The cardiovascular response to birth asphyxia is altered by the surrounding environment

Tracey Ong, Kristina Sobotka, Melissa L. Siew, Kelly J. Crossley, Jeroen J van Vonderen, Graeme R. Polglase, Stuart B. Hooper

Research output: Contribution to journalArticleResearchpeer-review

1 Citation (Scopus)

Abstract

Background A sustained bradycardia is used as a major indicator of severe perinatal asphyxia. However, lambs asphyxiated ex utero do not exhibit the same bradycardic response as lambs asphyxiated in utero. It is possible that the local in utero environment may influence the initial cardiovascular response to asphyxia. We assessed the effect of facial immersion in water on the cardiovascular response to birth asphyxia. Methods Pregnant ewes (138±1 days gestation) were anaesthetised and fetuses were exteriorised and instrumented for measurement of cardiopulmonary haemodynamics. The lamb's head either remained in air (n=5) or was placed in water that was either warm (40±1°C; n=5) or at room temperature (21±1°C; n=5) before the umbilical cord was clamped to induce asphyxia. Results Heart rate after bradycardia onset was reduced in lambs asphyxiated with their head in cool water ('34±2%) and warm water ('25±4%) compared with those in air ('11±5%; p<0.05). Similarly, the decrease in blood pressure was faster in lambs with water around the face compared with those in air. From 75 s after asphyxia onset, mean and end-diastolic carotid blood flow was higher in the group asphyxiated in air (25±4 mL/kg/min), compared with the groups in water (13±3 mL/kg/min, warm water; 16±2 mL/kg/min, cool water; p<0.05). Conclusions The cardiovascular response to birth asphyxia is altered by the presence and temperature of water surrounding the head. The previous understanding of the vagally mediated bradycardia associated with birth asphyxia may include components of the diving reflex.

Original languageEnglish
Pages (from-to)F540-F545
JournalArchives of Disease in Childhood: Fetal and Neonatal Edition
Volume101
Issue number6
DOIs
Publication statusPublished - 1 Nov 2016

Keywords

  • Animal Research
  • Basic Science
  • Fetal Medicine
  • Neonatology
  • Resuscitation

Cite this

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title = "The cardiovascular response to birth asphyxia is altered by the surrounding environment",
abstract = "Background A sustained bradycardia is used as a major indicator of severe perinatal asphyxia. However, lambs asphyxiated ex utero do not exhibit the same bradycardic response as lambs asphyxiated in utero. It is possible that the local in utero environment may influence the initial cardiovascular response to asphyxia. We assessed the effect of facial immersion in water on the cardiovascular response to birth asphyxia. Methods Pregnant ewes (138±1 days gestation) were anaesthetised and fetuses were exteriorised and instrumented for measurement of cardiopulmonary haemodynamics. The lamb's head either remained in air (n=5) or was placed in water that was either warm (40±1°C; n=5) or at room temperature (21±1°C; n=5) before the umbilical cord was clamped to induce asphyxia. Results Heart rate after bradycardia onset was reduced in lambs asphyxiated with their head in cool water ('34±2{\%}) and warm water ('25±4{\%}) compared with those in air ('11±5{\%}; p<0.05). Similarly, the decrease in blood pressure was faster in lambs with water around the face compared with those in air. From 75 s after asphyxia onset, mean and end-diastolic carotid blood flow was higher in the group asphyxiated in air (25±4 mL/kg/min), compared with the groups in water (13±3 mL/kg/min, warm water; 16±2 mL/kg/min, cool water; p<0.05). Conclusions The cardiovascular response to birth asphyxia is altered by the presence and temperature of water surrounding the head. The previous understanding of the vagally mediated bradycardia associated with birth asphyxia may include components of the diving reflex.",
keywords = "Animal Research, Basic Science, Fetal Medicine, Neonatology, Resuscitation",
author = "Tracey Ong and Kristina Sobotka and Siew, {Melissa L.} and Crossley, {Kelly J.} and {van Vonderen}, {Jeroen J} and Polglase, {Graeme R.} and Hooper, {Stuart B.}",
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language = "English",
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The cardiovascular response to birth asphyxia is altered by the surrounding environment. / Ong, Tracey; Sobotka, Kristina; Siew, Melissa L.; Crossley, Kelly J.; van Vonderen, Jeroen J; Polglase, Graeme R.; Hooper, Stuart B.

In: Archives of Disease in Childhood: Fetal and Neonatal Edition, Vol. 101, No. 6, 01.11.2016, p. F540-F545.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - The cardiovascular response to birth asphyxia is altered by the surrounding environment

AU - Ong, Tracey

AU - Sobotka, Kristina

AU - Siew, Melissa L.

AU - Crossley, Kelly J.

AU - van Vonderen, Jeroen J

AU - Polglase, Graeme R.

AU - Hooper, Stuart B.

PY - 2016/11/1

Y1 - 2016/11/1

N2 - Background A sustained bradycardia is used as a major indicator of severe perinatal asphyxia. However, lambs asphyxiated ex utero do not exhibit the same bradycardic response as lambs asphyxiated in utero. It is possible that the local in utero environment may influence the initial cardiovascular response to asphyxia. We assessed the effect of facial immersion in water on the cardiovascular response to birth asphyxia. Methods Pregnant ewes (138±1 days gestation) were anaesthetised and fetuses were exteriorised and instrumented for measurement of cardiopulmonary haemodynamics. The lamb's head either remained in air (n=5) or was placed in water that was either warm (40±1°C; n=5) or at room temperature (21±1°C; n=5) before the umbilical cord was clamped to induce asphyxia. Results Heart rate after bradycardia onset was reduced in lambs asphyxiated with their head in cool water ('34±2%) and warm water ('25±4%) compared with those in air ('11±5%; p<0.05). Similarly, the decrease in blood pressure was faster in lambs with water around the face compared with those in air. From 75 s after asphyxia onset, mean and end-diastolic carotid blood flow was higher in the group asphyxiated in air (25±4 mL/kg/min), compared with the groups in water (13±3 mL/kg/min, warm water; 16±2 mL/kg/min, cool water; p<0.05). Conclusions The cardiovascular response to birth asphyxia is altered by the presence and temperature of water surrounding the head. The previous understanding of the vagally mediated bradycardia associated with birth asphyxia may include components of the diving reflex.

AB - Background A sustained bradycardia is used as a major indicator of severe perinatal asphyxia. However, lambs asphyxiated ex utero do not exhibit the same bradycardic response as lambs asphyxiated in utero. It is possible that the local in utero environment may influence the initial cardiovascular response to asphyxia. We assessed the effect of facial immersion in water on the cardiovascular response to birth asphyxia. Methods Pregnant ewes (138±1 days gestation) were anaesthetised and fetuses were exteriorised and instrumented for measurement of cardiopulmonary haemodynamics. The lamb's head either remained in air (n=5) or was placed in water that was either warm (40±1°C; n=5) or at room temperature (21±1°C; n=5) before the umbilical cord was clamped to induce asphyxia. Results Heart rate after bradycardia onset was reduced in lambs asphyxiated with their head in cool water ('34±2%) and warm water ('25±4%) compared with those in air ('11±5%; p<0.05). Similarly, the decrease in blood pressure was faster in lambs with water around the face compared with those in air. From 75 s after asphyxia onset, mean and end-diastolic carotid blood flow was higher in the group asphyxiated in air (25±4 mL/kg/min), compared with the groups in water (13±3 mL/kg/min, warm water; 16±2 mL/kg/min, cool water; p<0.05). Conclusions The cardiovascular response to birth asphyxia is altered by the presence and temperature of water surrounding the head. The previous understanding of the vagally mediated bradycardia associated with birth asphyxia may include components of the diving reflex.

KW - Animal Research

KW - Basic Science

KW - Fetal Medicine

KW - Neonatology

KW - Resuscitation

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U2 - 10.1136/archdischild-2015-309596

DO - 10.1136/archdischild-2015-309596

M3 - Article

VL - 101

SP - F540-F545

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

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

SN - 1359-2998

IS - 6

ER -