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dc.contributor.authorLantto, Juulia
dc.contributor.authorErkinaro, Tiina
dc.contributor.authorHaapsamo, Mervi
dc.contributor.authorHuhta, Heikki
dc.contributor.authorAlanne, Leena
dc.contributor.authorKokki, Merja
dc.contributor.authorOhtonen, Pasi
dc.contributor.authorBhide, Amarnath
dc.contributor.authorAcharya, Ganesh
dc.contributor.authorRasanen, Juha
dc.date.accessioned2022-03-29T11:51:21Z
dc.date.available2022-03-29T11:51:21Z
dc.date.issued2021-11-09
dc.description.abstractA drop in arterial oxygen content activates fetal chemoreflex including an increase in sympathetic activity leading to peripheral vasoconstriction and redistribution of blood flow to protect the brain, myocardium, and adrenal glands. By using a chronically instrumented fetal sheep model with intact placental circulation at near-term gestation, we investigated the relationship between peripheral chemoreflex activation induced by hypoxemia and central hemodynamics. A total of 17 Åland landrace sheep fetuses at 115–128/145 gestational days were instrumented. Carotid artery was catheterized in 10 fetuses and descending aorta in 7 fetuses. After a 4-day recovery, baseline measurements of fetal arterial blood pressures, blood gas values, and fetal cardiovascular hemodynamics by pulsed Doppler ultrasonography were obtained under isoflurane anesthesia. Comparable data to baseline were collected 10 min (acute hypoxemia) and 60 min (prolonged hypoxemia) after maternal hypo-oxygenation to saturation level of 70%–80% was achieved. During prolonged hypoxemia, pH and base excess (BE) were lower and lactate levels were higher in the descending aorta than in the carotid artery. During hypoxemia mean arterial blood pressure (MAP) in the descending aorta increased, whereas in the carotid artery, MAP decreased. In addition, right pulmonary artery pulsatility index values increased, and the diastolic component in the aortic isthmus blood flow velocity waveform became more retrograde, thus decreasing the aortic isthmus antegrade/retrograde blood flow (AoI Net Flow) ratio. Both fetal ventricular cardiac outputs were maintained even during prolonged hypoxemia when significant fetal metabolic acidemia developed. Fetal chemoreflex activation induced by hypoxemia decreased the perfusion pressure in the cerebral circulation. Fetal weight-indexed left ventricular cardiac output (LVCO) or AoI Net Flow ratio did not correlate with a drop in carotid artery blood pressure.en_US
dc.identifier.citationLantto, Erkinaro, Haapsamo, Huhta, Alanne, Kokki, Ohtonen, Bhide, Acharya, Rasanen. Peripheral chemoreflex activation and cardiac function during hypoxemia in near-term fetal sheep without placental compromise. Journal of applied physiology. 2021;131(5):1486-1495en_US
dc.identifier.cristinIDFRIDAID 1998222
dc.identifier.doi10.1152/japplphysiol.01111.2020
dc.identifier.issn8750-7587
dc.identifier.issn1522-1601
dc.identifier.urihttps://hdl.handle.net/10037/24629
dc.language.isoengen_US
dc.publisherAmerican Physiological Societyen_US
dc.relation.journalJournal of applied physiology
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2021 The Author(s)en_US
dc.titlePeripheral chemoreflex activation and cardiac function during hypoxemia in near-term fetal sheep without placental compromiseen_US
dc.type.versionacceptedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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