title: Indirect relation between rises in oxygen consumption and left ventricular output at birth in lambs.
abstract: To examine the relation between increased newborn oxygen requirements and the postnatal rise in cardiac output, we measured left ventricular (LV) output, organ blood flows, and whole-body oxygen consumption using radioactive microspheres in late-gestation sheep fetuses and in the same animals 1 and 4 hours after cesarean section delivery. LV output rose from 264 +/- 23 ml.min-1.kg body wt-1 in fetuses to 444 +/- 33 ml.min-1.kg body wt-1 in lambs at 1 hour after delivery (p less than 0.005) and was unchanged at 4 hours after delivery. This rise in LV output was associated with a more than fourfold increase in the LV flow contribution to tissues situated distal to the ductus arteriosus (fetus, 51 +/- 9 ml.min-1.kg body wt-1; lamb, 226 +/- 22 ml.min-1.kg body wt-1; p less than 0.005), which were mainly perfused by the right ventricle in utero. However, average blood flow to body tissues was similar in fetuses (37 +/- 4 ml.min-1.100 g tissue-1), 1-hour lambs (39 +/- 4 ml.min-1.100 g tissue-1), and 4-hour lambs (40 +/- 5 ml.min-1.100 g tissue-1). Oxygen consumption increased by 58%, from 7.84 +/- 0.43 ml.min-1.kg body wt-1 in fetuses to 12.38 +/- 2.4 ml.min-1.kg body wt-1 in 1-hour lambs (p less than 0.01), and was unchanged in 4-hour lambs.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Centre for Early Human Development, Monash Medical Centre, Clayton, Australia.
authors.forename: J J
authors.initials: JJ
authors.lastname: Smolich
authors.forename: M
authors.initials: M
authors.lastname: Soust
authors.forename: P J
authors.initials: PJ
authors.lastname: Berger
authors.forename: A M
authors.initials: AM
authors.lastname: Walker
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001775:Blood Circulation; D002302:Cardiac Output; D003326:Coronary Circulation; D036861:Delivery, Obstetric; D005260:Female; D005318:Fetal Heart / Q000502:physiology*; D005865:Gestational Age; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D011247:Pregnancy; D012039:Regional Blood Flow; D012756:Sheep
chemical_list: D010100:Oxygen