Pulsed wave Doppler velocimetry in the descending aorta of chronically instrumented fetal sheep.
Pulsed wave Doppler sonography was used to determine peak systolic velocity (Vpeak), mean maximum velocity (Vmean) and Pulsatility Index (PI) in the descending aorta of chronically instrumented, unanesthetized fetal sheep (days 120-130 of pregnancy). Measurements were done 1-4 days after surgery using a duplex mechanical sector scanner (4.5 MHz) and offset attached pulsed wave Doppler probe (2.25 MHz) during periods of control, intrauterine cooling and rewarming. Mean values derived from the envelope curve of maximum shift frequencies were (controls): thoracic: Vmean 60.9 +/- 9.1 cm/sec, Vpeak 118.9 +/- 17.8 cm/sec, PI 1.57 +/- 0.24; abdominal: Vmean 49.6 +/- 10.9 cm/sec, Vpeak 98.9 +/- 20.4 cm/sec, PI 1.59 +/- 0.41. Vpeak was positively correlated to arterial pressure (r = 0.23) and PI showed an inverse correlation to heart rate (r = -0.22). During cold stress (reduction of fetal core temperature by 2.7 degrees C) and consecutive rewarming Vpeak and Vmean were positively correlated to fetal core temperature and arterial pressure (r = 0.2-0.26). PI revealed a weak negative dependency from core temperature and heart rate (r = -0.19 and -0.18 respectively).
Hüneke
B
B
Department of Obstetrics and Gynecology, University Hospital Eppendorf, Hamburg, West Germany.
Schröder
H J
HJ
Carstensen
M H
MH
Leichtweiss
H P
HP
D000818:Animals; D001011:Aorta / Q000000981:diagnostic imaging* / Q000502:physiology; D001784:Blood Gas Analysis; D001794:Blood Pressure; D005260:Female; D005323:Fetal Monitoring / Q000379:methods*; D006339:Heart Rate; D011247:Pregnancy; D012016:Reference Values; D012039:Regional Blood Flow; D012044:Regression Analysis; D012756:Sheep; D014463:Ultrasonography