Effect of body position and ventilation on umbilical artery and venous blood flows during delayed umbilical cord clamping in preterm lambs

Stuart B. Hooper, Kelly J Crossley, Valerie A. Zahra, Jeroen van Vonderen, Alison Moxham, Andrew W. Gill, Martin Kluckow, Arjan B te Pas, Euan M. Wallace, Graeme Polglase

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Objective While delayed umbilical cord clamping (UCC) is thought to facilitate placental to infant blood transfusion, the physiological factors regulating flow in the umbilical arteries and veins during delayed UCC is unknown. We investigated the effects of gravity, by changing fetal height relative to the placenta, and ventilation on umbilical blood flows and the cardiovascular transition during delayed UCC at birth. Methods Catheters and flow probes were implanted into preterm lambs (128 days) prior to delivery to measure pulmonary, carotid, umbilical artery (UaBF) and umbilical venous (UvBF) blood flows. Lambs were placed either 10 cm below or 10 cm above the ewe. Ventilation commenced 2-3 min before UCC and continued for 30 min after UCC. Results Gravity reduced umbilical and cerebral flows when lambs were placed below the midline, but the reduction in UaBF and UvBF was similar. Ventilation during delayed UCC reduced UvBF and UaBF by similar amounts, irrespective of the lamb's position, such that flows into and out of the placenta remained balanced. The effects of ventilation on umbilical flows were much greater than the effects of gravity, but no net placental to lamb blood transfusion could be detected under any condition. Cardiovascular parameters, cerebral oxygen kinetics and final blood volumes were similar in both groups 5 min after UCC. Conclusions Gravity caused small transient effects on umbilical and cerebral flow, but given changes were similar in umbilical arteries and veins, no net placental transfusion was detected. Ventilation during delayed UCC has a markedly greater influence on cardiovascular function in the newborn.

Original languageEnglish
Pages (from-to)F312-F319
Number of pages8
JournalArchives of Disease in Childhood: Fetal and Neonatal Edition
Volume102
Issue number4
DOIs
Publication statusPublished - 1 Jul 2017

Keywords

  • delayed umbilical cord clamping
  • Preterm Birth
  • Resuscitation
  • umbilical artery and umbilical venous blood flows
  • Umbilical Cord Clamping

Cite this

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title = "Effect of body position and ventilation on umbilical artery and venous blood flows during delayed umbilical cord clamping in preterm lambs",
abstract = "Objective While delayed umbilical cord clamping (UCC) is thought to facilitate placental to infant blood transfusion, the physiological factors regulating flow in the umbilical arteries and veins during delayed UCC is unknown. We investigated the effects of gravity, by changing fetal height relative to the placenta, and ventilation on umbilical blood flows and the cardiovascular transition during delayed UCC at birth. Methods Catheters and flow probes were implanted into preterm lambs (128 days) prior to delivery to measure pulmonary, carotid, umbilical artery (UaBF) and umbilical venous (UvBF) blood flows. Lambs were placed either 10 cm below or 10 cm above the ewe. Ventilation commenced 2-3 min before UCC and continued for 30 min after UCC. Results Gravity reduced umbilical and cerebral flows when lambs were placed below the midline, but the reduction in UaBF and UvBF was similar. Ventilation during delayed UCC reduced UvBF and UaBF by similar amounts, irrespective of the lamb's position, such that flows into and out of the placenta remained balanced. The effects of ventilation on umbilical flows were much greater than the effects of gravity, but no net placental to lamb blood transfusion could be detected under any condition. Cardiovascular parameters, cerebral oxygen kinetics and final blood volumes were similar in both groups 5 min after UCC. Conclusions Gravity caused small transient effects on umbilical and cerebral flow, but given changes were similar in umbilical arteries and veins, no net placental transfusion was detected. Ventilation during delayed UCC has a markedly greater influence on cardiovascular function in the newborn.",
keywords = "delayed umbilical cord clamping, Preterm Birth, Resuscitation, umbilical artery and umbilical venous blood flows, Umbilical Cord Clamping",
author = "Hooper, {Stuart B.} and Crossley, {Kelly J} and Zahra, {Valerie A.} and {van Vonderen}, Jeroen and Alison Moxham and Gill, {Andrew W.} and Martin Kluckow and {te Pas}, {Arjan B} and Wallace, {Euan M.} and Graeme Polglase",
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pages = "F312--F319",
journal = "Archives of Disease in Childhood: Fetal and Neonatal Edition",
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Effect of body position and ventilation on umbilical artery and venous blood flows during delayed umbilical cord clamping in preterm lambs. / Hooper, Stuart B.; Crossley, Kelly J; Zahra, Valerie A.; van Vonderen, Jeroen; Moxham, Alison; Gill, Andrew W.; Kluckow, Martin; te Pas, Arjan B; Wallace, Euan M.; Polglase, Graeme.

In: Archives of Disease in Childhood: Fetal and Neonatal Edition, Vol. 102, No. 4, 01.07.2017, p. F312-F319.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Effect of body position and ventilation on umbilical artery and venous blood flows during delayed umbilical cord clamping in preterm lambs

AU - Hooper, Stuart B.

AU - Crossley, Kelly J

AU - Zahra, Valerie A.

AU - van Vonderen, Jeroen

AU - Moxham, Alison

AU - Gill, Andrew W.

AU - Kluckow, Martin

AU - te Pas, Arjan B

AU - Wallace, Euan M.

AU - Polglase, Graeme

PY - 2017/7/1

Y1 - 2017/7/1

N2 - Objective While delayed umbilical cord clamping (UCC) is thought to facilitate placental to infant blood transfusion, the physiological factors regulating flow in the umbilical arteries and veins during delayed UCC is unknown. We investigated the effects of gravity, by changing fetal height relative to the placenta, and ventilation on umbilical blood flows and the cardiovascular transition during delayed UCC at birth. Methods Catheters and flow probes were implanted into preterm lambs (128 days) prior to delivery to measure pulmonary, carotid, umbilical artery (UaBF) and umbilical venous (UvBF) blood flows. Lambs were placed either 10 cm below or 10 cm above the ewe. Ventilation commenced 2-3 min before UCC and continued for 30 min after UCC. Results Gravity reduced umbilical and cerebral flows when lambs were placed below the midline, but the reduction in UaBF and UvBF was similar. Ventilation during delayed UCC reduced UvBF and UaBF by similar amounts, irrespective of the lamb's position, such that flows into and out of the placenta remained balanced. The effects of ventilation on umbilical flows were much greater than the effects of gravity, but no net placental to lamb blood transfusion could be detected under any condition. Cardiovascular parameters, cerebral oxygen kinetics and final blood volumes were similar in both groups 5 min after UCC. Conclusions Gravity caused small transient effects on umbilical and cerebral flow, but given changes were similar in umbilical arteries and veins, no net placental transfusion was detected. Ventilation during delayed UCC has a markedly greater influence on cardiovascular function in the newborn.

AB - Objective While delayed umbilical cord clamping (UCC) is thought to facilitate placental to infant blood transfusion, the physiological factors regulating flow in the umbilical arteries and veins during delayed UCC is unknown. We investigated the effects of gravity, by changing fetal height relative to the placenta, and ventilation on umbilical blood flows and the cardiovascular transition during delayed UCC at birth. Methods Catheters and flow probes were implanted into preterm lambs (128 days) prior to delivery to measure pulmonary, carotid, umbilical artery (UaBF) and umbilical venous (UvBF) blood flows. Lambs were placed either 10 cm below or 10 cm above the ewe. Ventilation commenced 2-3 min before UCC and continued for 30 min after UCC. Results Gravity reduced umbilical and cerebral flows when lambs were placed below the midline, but the reduction in UaBF and UvBF was similar. Ventilation during delayed UCC reduced UvBF and UaBF by similar amounts, irrespective of the lamb's position, such that flows into and out of the placenta remained balanced. The effects of ventilation on umbilical flows were much greater than the effects of gravity, but no net placental to lamb blood transfusion could be detected under any condition. Cardiovascular parameters, cerebral oxygen kinetics and final blood volumes were similar in both groups 5 min after UCC. Conclusions Gravity caused small transient effects on umbilical and cerebral flow, but given changes were similar in umbilical arteries and veins, no net placental transfusion was detected. Ventilation during delayed UCC has a markedly greater influence on cardiovascular function in the newborn.

KW - delayed umbilical cord clamping

KW - Preterm Birth

KW - Resuscitation

KW - umbilical artery and umbilical venous blood flows

KW - Umbilical Cord Clamping

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U2 - 10.1136/archdischild-2016-311159

DO - 10.1136/archdischild-2016-311159

M3 - Article

VL - 102

SP - F312-F319

JO - Archives of Disease in Childhood: Fetal and Neonatal Edition

JF - Archives of Disease in Childhood: Fetal and Neonatal Edition

SN - 1359-2998

IS - 4

ER -