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Licensed Unlicensed Requires Authentication Published by De Gruyter March 18, 2010

Cardiac output and blood flow volume redistribution during acute maternal hypoxia in fetal sheep

  • Michael Tchirikov , Miriam Strohner and Alexander Scholz
From the journal


Objective: Acute hypoxia is one of the main causes of poor neonatal outcome. The aim of this study was the investigation of cardiac output (CO) and blood flow redistribution following induction of acute hypoxia in a fetal sheep model.

Method: We investigated 10 fetal sheep between 108 and 130 days of gestation. Acute hypoxia was induced by reducing the O2 saturation in the ventilated gas mixture of the maternal sheep to ∼75%. The CO, placental fraction of CO, Doppler parameters in the ductus venosus (DV), umbilical artery (UA) and vein (UV) were measured.

Results: The fetal pO2 decreased from 47.1 (7.19; 7.35) to 6.89 (6.78; 7.11) mm Hg [P=0.01, median, (95% CI)] during hypoxia. Fetal pH and BE were also significantly reduced. The DV/UV fraction increased from 15.3 (11.5; 19.8) to 51.1 (35.9; 62.1) (P=0.0001). The combined cardiac output [1228.1 (1024.3; 1686.4) vs. 987.8 (834, 1261) mL min–1], the placental fraction of the CO [31.5 (26; 42.1) vs. 26.9 (20.6; 29.3)%] and the right to left (R/L) heart ratio [1.76 (1.5; 2.2) vs. 1.3 (1.1; 1.6)] significantly decreased during hypoxia.

Conclusions: Acute hypoxia significantly increases the proportion of the placental blood passing through the DV and reduces the placental fraction of CO and the R/L heart ratio. These findings could be used as early signs of acute fetal hypoxia.

Corresponding author: Prof. Michael Tchirikov, MD, PhD Department of Obstetrics and Gynecology Johannes Gutenberg University Mainz University Medical Center Langenbeckstraße 1 55101 Mainz Germany Tel.: +49-(0) 6131-173291 Fax: +49-(0) 6131-173415

Received: 2009-6-7
Revised: 2009-12-11
Accepted: 2009-12-19
Published Online: 2010-03-18
Published Online: 2010-03-18
Published in Print: 2010-07-01

©2010 by Walter de Gruyter Berlin New York

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