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

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

doi:10.1136/archdischild-2015-309596

Cited by 6 publications

(5 citation statements)

References 29 publications

(26 reference statements)

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“…protective effect [10,24,25]. At present, our findings and those of others would justify recommendations to be vigilant for unexpected early decreases in HR following facemask placement.…”

Section: Statement Of Ethicssupporting

confidence: 53%

“…This is particularly relevant for the more stable infants with baseline HR >120 bpm, where commencement of respiratory support is less urgent. When respiratory support is provided, it is possible that more careful downward pressure on the facemask, use of humidified gases, concurrent stimulation, or alternative devices such as bi-nasal prongs may have a protective effect [10, 24, 25]. At present, our findings and those of others would justify recommendations to be vigilant for unexpected early decreases in HR following facemask placement.…”

Section: Discussionmentioning

confidence: 68%

“…HR is regarded as the most important marker of infant well-being after birth [1, 7, 8] and is a major determinant of cardiac output [9]. While a low HR can indicate hypoxia, other factors that modify HR include vagally mediated parasympathetic activation (including the TCR), sympathetic activation from peri-partum hypoxic-ischaemia, and alterations in cardiac preload [10]. Newborn resuscitation algorithms recommend maintaining HR >100–120 beats per minute (bpm) [1].…”

Section: Introductionmentioning

confidence: 99%

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Heart Rate Changes following Facemask Placement in Infants Born at ≥32+0 Weeks of Gestation

Badurdeen,

Brooijmans,

Blank

et al. 2023

Neonatology

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Introduction: Recent reports have raised concerns of cardiorespiratory deterioration in some infants receiving respiratory support at birth. We aimed to independently determine whether respiratory support with a facemask is associated with a decrease in heart rate (HR) in some late-preterm and term infants. Methods: Secondary analysis of data from infants born at ≥32+0 weeks of gestation at 2 perinatal centres in Melbourne, Australia. Change in HR up to 120 s after facemask placement, measured using 3-lead electrocardiography, was assessed every 3 s until 60 s and every 5 s thereafter from video recordings. Results: In the 15 s after facemask placement, 10/68 (15%) infants had a decrease in mean HR by >10 beats per minute (bpm) compared with their individual baseline mean HR in the 15 s before facemask placement. In 4 (6%) infants, HR decreased to <100 bpm. Nine out of 68 (13%) infants had an increase in mean HR by >10 bpm; 7 of these infants had a baseline HR <120 bpm. In univariable comparisons, the following characteristics were found not to be risk factors for a decrease in HR by >10 bpm: prematurity; type of respiratory support; hypoxaemia; early cord clamping; mode of birth; HR <120 bpm before mask placement. Six out of 63 infants (10%) who had HR ≥120 bpm after facemask placement had a late decrease in HR to <100 bpm between 30 and 120 s after facemask placement. Conclusion: Facemask respiratory support at birth is temporally associated with a decrease in HR in a subset of late-preterm and term infants.

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“…protective effect [10,24,25]. At present, our findings and those of others would justify recommendations to be vigilant for unexpected early decreases in HR following facemask placement.…”

Section: Statement Of Ethicssupporting

confidence: 53%

Section: Discussionmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Heart Rate Changes following Facemask Placement in Infants Born at ≥32+0 Weeks of Gestation

Badurdeen,

Brooijmans,

Blank

et al. 2023

Neonatology

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“…The lambs were anesthetized throughout the study, which prevents spontaneous breathing. While we know that gasping during asphyxia does not initiate the physiological transition at birth (Ong et al, 2016), the physiological response after ROSC in spontaneously breathing models is not yet known. The method of inducing asphyxia was different between the groups.…”

Section: Limitationsmentioning

confidence: 99%

Cardiopulmonary Resuscitation of Asystolic Newborn Lambs Prior to Umbilical Cord Clamping; the Timing of Cord Clamping Matters!

et al. 2020

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Background: Current guidelines recommend immediate umbilical cord clamping (UCC) for newborns requiring chest compressions (CCs). Physiological-based cord clamping (PBCC), defined as delaying UCC until after lung aeration, has advantages over immediate UCC in mildly asphyxiated newborns, but its efficacy in asystolic newborns requiring CC is unknown. The aim of this study was to compare the cardiovascular response to CCs given prior to or after UCC in asystolic near-term lambs. Methods: Umbilical, carotid, pulmonary, and femoral arterial flows and pressures as well as systemic and cerebral oxygenation were measured in near-term sheep fetuses [139 ± 2 (SD) days gestation]. Fetal asphyxia was induced until asystole ensued, whereupon lambs received ventilation and CC before (PBCC; n = 16) or after (n = 12) UCC. Epinephrine was administered 1 min after ventilation onset and in 3-min intervals thereafter. The PBCC group was further separated into UCC at either 1 min (PBCC 1 , n = 8) or 10 min (PBCC 10 , n = 8) after return of spontaneous circulation (ROSC). Lambs were maintained for a further 30 min after ROSC. Results: The duration of CCs received and number of epinephrine doses required to obtain ROSC were similar between groups. After ROSC, we found no physiological benefits if UCC was delayed for 1 min compared to immediate cord clamping (ICC). However, if UCC was delayed for 10 min after ROSC, we found significant reductions in post-asphyxial rebound hypertension, cerebral blood flow, and cerebral oxygenation. The prevention of the post-asphyxial rebound hypertension in the PBCC 10 group occurred due to the contribution of the placental circulation to a low peripheral resistance. As a result, left and right ventricular outputs continued to perfuse the placenta and were evidenced by reduced mean pulmonary blood flow, persistence of right-to-left shunting across the ductus arteriosus, and persistence of umbilical arterial and venous blood flows.

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“…While traditionally, HR has been seen as a pure marker of fetal and neonatal hypoxia, there is an increasing awareness that other factors, including cardiac preload, may play an important role [ 21 ]. When the umbilical cord is clamped, the infant is separated from the low-resistance placental circulation, systemic vascular resistance and blood pressure increase, and right-to-left ductal shunting decreases [ 22 ].…”

Section: Resultsmentioning

confidence: 99%

Significance of Neonatal Heart Rate in the Delivery Room—A Review

Nerdrum Aagaard,

Solevåg,

Saugstad

2023

Children

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Background: Heart rate (HR) is considered the main vital sign in newborns during perinatal transition, with a threshold of 100 beats per minute (bpm), below which, intervention is recommended. However, recent changes in delivery room management, including delayed cord clamping, are likely to have influenced normal HR transition. Objective: To summarize the updated knowledge about the factors, including measurement methods, that influence HR in newborn infants immediately after birth. Additionally, this paper provides an overview of delivery room HR as a prognostic indicator in different subgroups of newborns. Methods: We searched PubMed, EMBASE, and Google Scholar with the terms infant, heart rate, delivery room, resuscitation, pulse oximetry, and electrocardiogram. Results: Seven studies that described HR values in newborn infants immediately after birth were included. Pulse oximetry-derived HR percentiles after immediate cord clamping may not be applicable to the current practice of delayed cord clamping and the increasing use of delivery room electrocardiograms. Mask ventilation may adversely affect HR, particularly in premature and non-asphyxiated infants. Prolonged bradycardia is a negative prognostic factor, especially if combined with hypoxemia in infants <32 weeks of gestation. Conclusions: HR assessment in the delivery room remains important. However, the cardiopulmonary transition is affected by delayed cord clamping, gestational age, and underlying conditions.

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

Abstract: 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.

Cited by 6 publications

References 29 publications

Heart Rate Changes following Facemask Placement in Infants Born at ≥32+0 Weeks of Gestation

Heart Rate Changes following Facemask Placement in Infants Born at ≥32+0 Weeks of Gestation

Cardiopulmonary Resuscitation of Asystolic Newborn Lambs Prior to Umbilical Cord Clamping; the Timing of Cord Clamping Matters!

Significance of Neonatal Heart Rate in the Delivery Room—A Review

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