Rybakowski, C. and Schroder, H. and Moll, Waldemar and Cetin, E. and Huneke, B. (1995) INCREASE OF DOPPLER INDEXES IN THE LOWER ABDOMINAL-AORTA DURING INFUSION OF NITROPRUSSIDE INTO CHRONICALLY INSTRUMENTED FETAL SHEEP. JOURNAL OF MATERNAL-FETAL INVESTIGATION, 5 (1). pp. 52-56. ISSN 0939-6322
Full text not available from this repository.Abstract
Objective: The change of blood flow profiles in the lower abdominal aorta of fetal sheep during arterial hypotension was investigated. Methods: Five fetal sheep (gestational age 119-127 days) were chronically instrumented with catheters in the abdominal aorta, the inferior vena cava, and the amniotic cavity. Experiments were performed at the fifth postoperative day recording fetal heart rate (FHR), arterial blood (FAP), and amniotic fluid (AFP) pressures, and aortic blood flow velocity (pulsed duplex Doppler) before, during, and after infusion of sodium nitroprusside (22.5-42 mu g min(-1)). Pulsatility index (PI) and resistance index (RI), corrected FAP as FAP - AFP, Doppler aortic blood flow rate (mi min(-1)), and peripheral resistance (cFAP/flow rate) were calculated. Results: During infusion of nitroprusside, cFAP reached a plateau significantly lower than control values (from 42.0 +/- 5.4 to 32.4 +/- 2.1; mean +/- SEM, five animals). Peripheral resistance decreased significantly from 0.073 +/- 0.013 to 0.057 +/- 0.01 mm Hg min ml(-1), and FHR increased from 141 +/- 10 beats per min (bpm) to 162 +/- 14 bpm (not significant), PI and RI increased significantly (from 1.24 +/- 0.1 to 1.49 +/- 0.2 and from 0.57 +/- 0.04 to 0.70 +/- 0.03, respectively), due to increased systolic maximal and decreased diastolic minimal velocities. Flow rates and mean velocities did not change. Control blood gas values stayed within normal ranges. When nitroprusside infusion was terminated, all values returned to control levels. Conclusions. In the ovine fetal abdominal aorta, resistance indicators RI and PI may increase when the peripheral vascular resistance actually decreases. It is suggested that nitroprusside might influence the vascular impedance, but that also the ratio of downstream (mainly umbilical-placental circulation) to upstream resistance might be increased.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ARTERIAL VELOCITY WAVEFORM; REGIONAL BLOOD FLOWS; SODIUM-NITROPRUSSIDE; CONTROLLED HYPOTENSION; RESISTANCE; PRESSURE; HEMODYNAMICS; FETUSES |
| Subjects: | 500 Science > 570 Life sciences 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Biology, Preclinical Medicine > Institut für Physiologie > Alumni or Retired > Prof. em. Dr. Waldemar Moll |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 22 Dec 2023 07:44 |
| Last Modified: | 22 Dec 2023 07:44 |
| URI: | https://pred.uni-regensburg.de/id/eprint/52188 |
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