, with second occlusions, tcP declined 6.0 1.6 11.5 3.3 torr, respectively. hypertension started promptly occlusion reached a maximum within 5 to 16 seconds; pressure thereafter and, in most instances, fell below baseline until began recover. 1 seconds of occlusion. changes same, attenuated when fetus pretreated 0.2 mg atropine. These findings support rapid marked initial baroreceptor response, followed by less chemoreceptor response. Thirty following occlusion, Pa had returned baseline, white still 3 7 torr indicating cutaneous vasoconstriction even though systemic normal. Relative heat output required maintain electrode temperature at 44°C did not reflect alterations skin perfusion during periods cardiovascular change.