Changes in renal function and blood volume in the newborn lamb delivered by cesarean section

ABSTRACT ABSTRACT: To determine the cause of the transient natriuresis in lambs within 1–2 h of birth, renal function and blood volume (BV) were measured in nine chronically catheter-ized

fetal sheep aged 139–145 d before and after delivery by cesarean section. After delivery, sodium excretion increased 8-fold. This was due to a transient rise in glomer-ular filtration rate

(by 39 o 21%, p < 0.02) and a fall in fractional reabsorption of sodium by the proximal tubule from 63.4 ± 2.5% to 53.4 ± 3.4% (p < 0.01). The distal tubule failed to compensate fully

for this fall, because fractional reabsorption by the distal tubule rose from 35.5 ± 2.4% to only 41.6 ± 2.2% (p < 0.05). The extent of the natriuresis did not depend on the lamb's

initial BV per kg at birth. However, the amount of fluid excreted and the clearance of sodium during a 45–min period within the first 1–1.25 h after birth were pproximately equal to the fall

in BV that occurred during this time. Thus, most of the fall in BV that occurs after delivery is due to renal salt and water losses. Because the natriuresis was greater if the lamb's

arterial pressure rose after birth, it is possible that a high arterial pressure in the immediate newborn period could result in salt and volume depletion. SIMILAR CONTENT BEING VIEWED BY

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RADIOFREQUENCY CATHETER-BASED RENAL DENERVATION Article Open access 20 July 2021 ARTICLE PDF AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * School of Physiology and Pharmacology, University

of New South Wales, Kensington, New South Wales, Australia Karen J Gibson & Eugenie R Lumbers Authors * Karen J Gibson View author publications You can also search for this author

inPubMed Google Scholar * Eugenie R Lumbers View author publications You can also search for this author inPubMed Google Scholar RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS

ARTICLE CITE THIS ARTICLE Gibson, K., Lumbers, E. Changes in Renal Function and Blood Volume in the Newborn Lamb Delivered by Cesarean Section. _Pediatr Res_ 36, 506–513 (1994).

https://doi.org/10.1203/00006450-199410000-00017 Download citation * Received: 20 April 1993 * Accepted: 10 May 1994 * Issue Date: 01 October 1994 * DOI:

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