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Endotracheal epinephrine at standard versus high dose for resuscitation of asystolic newborn lambs. Resuscitation 2024; 198:110191. [PMID: 38522732 DOI: 10.1016/j.resuscitation.2024.110191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/21/2024] [Accepted: 03/14/2024] [Indexed: 03/26/2024]
Abstract
INTRODUCTION Endotracheal (ET) epinephrine administration is an option during neonatal resuscitation, if the preferred intravenous (IV) route is unavailable. OBJECTIVES We assessed whether endotracheal epinephrine achieved return of spontaneous circulation (ROSC), and maintained physiological stability after ROSC, at standard and higher dose, in severely asphyxiated newborn lambs. METHODS Near-term fetal lambs were asphyxiated until asystole. Resuscitation was commenced with ventilation and chest compressions. Lambs were randomly allocated to: IV Saline placebo (5 ml/kg), IV Epinephrine (20 micrograms/kg), Standard-dose ET Epinephrine (100 micrograms/kg), and High-dose ET Epinephrine (1 mg/kg). After three allocated treatment doses, rescue IV Epinephrine was administered if ROSC had not occurred. Lambs achieving ROSC were monitored for 60 minutes. Brain histology was assessed for microbleeds. RESULTS ROSC in response to allocated treatment (without rescue IV Epinephrine) occurred in 1/6 Saline, 9/9 IV Epinephrine, 0/9 Standard-dose ET Epinephrine, and 7/9 High-dose ET Epinephrine lambs respectively. Blood pressure during CPR increased after treatment with IV Epinephrine and High-dose ET Epinephrine, but not Saline or Standard-dose ET Epinephrine. After ROSC, both ET Epinephrine groups had lower pH, higher lactate, and higher blood pressure than the IV Epinephrine group. Cortex microbleeds were more frequent in High-dose ET Epinephrine lambs (8/8 lambs examined, versus 3/8 in IV Epinephrine lambs). CONCLUSIONS The currently recommended dose of ET Epinephrine was ineffective in achieving ROSC. Without convincing clinical or preclinical evidence of efficacy, use of ET Epinephrine at this dose may not be appropriate. High-dose ET Epinephrine requires further evaluation before clinical translation.
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Targeted Neonatal Echocardiography in the Management of Neonatal Pulmonary Hypertension. Clin Perinatol 2024; 51:45-76. [PMID: 38325947 DOI: 10.1016/j.clp.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Pulmonary hypertension (PH) in neonates, originating from a range of disease states with heterogeneous underlying pathophysiology, is associated with significant morbidity and mortality. Although the final common pathway is a state of high right ventricular afterload leading to compromised cardiac output, multiple hemodynamic phenotypes exist in acute and chronic PH, for which cardiorespiratory treatment strategies differ. Comprehensive appraisal of pulmonary pressure, pulmonary vascular resistance, cardiac function, pulmonary and systemic blood flow, and extrapulmonary shunts facilitates delivery of individualized cardiovascular therapies in affected newborns.
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Assessing the influence of abdominal compression on time to return of circulation during resuscitation of asphyxiated newborn lambs: a randomised preclinical study. Arch Dis Child Fetal Neonatal Ed 2023:fetalneonatal-2023-326047. [PMID: 38123977 DOI: 10.1136/archdischild-2023-326047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023]
Abstract
OBJECTIVE During neonatal resuscitation, the return of spontaneous circulation (ROSC) can be achieved using epinephrine which optimises coronary perfusion by increasing diastolic pressure. Abdominal compression (AC) applied during resuscitation could potentially increase diastolic pressure and therefore help achieve ROSC. We assessed the use of AC during resuscitation of asystolic newborn lambs, with and without epinephrine. METHODS Near-term fetal lambs were instrumented for physiological monitoring and after delivery, asphyxiated until asystole. Resuscitation was commenced with ventilation followed by chest compressions. Lambs were randomly allocated to: intravenous epinephrine (20 µg/kg, n=9), intravenous epinephrine+continuous AC (n=8), intravenous saline placebo (5 mL/kg, n=6) and intravenous saline+AC (n=9). After three allocated treatment doses, rescue intravenous epinephrine was administered if ROSC had not occurred. Time to achieve ROSC was the primary outcome. Lambs achieving ROSC were ventilated and monitored for 60 min before euthanasia. Brain histology was assessed for micro-haemorrhage. RESULTS Use of AC did not influence mean time to achieve ROSC (epinephrine lambs 177 s vs epinephrine+AC lambs 179 s, saline lambs 602 s vs saline+AC lambs 585 s) or rate of ROSC (nine of nine lambs, eight of eight lambs, one of six lambs and two of eight lambs, respectively). Application of AC was associated with higher diastolic blood pressure (mean value >10 mm Hg), mean and systolic blood pressure and carotid blood flow during resuscitation. Cortex and deep grey matter micro-haemorrhage was more frequent in AC lambs. CONCLUSION Use of AC during resuscitation increased diastolic blood pressure, but did not impact time to ROSC.
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Lung aeration reduces blood pressure surges caused by umbilical cord milking in preterm lambs. Front Pediatr 2023; 11:1073904. [PMID: 37025294 PMCID: PMC10071016 DOI: 10.3389/fped.2023.1073904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 02/17/2023] [Indexed: 04/08/2023] Open
Abstract
Background Umbilical cord milking (UCM) at birth causes surges in arterial blood pressure and blood flow to the brain, which may explain the high risk of intraventricular haemorrhage (IVH) in extremely preterm infants receiving UCM. This high risk of IVH has not been reported in older infants. Objective We hypothesized that lung aeration before UCM, reduces the surge in blood pressure and blood flow induced by UCM. Methods At 126 days' gestation, fetal lambs (N = 8) were exteriorised, intubated and instrumented to measure umbilical, pulmonary, cerebral blood flows, and arterial pressures. Prior to ventilation onset, the umbilical cord was briefly (2-3 s) occluded (8 times), which was followed by 8 consecutive UCMs when all physiological parameters had returned to baseline. Lambs were then ventilated. After diastolic pulmonary blood flow markedly increased in response to ventilation, the lambs received a further 8 consecutive UCMs. Ovine umbilical cord is shorter than the human umbilical cord, with ∼10 cm available for UCMs. Therefore, 8 UCMs/occlusions were done to match the volume reported in the human studies. Umbilical cord clamping occurred after the final milk. Results Both umbilical cord occlusions and UCM caused significant increases in carotid arterial blood flow and pressure. However, the increases in systolic and mean arterial blood pressure (10 ± 3 mmHg vs. 3 ± 2 mmHg, p = 0.01 and 10 ± 4 mmHg vs. 6 ± 2 mmHg, p = 0.048, respectively) and carotid artery blood flow (17 ± 6 ml/min vs. 10 ± 6 ml/min, p = 0.02) were significantly greater when UCM occurred before ventilation onset compared with UCM after ventilation. Conclusions UCM after ventilation onset significantly reduces the increases in carotid blood flow and blood pressure caused by UCM.
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Point-of-care ultrasound (POCUS) protocol for systematic assessment of the crashing neonate-expert consensus statement of the international crashing neonate working group. Eur J Pediatr 2023; 182:53-66. [PMID: 36239816 PMCID: PMC9829616 DOI: 10.1007/s00431-022-04636-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/08/2022] [Accepted: 09/22/2022] [Indexed: 01/21/2023]
Abstract
Sudden unexpected clinical deterioration or cardiorespiratory instability is common in neonates and is often referred as a "crashing" neonate. The established resuscitation guidelines provide an excellent framework to stabilize and evaluate these infants, but it is primarily based upon clinical assessment only. However, clinical assessment in sick neonates is limited in identifying underlying pathophysiology. The Crashing Neonate Protocol (CNP), utilizing point-of-care ultrasound (POCUS), is specifically designed for use in neonatal emergencies. It can be applied both in term and pre-term neonates in the neonatal intensive care unit (NICU). The proposed protocol involves a stepwise systematic assessment with basic ultrasound views which can be easily learnt and reproduced with focused structured training on the use of portable ultrasonography (similar to the FAST and BLUE protocols in adult clinical practice). We conducted a literature review of the evidence-based use of POCUS in neonatal practice. We then applied stepwise voting process with a modified DELPHI strategy (electronic voting) utilizing an international expert group to prioritize recommendations. We also conducted an international survey among a group of neonatologists practicing POCUS. The lead expert authors identified a specific list of recommendations to be included in the proposed CNP. This protocol involves pre-defined steps focused on identifying the underlying etiology of clinical instability and assessing the response to intervention.Conclusion: To conclude, the newly proposed POCUS-based CNP should be used as an adjunct to the current recommendations for neonatal resuscitation and not replace them, especially in infants unresponsive to standard resuscitation steps, or where the underlying cause of deterioration remains unclear. What is known? • Point-of-care ultrasound (POCUS) is helpful in evaluation of the underlying pathophysiologic mechanisms in sick infants. What is new? • The Crashing Neonate Protocol (CNP) is proposed as an adjunct to the current recommendations for neonatal resuscitation, with pre-defined steps focused on gaining information regarding the underlying pathophysiology in unexplained "crashing" neonates. • The proposed CNP can help in targeting specific and early therapy based upon the underlying pathophysiology, and it allows assessment of the response to intervention(s) in a timely fashion.
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Single versus continuous sustained inflations during chest compressions and physiological-based cord clamping in asystolic lambs. Arch Dis Child Fetal Neonatal Ed 2022; 107:488-494. [PMID: 34844983 PMCID: PMC9411918 DOI: 10.1136/archdischild-2021-322881] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 11/03/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND The feasibility and benefits of continuous sustained inflations (SIs) during chest compressions (CCs) during delayed cord clamping (physiological-based cord clamping; PBCC) are not known. We aimed to determine whether continuous SIs during CCs would reduce the time to return of spontaneous circulation (ROSC) and improve post-asphyxial blood pressures and flows in asystolic newborn lambs. METHODS Fetal sheep were surgically instrumented immediately prior to delivery at ~139 days' gestation and asphyxia induced until lambs reached asystole. Lambs were randomised to either immediate cord clamping (ICC) or PBCC. Lambs then received a single SI (SIsing; 30 s at 30 cmH2O) followed by intermittent positive pressure ventilation, or continuous SIs (SIcont: 30 s duration with 1 s break). We thus examined 4 groups: ICC +SIsing, ICC +SIcont, PBCC +SIsing, and PBCC +SIcont. Chest compressions and epinephrine administration followed international guidelines. PBCC lambs underwent cord clamping 10 min after ROSC. Physiological and oxygenation variables were measured throughout. RESULTS The time taken to achieve ROSC was not different between groups (mean (SD) 4.3±2.9 min). Mean and diastolic blood pressure was higher during chest compressions in PBCC lambs compared with ICC lambs, but no effect of SIs was observed. SIcont significantly reduced pulmonary blood flow, diastolic blood pressure and oxygenation after ROSC compared with SIsing. CONCLUSION We found no significant benefit of SIcont over SIsing during CPR on the time to ROSC or on post-ROSC haemodynamics, but did demonstrate the feasibility of continuous SIs during advanced CPR on an intact umbilical cord. Longer-term studies are recommended before this technique is used routinely in clinical practice.
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Protocol for a Nested, Retrospective Study of the Australian Placental Transfusion Study Cohort. Cureus 2022; 14:e27693. [PMID: 36081962 PMCID: PMC9440991 DOI: 10.7759/cureus.27693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2022] [Indexed: 11/09/2022] Open
Abstract
Background Neonates, particularly if born preterm or with congenital anomalies, are among the pediatric patients most likely to need blood transfusion. However, they are also particularly vulnerable to adverse consequences of blood transfusion. Aiming to clamp the umbilical cord for at least a minute after birth is a simple safe procedure that is being increasingly adopted worldwide, although may be associated with increased rates of polycythemia and jaundice. It may also reduce the proportion of preterm babies who need a blood transfusion. The mechanisms for this are not fully understood. Potential mechanisms could include an increased volume of blood transfusion from the placenta to the baby after birth, and an overall reduction in the severity of illness in the first weeks after birth, which could lead to fewer blood tests and greater tolerance of anemia, or enhanced erythropoiesis. Objectives To investigate the mechanism behind the reduced need for blood transfusions after deferral of cord clamping. Methodology This protocol outlines the methods and data analysis plan for a study using nested retrospective data from a large randomized trial combined with additional data collected from patient medical and pathology records. The additional data items to be collected all relate to the receipt of transfusion and the factors that affect the risk for transfusion in preterm babies. The analysis will include all randomized babies from Australia and New Zealand for whom data are available. Causal mediation analysis is planned to estimate the effects of mediators on the relationship between the timing of cord clamping and the need for blood transfusion. The analysis is designed to discern whether initial severity of illness or the magnitude of placental transfusion mediates red blood cell transfusion dependence. Anticipated outcomes and dissemination We expect the study will identify potential strategies for reducing blood transfusions and associated negative outcomes in preterm infants. This will be relevant to researchers, clinicians, and parents. The results will be disseminated through publications, presentations, and inclusion in evidence-based guidelines.
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Comparison of intraosseous and intravenous epinephrine administration during resuscitation of asphyxiated newborn lambs. Arch Dis Child Fetal Neonatal Ed 2022; 107:311-316. [PMID: 34462318 DOI: 10.1136/archdischild-2021-322638] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/12/2021] [Indexed: 11/03/2022]
Abstract
OBJECTIVE Intraosseous access is recommended as a reasonable alternative for vascular access during newborn resuscitation if umbilical access is unavailable, but there are minimal reported data in newborns. We compared intraosseous with intravenous epinephrine administration during resuscitation of severely asphyxiated lambs at birth. METHODS Near-term lambs (139 days' gestation) were instrumented antenatally for measurement of carotid and pulmonary blood flow and systemic blood pressure. Intrapartum asphyxia was induced by umbilical cord clamping until asystole. Resuscitation commenced with positive pressure ventilation followed by chest compressions and the lambs received either intraosseous or central intravenous epinephrine (10 μg/kg); epinephrine administration was repeated every 3 min until return of spontaneous circulation (ROSC). The lambs were maintained for 30 min after ROSC. Plasma epinephrine levels were measured before cord clamping, at end asphyxia, and at 3 and 15 min post-ROSC. RESULTS ROSC was successful in 7 of 9 intraosseous epinephrine lambs and in 10 of 12 intravenous epinephrine lambs. The time and number of epinephrine doses required to achieve ROSC were similar between the groups, as were the achieved plasma epinephrine levels. Lambs in both groups displayed a similar marked overshoot in systemic blood pressure and carotid blood flow after ROSC. Blood gas parameters improved more quickly in the intraosseous lambs in the first 3 min, but were otherwise similar over the 30 min after ROSC. CONCLUSIONS Intraosseous epinephrine administration results in similar outcomes to intravenous epinephrine during resuscitation of asphyxiated newborn lambs. These findings support the inclusion of intraosseous access as a route for epinephrine administration in current guidelines.
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Effects of delayed versus immediate umbilical cord clamping in reducing death or major disability at 2 years corrected age among very preterm infants (APTS): a multicentre, randomised clinical trial. THE LANCET CHILD & ADOLESCENT HEALTH 2022; 6:150-157. [DOI: 10.1016/s2352-4642(21)00373-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 11/04/2021] [Accepted: 11/17/2021] [Indexed: 01/07/2023]
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Effect of maternal oxytocin on umbilical venous and arterial blood flows during physiological-based cord clamping in preterm lambs. PLoS One 2021; 16:e0253306. [PMID: 34138957 PMCID: PMC8211207 DOI: 10.1371/journal.pone.0253306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 06/03/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Delayed umbilical cord clamping (UCC) after birth is thought to cause placental to infant blood transfusion, but the mechanisms are unknown. It has been suggested that uterine contractions force blood out of the placenta and into the infant during delayed cord clamping. We have investigated the effect of uterine contractions, induced by maternal oxytocin administration, on umbilical artery (UA) and venous (UV) blood flows before and after ventilation onset to determine whether uterine contractions cause placental transfusion in preterm lambs. METHODS AND FINDINGS At ~128 days of gestation, UA and UV blood flows, pulmonary arterial blood flow (PBF) and carotid arterial (CA) pressures and blood flows were measured in three groups of fetal sheep during delayed UCC; maternal oxytocin following mifepristone, mifepristone alone, and saline controls. Each successive uterine contraction significantly (p<0.05) decreased UV (26.2±6.0 to 14.1±4.5 mL.min-1.kg-1) and UA (41.2±6.3 to 20.7 ± 4.0 mL.min-1.kg-1) flows and increased CA pressure and flow (47.1±3.4 to 52.8±3.5 mmHg and 29.4±2.6 to 37.3±3.4 mL.min-1.kg-1). These flows and pressures were partially restored between contractions, but did not return to pre-oxytocin administration levels. Ventilation onset during DCC increased the effects of uterine contractions on UA and UV flows, with retrograde UA flow (away from the placenta) commonly occurring during diastole. CONCLUSIONS We found no evidence that amplification of uterine contractions with oxytocin increase placental transfusion during DCC. Instead they decreased both UA and UV flow and caused a net loss of blood from the lamb. Uterine contractions did, however, have significant cardiovascular effects and reduced systemic and cerebral oxygenation.
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Patent ductus arteriosus management and the drift towards therapeutic nihilism - What is the evidence? Semin Fetal Neonatal Med 2021; 26:101219. [PMID: 33653600 DOI: 10.1016/j.siny.2021.101219] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The published literature on patent ductus arteriosus (PDA) management is challenging to interpret due to poorly designed trials with high rates of open label treatments, homogenisation of patients with varying physiological subtypes, poor treatment efficacy, and spontaneous closure in more mature infants. The perceived lack of clinical benefit has led to a drift away from medical and surgical treatment of all infants with a PDA. This therapeutic nihilism as a default response to PDA management fails to recognise the physiological relevance of a left-to-right shunt with early haemodynamic instability after birth and subsequent pulmonary volume overload with prolonged exposure. Clinicians need to know if therapeutic nihilism is safe. This review will provide an overview of the available data on the efficacy of known PDA treatments, conservative management and supportive care measures that are currently applied.
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A Randomized Placebo-Controlled Pilot Trial of Early Targeted Nonsteroidal Anti-Inflammatory Drugs in Preterm Infants with a Patent Ductus Arteriosus. J Pediatr 2021; 228:82-86.e2. [PMID: 32858033 DOI: 10.1016/j.jpeds.2020.08.062] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/28/2020] [Accepted: 08/21/2020] [Indexed: 12/19/2022]
Abstract
OBJECTIVE To establish the feasibility of a future large randomized trial to compare early treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) while awaiting spontaneous patent ductus arteriosus (PDA) closure. STUDY DESIGN Preterm infants at <29 weeks of gestation with a PDA diameter >1.5 mm and <72 hours after birth were randomized to NSAIDs vs placebo. No open-label NSAID treatment was allowed in either arm, but all infants with PDA volume load received supportive management, including optimization of airway pressure, careful fluid management, and diuretics as needed. The pilot outcomes were recruitment rate and incidence of open-label treatment. Secondary clinical outcomes included chronic lung disease or death, the planned primary outcome for a future large trial. RESULTS Overall, 54% of the approached parents consented to participate in the study. The median recruitment rate was 3 infants per month, and a total of 72 infants were randomized. One patient in each arm received open-label treatment. PDA closure rates were 74% for the NSAIDs arm vs 30% for the placebo arm, but this was not associated with significant changes in clinical outcomes. CONCLUSIONS This pilot trial showed that recruitment of more than one-half of eligible infants with a low incidence of open-label treatment is feasible. PDA closure rates and clinical outcomes were similar to those reported in previous PDA trials.
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Excess cerebral oxygen delivery follows return of spontaneous circulation in near-term asphyxiated lambs. Sci Rep 2020; 10:16443. [PMID: 33020561 PMCID: PMC7536421 DOI: 10.1038/s41598-020-73453-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/08/2020] [Indexed: 11/09/2022] Open
Abstract
Hypoxic-ischaemia renders the neonatal brain susceptible to early secondary injury from oxidative stress and impaired autoregulation. We aimed to describe cerebral oxygen kinetics and haemodynamics immediately following return of spontaneous circulation (ROSC) and evaluate non-invasive parameters to facilitate bedside monitoring. Near-term sheep fetuses [139 ± 2 (SD) days gestation, n = 16] were instrumented to measure carotid artery (CA) flow, pressure, right brachial arterial and jugular venous saturation (SaO2 and SvO2, respectively). Cerebral oxygenation (crSO2) was measured using near-infrared spectroscopy (NIRS). Following induction of severe asphyxia, lambs received cardiopulmonary resuscitation using 100% oxygen until ROSC, with oxygen subsequently weaned according to saturation nomograms as per current guidelines. We found that oxygen consumption did not rise following ROSC, but oxygen delivery was markedly elevated until 15 min after ROSC. CrSO2 and heart rate each correlated with oxygen delivery. SaO2 remained > 90% and was less useful for identifying trends in oxygen delivery. CrSO2 correlated inversely with cerebral fractional oxygen extraction. In conclusion, ROSC from perinatal asphyxia is characterised by excess oxygen delivery that is driven by rapid increases in cerebrovascular pressure, flow, and oxygen saturation, and may be monitored non-invasively. Further work to describe and limit injury mediated by oxygen toxicity following ROSC is warranted.
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Superior vena cava flow: Role, assessment and controversies in the management of perinatal perfusion. Semin Fetal Neonatal Med 2020; 25:101122. [PMID: 32467039 DOI: 10.1016/j.siny.2020.101122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The superior vena cava (SVC) is a large vein responsible for the venous return of blood from structures located superior to the diaphragm. The flow in the SVC can be assessed with Doppler ultrasound and can be used as a proxy for cerebral perfusion. Early clinical research studies showed that low SVC flow, particularly if for a prolonged period, was associated with short term morbidity such as intraventricular hemorrhage, mortality, and poorer neurodevelopmental outcomes. However, these findings have not been consistently reported in more recent studies, and the role of SVC flow in early management and as a predictor of poor long-term neurodevelopment has been questioned. This paper provides an overview of SVC assessment, the expected range of findings, and reviews the role of SVC flow as a diagnostic and monitoring tool for the assessment of perinatal perfusion.
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Cardiopulmonary Resuscitation of Asystolic Newborn Lambs Prior to Umbilical Cord Clamping; the Timing of Cord Clamping Matters! Front Physiol 2020; 11:902. [PMID: 32848852 PMCID: PMC7406709 DOI: 10.3389/fphys.2020.00902] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/06/2020] [Indexed: 12/14/2022] Open
Abstract
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 (PBCC1, n = 8) or 10 min (PBCC10, 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 PBCC10 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. Conclusion: It is possible to obtain ROSC after CC while the umbilical cord remains intact. There were no adverse effects of PBCC compared to ICC; however, the physiological changes observed after ROSC in the ICC and early PBCC groups may result in additional cerebral injury. Prolonging UCC after ROSC may provide significant physiological benefits that may reduce the risk of harm to the cerebral circulation.
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Systematic review and network meta-analysis with individual participant data on cord management at preterm birth (iCOMP): study protocol. BMJ Open 2020; 10:e034595. [PMID: 32229522 PMCID: PMC7170588 DOI: 10.1136/bmjopen-2019-034595] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
INTRODUCTION Timing of cord clamping and other cord management strategies may improve outcomes at preterm birth. However, it is unclear whether benefits apply to all preterm subgroups. Previous and current trials compare various policies, including time-based or physiology-based deferred cord clamping, and cord milking. Individual participant data (IPD) enable exploration of different strategies within subgroups. Network meta-analysis (NMA) enables comparison and ranking of all available interventions using a combination of direct and indirect comparisons. OBJECTIVES (1) To evaluate the effectiveness of cord management strategies for preterm infants on neonatal mortality and morbidity overall and for different participant characteristics using IPD meta-analysis. (2) To evaluate and rank the effect of different cord management strategies for preterm births on mortality and other key outcomes using NMA. METHODS AND ANALYSIS Systematic searches of Medline, Embase, clinical trial registries, and other sources for all ongoing and completed randomised controlled trials comparing cord management strategies at preterm birth (before 37 weeks' gestation) have been completed up to 13 February 2019, but will be updated regularly to include additional trials. IPD will be sought for all trials; aggregate summary data will be included where IPD are unavailable. First, deferred clamping and cord milking will be compared with immediate clamping in pairwise IPD meta-analyses. The primary outcome will be death prior to hospital discharge. Effect differences will be explored for prespecified participant subgroups. Second, all identified cord management strategies will be compared and ranked in an IPD NMA for the primary outcome and the key secondary outcomes. Treatment effect differences by participant characteristics will be identified. Inconsistency and heterogeneity will be explored. ETHICS AND DISSEMINATION Ethics approval for this project has been granted by the University of Sydney Human Research Ethics Committee (2018/886). Results will be relevant to clinicians, guideline developers and policy-makers, and will be disseminated via publications, presentations and media releases. REGISTRATION NUMBER Australian New Zealand Clinical Trials Registry (ANZCTR) (ACTRN12619001305112) and International Prospective Register of Systematic Reviews (PROSPERO, CRD42019136640).
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Effect of spontaneous breathing on umbilical venous blood flow and placental transfusion during delayed cord clamping in preterm lambs. Arch Dis Child Fetal Neonatal Ed 2020; 105:26-32. [PMID: 31092674 PMCID: PMC6961560 DOI: 10.1136/archdischild-2018-316044] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 03/04/2019] [Accepted: 04/02/2019] [Indexed: 11/03/2022]
Abstract
INTRODUCTION During delayed umbilical cord clamping, the factors underpinning placental transfusion remain unknown. We hypothesised that reductions in thoracic pressure during inspiration would enhance placental transfusion in spontaneously breathing preterm lambs. OBJECTIVE Investigate the effect of spontaneous breathing on umbilical venous flow and body weight in preterm lambs. METHODS Pregnant sheep were instrumented at 132-133 days gestational age to measure fetal common umbilical venous, pulmonary and cerebral blood flows as well as arterial and intrapleural (IP) pressures. At delivery, doxapram and caffeine were administered to promote breathing. Lamb body weights were measured continuously and breathing was assessed by IP pressure changes. RESULTS In 6 lambs, 491 out of 1117 breaths were analysed for change in body weight. Weight increased in 46.6% and decreased in 47.5% of breaths. An overall mean increase of 0.02±2.5 g per breath was calculated, and no net placental transfusion was observed prior to cord clamping (median difference in body weight 52.3 [-54.9-166.1] g, p=0.418). Umbilical venous (UV) flow transiently decreased with each inspiration, and in some cases ceased, before UV flow normalised during expiration. The reduction in UV flow was positively correlated with the standardised reduction in (IP) pressure, increasing by 109 mL/min for every SD reduction in IP pressure. Thus, the reduction in UV flow was closely related to inspiratory depth. CONCLUSIONS Spontaneous breathing had no net effect on body weight in preterm lambs at birth. UV blood flow decreased as inspiratory effort increased, possibly due to constriction of the inferior vena cava caused by diaphragmatic contraction, as previously observed in human fetuses.
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Evolution of Training Guidelines for Echocardiography Performed by the Neonatologist: Toward Hemodynamic Consultation. J Am Soc Echocardiogr 2019; 32:785-790. [PMID: 30926403 DOI: 10.1016/j.echo.2019.02.0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Indexed: 05/28/2023]
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Evolution of Training Guidelines for Echocardiography Performed by the Neonatologist: Toward Hemodynamic Consultation. J Am Soc Echocardiogr 2019; 32:785-790. [PMID: 30926403 DOI: 10.1016/j.echo.2019.02.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Indexed: 11/24/2022]
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The Effect of Antenatal Betamethasone on White Matter Inflammation and Injury in Fetal Sheep and Ventilated Preterm Lambs. Dev Neurosci 2019; 40:497-507. [PMID: 30840951 DOI: 10.1159/000496466] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 12/20/2018] [Indexed: 11/19/2022] Open
Abstract
Antenatal administration of betamethasone (BM) is a common antecedent of preterm birth, but there is limited information about its impact on the acute evolution of preterm neonatal brain injury. We aimed to compare the effects of maternal BM in combination with mechanical ventilation on the white matter (WM) of late preterm sheep. At 0.85 of gestation, pregnant ewes were randomly assigned to receive intra-muscular (i.m.) saline (n = 9) or i.m. BM (n = 13). Lambs were delivered and unventilated controls (UVCSal, n = 4; UVCBM, n = 6) were humanely killed without intervention; ventilated lambs (VentSal, n = 5; VentBM, n = 7) were injuriously ventilated for 15 min, followed by conventional ventilation for 75 min. Cardiovascular and cerebral haemodynamics and oxygenation were measured continuously. The cerebral WM underwent assessment of inflammation and injury, and oxidative stress was measured in the cerebrospinal fluid (CSF). In the periventricular and subcortical WM tracts, the proportion of amoeboid (activated) microglia, the density of astrocytes, and the number of blood vessels with protein extravasation were higher in UVCBM than in UVCSal (p < 0.05 for all). During ventilation, tidal volume, mean arterial pressure, carotid blood flow, and oxygen delivery were higher in -VentBM lambs (p < 0.05 vs. VentSal). In the subcortical WM, microglial infiltration was increased in the VentSal group compared to UVCSal. The proportion of activated microglia and protein extravasation was higher in the VentBM group compared to VentSal within the periventricular and subcortical WM tracts (p < 0.05). CSF oxidative stress was increased in the VentBM group compared to UVCSal, UVCBM, and VentSal groups (p < 0.05). Antenatal BM was associated with inflammation and vascular permeability in the WM of late preterm fetal sheep. During the immediate neonatal period, the increased carotid perfusion and oxygen delivery in BM-treated lambs was associated with increased oxidative stress, microglial activation and microvascular injury.
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Does the use of an iodine-containing contrast agent to visualise the PICC tip in preterm babies cause hypothyroidism? A randomised controlled trial. Arch Dis Child Fetal Neonatal Ed 2019; 104:F212-F214. [PMID: 29807945 DOI: 10.1136/archdischild-2017-314665] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/25/2018] [Accepted: 05/14/2018] [Indexed: 11/04/2022]
Abstract
AIM To compare thyroid function tests in preterm neonates (<30 weeks and >48 hour old) exposed to iodine-based contrast with controls and ascertain the certainty of peripherally inserted central catheter (PICC) tip position. METHODS Infants requiring a PICC were randomised to receive 0.3 mL of iodine-containing contrast or normal saline. The primary outcome was the difference in thyroid-stimulating hormone (TSH) levels on day 14 post PICC insertion and on day 28 of life. RESULTS 41 infants were randomised with no significant differences in TSH level (mIU/L) at day 14 post PICC insertion (3.1 vs 2) or on day 28 of life (2.2 vs 1.7). The PICC tip was more easily localised in the contrast group (85% vs 55%). Urinary iodine levels were significantly increased in the contrast-exposed group. CONCLUSION Use of contrast did not suppress subsequent thyroid function and helped visualise the PICC tip with more certainty. CLINICAL TRIAL REGISTRATION NUMBER ACTRN12614000560695, pre-result.
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Transfusion or Timing: The Role of Blood Volume in Delayed Cord Clamping During the Cardiovascular Transition at Birth. Front Pediatr 2019; 7:405. [PMID: 31649907 PMCID: PMC6794342 DOI: 10.3389/fped.2019.00405] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 09/19/2019] [Indexed: 01/08/2023] Open
Abstract
Placental transfusion has been thought to be the main benefit of delayed umbilical cord clamping (DCC) in preterm neonates. However, the importance of cardiovascular stability provided by allowing lung aeration prior to cord clamping has recently been highlighted. We aimed to determine the influence of blood volume changes on cardiovascular stability at birth. Preterm lambs (0.85 gestation) were instrumented for measurement of pulmonary, systemic and cerebral blood pressures and flows, systemic oxygen saturation and cerebral oxygenation. Left ventricular output (LVO) was assessed by Doppler Echocardiography. Lambs underwent immediate cord clamping followed by (1) 25 ml/kg infusion of whole blood over (90 s; or 2) withdrawal of 10 ml/kg blood over 90 s. Ventilation was initiated 30 s after volume change (2 min after cord clamping) and was maintained for 30 min. Blood infusion significantly increased pulmonary blood flow (PBF) which maintained systemic cardiac output during the infusion, and increased carotid arterial pressure, flow and heart rate, which remained elevated until after ventilation onset. Upon completion of transfusion PBF rapidly returned to control levels and LVO decreased. Conversely, blood withdrawal decreased PBF and LVO. The cardiovascular changes that accompanied ventilation onset were similar between groups. Providing a blood volume transfusion immediately after umbilical cord clamping maintains PBF and cardiac output during the transfusion, which does not persist beyond the period of the transfusion. Our study implies that an apneic newborn cannot maintain cardiac output through an increase blood volume alone. Importantly, delaying umbilical cord clamping until after breathing/aeration of the lung may be a way to maintain cardiac output throughout delivery at birth.
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Haemodynamic effects of umbilical cord milking in premature sheep during the neonatal transition. Arch Dis Child Fetal Neonatal Ed 2018; 103:F539-F546. [PMID: 29208663 PMCID: PMC6278653 DOI: 10.1136/archdischild-2017-314005] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/31/2017] [Accepted: 11/05/2017] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Umbilical cord milking (UCM) at birth may benefit preterm infants, but the physiological effects of UCM are unknown. We compared the physiological effects of two UCM strategies with immediate umbilical cord clamping (UCC) and physiological-based cord clamping (PBCC) in preterm lambs. METHODS At 126 days' gestational age, fetal lambs were exteriorised, intubated and instrumented to measure umbilical, pulmonary and cerebral blood flows and arterial pressures. Lambs received either (1) UCM without placental refill (UCMwoPR); (2) UCM with placental refill (UCMwPR); (3) PBCC, whereby ventilation commenced prior to UCC; or (4) immediate UCC. UCM involved eight milks along a 10 cm length of cord, followed by UCC. RESULTS A net volume of blood was transferred into the lamb during UCMwPR (8.8 mL/kg, IQR 8-10, P=0.01) but not during UCMwoPR (0 mL/kg, IQR -2.8 to 1.7) or PBCC (1.1 mL/kg, IQR -1.3 to 4.3). UCM had no effect on pulmonary blood flow, but caused large fluctuations in mean carotid artery pressures (MBP) and blood flows (CABF). In UCMwoPR and UCMwPR lambs, MBP increased by 12%±1% and 8%±1% and CABF increased by 32%±2% and 15%±2%, respectively, with each milk. Cerebral oxygenation decreased the least in PBCC lambs (17%, IQR 13-26) compared with UCMwoPR (26%, IQR 23-25, P=0.03), UCMwPR (35%, IQR 27-44, P=0.02) and immediate UCC (34%, IQR 28-41, P=0.02) lambs. CONCLUSIONS UCMwoPR failed to provide placental transfusion, and UCM strategies caused considerable haemodynamic disturbance. UCM does not provide the same physiological benefits of PBCC. Further review of UCM is warranted before adoption into routine clinical practice.
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Physiologically based cord clamping stabilises cardiac output and reduces cerebrovascular injury in asphyxiated near-term lambs. Arch Dis Child Fetal Neonatal Ed 2018; 103:F530-F538. [PMID: 29191812 DOI: 10.1136/archdischild-2017-313657] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 10/23/2017] [Accepted: 11/05/2017] [Indexed: 11/03/2022]
Abstract
BACKGROUND Physiologically based cord clamping (PBCC) has advantages over immediate cord clamping (ICC) during preterm delivery, but its efficacy in asphyxiated infants is not known. We investigated the physiology of PBCC following perinatal asphyxia in near-term lambs. METHODS Near-term sheep fetuses (139±2 (SD) days' gestation) were instrumented to measure umbilical, carotid, pulmonary and femoral arterial flows and pressures. Systemic and cerebral oxygenation was recorded using pulse oximetry and near-infrared spectroscopy, respectively. Fetal asphyxia was induced until mean blood pressure reached ~20 mm Hg, where lambs underwent ICC and initiation of ventilation (n=7), or ventilation for 15 min prior to umbilical cord clamping (PBCC; n=8). Cardiovascular parameters were measured and white and grey matter microvascular integrity assessed using qRT-PCR and immunohistochemistry. RESULTS PBCC restored oxygenation and cardiac output at the same rate and in a similar fashion to lambs resuscitated following ICC. However, ICC lambs had a rapid and marked overshoot in mean systemic arterial blood pressure from 1 to 10 min after ventilation onset, which was largely absent in PBCC lambs. ICC lambs had increased cerebrovascular injury, as indicated by reduced expression of blood-brain barrier proteins and increased cerebrovascular protein leakage in the subcortical white matter (by 86%) and grey matter (by 47%). CONCLUSION PBCC restored cardiac output and oxygenation in an identical time frame as ICC, but greatly mitigated the postasphyxia rebound hypertension measured in ICC lambs. This likely protected the asphyxiated brain from cerebrovascular injury. PBCC may be a more suitable option for the resuscitation of the asphyxiated newborn compared with the current standard of ICC.
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Role of neonatologist-performed echocardiography in the assessment and management of patent ductus arteriosus physiology in the newborn. Semin Fetal Neonatal Med 2018; 23:292-297. [PMID: 29551482 DOI: 10.1016/j.siny.2018.03.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Neonatologist-performed echocardiography (NPE) is an indispensable tool in the haemodynamic management of critically ill newborn infants. NPE is used to facilitate timely diagnosis of a patent ductus arteriosus (PDA) in preterm infants and to assess its haemodynamic significance. Before treatment is considered, it is obligatory to confirm structural cardiac normality. Importantly, NPE offers the ability to guide therapeutic interventions, allowing an individualised haemodynamic management approach to the PDA. After discussing PDA pathophysiology, an overview is provided on the role of NPE in the assessment and management of PDA in preterm infants.
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Abstract
Assessment and management of a patent ductus arteriosus (PDA) in premature infants remains problematic. The more immature the infant, the more likely a PDA is to be present, due to lower spontaneous PDA closure rates. Clinicians now recognize that not all PDAs require treatment and that selection of the group of infants with a more hemodynamically relevant PDA, often manifesting as an increasing systemic-to-pulmonary shunt, is increasingly important. Ultrasound is the mainstay of diagnosis and physiological assessment of the PDA; however, there are other methodologies used to assess hemodynamic importance of the PDA. These range from assessment of clinical signs through biomarkers and finally to physiological assessment of the end-organ effect of the PDA, using methods such as cerebral Doppler or near infra-red spectroscopy. Extended assessment of a PDA's physiological effect may lead to a more individualized approach to PDA treatment.
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Interobserver agreement and image quality of functional cardiac ultrasound measures used in a randomised trial of delayed cord clamping in preterm infants. Arch Dis Child Fetal Neonatal Ed 2018; 103:F257-F263. [PMID: 28818853 DOI: 10.1136/archdischild-2016-312006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 06/26/2017] [Accepted: 06/29/2017] [Indexed: 11/04/2022]
Abstract
OBJECTIVE Functional cardiac ultrasound measures are used clinically and in trials for assessing the haemodynamic status of newborn infants. Superior vena cava (SVC) flow and right ventricular output (RVO) are established measures of systemic blood flow on the first postnatal day. The objective was to assess image quality and interobserver agreement of these measures in preterm infants enrolled in a randomised trial of immediate versus delayed cord clamping. DESIGN AND SETTING Image quality and interobserver agreement for SVC flow, RVO and ductus arteriosus (DA) size were assessed on measurements taken at 3-6, 6-12 and 20-28 hours for the first 10 infants enrolled at each of four sites (total 40). Bland-Altman plots were constructed; mean difference (bias) and limits of agreement (LOA) were calculated. Potential sources of variation were explored. RESULTS Quality was judged satisfactory for >97% of images. The mean difference and LOA between the observers were 5.4 mL/kg/min and -49.0 to 59.8 mL/kg/min for SVC flow, -26.6 mL/kg/min and -131.4 to 78.2 mL/kg/min for RVO, and 0 mm and -0.8 to 0.8 mm for DA diameter, respectively. The principal source of measurement error for SVC flow was diameter, and for RVO, diameter and velocity time integral. The difference between observers for both SVC and RVO was significantly associated with site. CONCLUSION Interobserver variability for SVC flow is consistent with that previously reported, but higher for RVO. The findings should be incorporated into clinical practice, training, accreditation and trial design.
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Barriers to the Implementation of Newborn Pulse Oximetry Screening: A Different Perspective. Int J Neonatal Screen 2018; 4:4. [PMID: 33072930 PMCID: PMC7548906 DOI: 10.3390/ijns4010004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/08/2018] [Indexed: 11/16/2022] Open
Abstract
Pulse oximetry screening of the well newborn to assist in the diagnosis of critical congenital heart disease (CCHD) is increasingly being adopted. There are advantages to diagnosing CCHD prior to collapse, particularly if this occurs outside of the hospital setting. The current recommended approach links pulse oximetry screening with the assessment for CCHD. An alternative approach is to document the oxygen saturation as part of a routine set of vital signs in each newborn infant prior to discharge, delinking the measurement of oxygen saturation from assessment for CCHD. This approach, the way that many hospitals which contribute to the Australian New Zealand Neonatal Network (ANZNN) have introduced screening, has the potential benefits of decreasing parental anxiety and expectation, not requiring specific consent, changing the interpretation of false positives and therefore the timing of the test, and removing the pressure to perform an immediate echocardiogram if the test is positive. There are advantages of introducing a formal screening program, including the attainment of adequate funding and a universal approach, but the barriers noted above need to be dealt with and the process of acceptance by a national body as a screening test can take many years.
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Abstract
Assessment and treatment of the VLBW infant with cardiovascular impairment requires understanding of the underlying physiology of the infant in transition. The situation is dynamic with changes occurring in systemic blood pressure, pulmonary pressures, myocardial function, and ductal shunt in the first postnatal days. New insights into the role of umbilical cord clamping in the transitional circulation have been provided by large clinical trials of early versus later cord clamping and a series of basic science reports describing the physiology in an animal model. Ultrasound assessment is invaluable in assessment of the physiology of the transition and can provide information about the size and shunt direction of the ductus arteriosus, the function of the myocardium and its filling as well as measurements of the cardiac output and an estimate of the state of peripheral vascular resistance. This information not only allows more specific treatment but it will often reduce the need for treatment.
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Ventilation Prior to Umbilical Cord Clamping Improves Cardiovascular Stability and Oxygenation in Preterm Lambs After Exposure to Intrauterine Inflammation. Front Pediatr 2018; 6:286. [PMID: 30410874 PMCID: PMC6209675 DOI: 10.3389/fped.2018.00286] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 09/17/2018] [Indexed: 11/30/2022] Open
Abstract
Background: Delaying umbilical cord clamping until after aeration of the lung (physiological-based cord clamping; PBCC) maintains cardiac output and oxygenation in preterm lambs at birth, however, its efficacy after intrauterine inflammation is not known. Given the high incidence of chorioamnionitis in preterm infants, we investigated whether PBCC conferred any benefits compared to immediate cord clamping (ICC) in preterm lambs exposed antenatally to 7 days of intrauterine inflammation. Methods: Ultrasound guided intraamniotic injection of 20 mg Lipopolysaccharide (from E. coli:055:B5) was administered to pregnant ewes at 0.8 gestation. Seven days later, ewes were anesthetized, preterm fetuses exteriorised via cesarean section, and instrumented for continuous measurement of pulmonary, systemic and cerebral pressures and flows, and systemic, and cerebral oxygenation. Lambs were then randomized to either PBCC, whereupon ventilation was initiated and maintained for 3 min prior to umbilical cord clamping, or ICC where the umbilical cord was cut and ventilation initiated 30 s later. Ventilation was maintained for 30 min. Results: ICC caused a rapid fall in systemic (by 25%) and cerebral (by 11%) oxygen saturation in ICC lambs, concurrent with a rapid increase in carotid arterial pressure and heart rate. The overshoot in carotid arterial pressure was sustained in ICC lambs for the first 20 min of the study. PBCC maintained cardiac output and prevented the fall in cerebral oxygen delivery at birth. PBCC lambs had lower respiratory compliance and higher respiratory requirements throughout the study. Conclusion: PBCC mitigated the adverse effects of ICC on oxygenation and cardiac output, and therefore could be more beneficial in preterm babies exposed to antenatal inflammation as it maintains cardiac output and oxygen delivery. The increased respiratory requirements require further investigation in this sub-group of preterm infants.
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Abstract
BACKGROUND The preferred timing of umbilical-cord clamping in preterm infants is unclear. METHODS We randomly assigned fetuses from women who were expected to deliver before 30 weeks of gestation to either immediate clamping of the umbilical cord (≤10 seconds after delivery) or delayed clamping (≥60 seconds after delivery). The primary composite outcome was death or major morbidity (defined as severe brain injury on postnatal ultrasonography, severe retinopathy of prematurity, necrotizing enterocolitis, or late-onset sepsis) by 36 weeks of postmenstrual age. Analyses were performed on an intention-to-treat basis, accounting for multiple births. RESULTS Of 1634 fetuses that underwent randomization, 1566 were born alive before 30 weeks of gestation; of these, 782 were assigned to immediate cord clamping and 784 to delayed cord clamping. The median time between delivery and cord clamping was 5 seconds and 60 seconds in the respective groups. Complete data on the primary outcome were available for 1497 infants (95.6%). There was no significant difference in the incidence of the primary outcome between infants assigned to delayed clamping (37.0%) and those assigned to immediate clamping (37.2%) (relative risk, 1.00; 95% confidence interval, 0.88 to 1.13; P=0.96). The mortality was 6.4% in the delayed-clamping group and 9.0% in the immediate-clamping group (P=0.03 in unadjusted analyses; P=0.39 after post hoc adjustment for multiple secondary outcomes). There were no significant differences between the two groups in the incidences of chronic lung disease or other major morbidities. CONCLUSIONS Among preterm infants, delayed cord clamping did not result in a lower incidence of the combined outcome of death or major morbidity at 36 weeks of gestation than immediate cord clamping. (Funded by the Australian National Health and Medical Research Council [NHMRC] and the NHMRC Clinical Trials Centre; APTS Australian and New Zealand Clinical Trials Registry number, ACTRN12610000633088 .).
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Feasibility and utility of portable ultrasound during retrieval of sick preterm infants. Acta Paediatr 2017; 106:1296-1301. [PMID: 28419552 DOI: 10.1111/apa.13881] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/24/2017] [Accepted: 04/11/2017] [Indexed: 11/29/2022]
Abstract
AIM Document the incidence of haemodynamic pathology in critically ill preterm newborns requiring transport. METHOD A transport neonatologist performed cardiac and cerebral ultrasound before and after transportation of infants born ≤30 weeks gestation. RESULTS Forty-four newborns were studied in 2008-2015; of them, 21 were transported by road, 19, by helicopter and four, by fixed wing: median birthweight, 1130 g (680-1960 g) and median gestation, 27 weeks (23-30); 30 of 44 were male babies. Antenatal steroid course was complete in two babies. Ultrasound in the referring hospital was at a mean of two hours: 47 minutes (00:15-7:00) of age. Low systemic blood flow was common: 50% had right ventricular output <150mL/kg/min and 23%, a superior vena cava flow <50mL/kg/min. at stabilisation. Cranial US: 10 Grade I IVH, 2 Grade II IVH, 1 Grade IV IVH and 32 normal scans pretransport. After transport, three further Grade I IVH were reported. Mortality was higher in the babies with low systemic blood flow: 4 of 12 (33%) died vs 1 of 31 (6%) in the normal flow group (OR = 7.2, 95% CI: 1.1 to 47, p = 0.022). CONCLUSION Point-of-care ultrasound during the retrieval of preterm infants confirms a high incidence of haemodynamic pathology. The use of ultrasound during transport may provide an opportunity for earlier targeted circulatory support.
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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. Arch Dis Child Fetal Neonatal Ed 2017; 102:F312-F319. [PMID: 27827796 PMCID: PMC5537513 DOI: 10.1136/archdischild-2016-311159] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 10/13/2016] [Indexed: 12/21/2022]
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.
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Measurement of neonatal heart rate using handheld Doppler ultrasound. Arch Dis Child Fetal Neonatal Ed 2017; 102:F116-F119. [PMID: 27288393 DOI: 10.1136/archdischild-2016-310669] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 05/18/2016] [Accepted: 05/23/2016] [Indexed: 12/18/2022]
Abstract
OBJECTIVE This pilot study aimed to determine whether handheld Doppler ultrasound is feasible and reliable for measuring neonatal heart rate (HR) when compared with ECG. SETTING Stable newborns were recruited from the neonatal intensive care unit and postnatal ward between July 2014 and January 2015 at Royal North Shore Hospital, Sydney, Australia. INTERVENTIONS Each newborn had their HR recorded every 15 s over 145 s using four different modalities: ECG, counted audible Doppler (AD) over 10 s, pulse oximetry (PO) and the Doppler display (DD). OUTCOME MEASURES The correlation and variation between each modality and ECG. RESULTS 51 newborns with a median gestational age of 38 weeks (27-41) and a mean weight of 2.78 kg (0.82 to 4.76) with a median postnatal age of 3 days (0-87) were studied. There was a mean difference of 0.69 bpm (95% CI -2.9 to +1.5) between AD-HR and ECG-HR with good correlation between modalities (r=0.94, p<0.01). The median time to achieve AD-HR was 3 s (1-45). The mean difference between DD-HR and ECG-HR was 5.37 bpm (95% CI -12.8 to +2.1) with moderate correlation (r=0.37, p=0.04). The mean difference between PO-HR and ECG-HR was 0.49 bpm (95% CI -1.5 to +0.51) with good correlation (r=0.99, p<0.01). The variability between AD-HR and ECG-HR decreased with decreasing weight. CONCLUSIONS AD-HR correlates well with ECG-HR. Further research in the delivery room is recommended before using AD-HR in this area.
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Feasibility and utility of portable ultrasound during retrieval of sick term and late preterm infants. Acta Paediatr 2016; 105:e549-e554. [PMID: 27628296 DOI: 10.1111/apa.13589] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/21/2016] [Accepted: 09/12/2016] [Indexed: 12/01/2022]
Abstract
AIM To determine the role of clinician performed ultrasound (CPU) during the retrieval and transport of critically ill term and near term newborns. METHODS A neonatologist with portable ultrasound accompanied a sample of newborn retrievals to perform cardiac and cerebral ultrasound before and after transportation. RESULTS A total of fifty-five babies were studied. Median birthweight: 3350 g (2220-5030 g). CPU led to a change in the planned receiving hospital in ten babies. Eleven babies were suspected congenital heart disease (CHD) prior to retrieval: eight confirmed CHD by CPU and three normal structure. One transported to a children's hospital for cardiology review was confirmed as having normal structure; one to a perinatal hospital where normal structure was confirmed and one baby died at the referring hospital and postmortem confirmed normal structure. In five babies with clinical pulmonary hypertension, CPU revealed unsuspected CHD. The destination was changed to a paediatric cardiology centre, avoiding a second retrieval. Eleven babies had evidence of haemodynamic compromise allowing targeting of inotropes. CONCLUSION This is the first study of CPU during retrieval of high-risk infants. Ultrasound in retrieval is feasible, allows accurate triage of babies to cardiac centres and may allow more accurate targeting of fluid and inotrope support.
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The timing of umbilical cord clamping at birth: physiological considerations. Matern Health Neonatol Perinatol 2016; 2:4. [PMID: 27298730 PMCID: PMC4904360 DOI: 10.1186/s40748-016-0032-y] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 06/10/2016] [Indexed: 11/10/2022] Open
Abstract
While it is now recognized that umbilical cord clamping (UCC) at birth is not necessarily an innocuous act, there is still much confusion concerning the potential benefits and harms of this common procedure. It is most commonly assumed that delaying UCC will automatically result in a time-dependent net placental-to-infant blood transfusion, irrespective of the infant's physiological state. Whether or not this occurs, will likely depend on the infant's physiological state and not on the amount of time that has elapsed between birth and umbilical cord clamping (UCC). However, we believe that this is an overly simplistic view of what can occur during delayed UCC and ignores the benefits associated with maintaining the infant's venous return and cardiac output during transition. Recent experimental evidence and observations in humans have provided compelling evidence to demonstrate that time is not a major factor influencing placental-to-infant blood transfusion after birth. Indeed, there are many factors that influence blood flow in the umbilical vessels after birth, which depending on the dominating factors could potentially result in infant-to-placental blood transfusion. The most dominant factors that influence umbilical artery and venous blood flows after birth are lung aeration, spontaneous inspirations, crying and uterine contractions. It is still not entirely clear whether gravity differentially alters umbilical artery and venous flows, although the available data suggests that its influence, if present, is minimal. While there is much support for delaying UCC at birth, much of the debate has focused on a time-based approach, which we believe is misguided. While a time-based approach is much easier and convenient for the caregiver, ignoring the infant's physiology during delayed UCC can potentially be counter-productive for the infant.
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Lung ultrasound accurately detects pneumothorax in a preterm newborn lamb model. J Paediatr Child Health 2016; 52:643-8. [PMID: 27088264 DOI: 10.1111/jpc.13154] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 12/23/2015] [Indexed: 11/26/2022]
Abstract
AIM Pneumothorax is a common emergency affecting extremely preterm. In adult studies, lung ultrasound has performed better than chest x-ray in the diagnosis of pneumothorax. The purpose of this study was to determine the efficacy of lung ultrasound (LUS) examination to detect pneumothorax using a preterm animal model. METHODS This was a prospective, observational study using newborn Border-Leicester lambs at gestational age = 126 days (equivalent to gestational age = 26 weeks in humans) receiving mechanical ventilation from birth to 2 h of life. At the conclusion of the experiment, LUS was performed, the lambs were then euthanised and a post-mortem exam was immediately performed. We used previously published ultrasound techniques to identify pneumothorax. Test characteristics of LUS to detect pneumothorax were calculated, using the post-mortem exam as the 'gold standard' test. RESULTS Nine lambs (18 lungs) were examined. Four lambs had a unilateral pneumothorax, all of which were identified by LUS with no false positives. CONCLUSIONS This was the first study to use post-mortem findings to test the efficacy of LUS to detect pneumothorax in a newborn animal model. Lung ultrasound accurately detected pneumothorax, verified by post-mortem exam, in premature, newborn lambs.
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Oxygen saturation profile of term equivalent extreme preterm infants at discharge - comparison with healthy term counterparts. Acta Paediatr 2016; 105:e94-8. [PMID: 26859420 DOI: 10.1111/apa.13306] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 11/30/2015] [Accepted: 12/08/2015] [Indexed: 11/27/2022]
Abstract
AIM Compare the oxygen saturation profiles before discharge of neonates born extremely preterm (<28 weeks), now at term equivalent age, with healthy term neonates and assess the impact of feeding on this profile in each group. METHODS We prospectively evaluated and compared the oxygen saturation profile in 15 very low birthweight infants at term equivalent age, ready to be discharged home without any oxygen and 15 term newborns after 48 hours of life. We also evaluated and compared the saturations of these two groups during a one-hour period during and after feeding. RESULTS Term equivalent preterm and term infants spent median 3% and 0%, respectively, of the time below 90% in a 12-hour saturation-recording period. Term infants spent a median 0.26% and 0.65% of the time in <90% saturation during feed time and no feed time, respectively. In contrast, preterm infants spent significantly more time <90% saturation (3.47% and 3.5% during feed time and no feed time, respectively). CONCLUSION Term equivalent preterm infants spent significantly more time in a saturation range <90% compared to term infants. Feeding had little effect on saturation profile overall within each group.
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Abstract
BACKGROUND The safest ranges of oxygen saturation in preterm infants have been the subject of debate. METHODS In two trials, conducted in Australia and the United Kingdom, infants born before 28 weeks' gestation were randomly assigned to either a lower (85 to 89%) or a higher (91 to 95%) oxygen-saturation range. During enrollment, the oximeters were revised to correct a calibration-algorithm artifact. The primary outcome was death or disability at a corrected gestational age of 2 years; this outcome was evaluated among infants whose oxygen saturation was measured with any study oximeter in the Australian trial and those whose oxygen saturation was measured with a revised oximeter in the U.K. trial. RESULTS After 1135 infants in Australia and 973 infants in the United Kingdom had been enrolled in the trial, an interim analysis showed increased mortality at a corrected gestational age of 36 weeks, and enrollment was stopped. Death or disability in the Australian trial (with all oximeters included) occurred in 247 of 549 infants (45.0%) in the lower-target group versus 217 of 545 infants (39.8%) in the higher-target group (adjusted relative risk, 1.12; 95% confidence interval [CI], 0.98 to 1.27; P=0.10); death or disability in the U.K. trial (with only revised oximeters included) occurred in 185 of 366 infants (50.5%) in the lower-target group versus 164 of 357 infants (45.9%) in the higher-target group (adjusted relative risk, 1.10; 95% CI, 0.97 to 1.24; P=0.15). In post hoc combined, unadjusted analyses that included all oximeters, death or disability occurred in 492 of 1022 infants (48.1%) in the lower-target group versus 437 of 1013 infants (43.1%) in the higher-target group (relative risk, 1.11; 95% CI, 1.01 to 1.23; P=0.02), and death occurred in 222 of 1045 infants (21.2%) in the lower-target group versus 185 of 1045 infants (17.7%) in the higher-target group (relative risk, 1.20; 95% CI, 1.01 to 1.43; P=0.04). In the group in which revised oximeters were used, death or disability occurred in 287 of 580 infants (49.5%) in the lower-target group versus 248 of 563 infants (44.0%) in the higher-target group (relative risk, 1.12; 95% CI, 0.99 to 1.27; P=0.07), and death occurred in 144 of 587 infants (24.5%) versus 99 of 586 infants (16.9%) (relative risk, 1.45; 95% CI, 1.16 to 1.82; P=0.001). CONCLUSIONS Use of an oxygen-saturation target range of 85 to 89% versus 91 to 95% resulted in nonsignificantly higher rates of death or disability at 2 years in each trial but in significantly increased risks of this combined outcome and of death alone in post hoc combined analyses. (Funded by the Australian National Health and Medical Research Council and others; BOOST-II Current Controlled Trials number, ISRCTN00842661, and Australian New Zealand Clinical Trials Registry number, ACTRN12605000055606.).
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Point of care ultrasound in the NICU-training, accreditation and ownership. Eur J Pediatr 2016; 175:289-90. [PMID: 26304034 DOI: 10.1007/s00431-015-2624-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Accepted: 08/14/2015] [Indexed: 11/29/2022]
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Ventilation-induced lung injury is not exacerbated by growth restriction in preterm lambs. Am J Physiol Lung Cell Mol Physiol 2016; 310:L213-23. [DOI: 10.1152/ajplung.00328.2015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/23/2015] [Indexed: 11/22/2022] Open
Abstract
Intrauterine growth restriction (IUGR) and preterm birth are frequent comorbidities and, combined, increase the risk of adverse respiratory outcomes compared with that in appropriately grown (AG) infants. Potential underlying reasons for this increased respiratory morbidity in IUGR infants compared with AG infants include altered fetal lung development, fetal lung inflammation, increased respiratory requirements, and/or increased ventilation-induced lung injury. IUGR was surgically induced in preterm fetal sheep (0.7 gestation) by ligation of a single umbilical artery. Four weeks later, preterm lambs were euthanized at delivery or delivered and ventilated for 2 h before euthanasia. Ventilator requirements, lung inflammation, early markers of lung injury, and morphological changes in lung parenchymal and vascular structure and surfactant composition were analyzed. IUGR preterm lambs weighed 30% less than AG preterm lambs, with increased brain-to-body weight ratio, indicating brain sparing. IUGR did not induce lung inflammation or injury or alter lung parenchymal and vascular structure compared with AG fetuses. IUGR and AG lambs had similar oxygenation and respiratory requirements after birth and had significant, but similar, increases in proinflammatory cytokine expression, lung injury markers, gene expression, and surfactant phosphatidylcholine species compared with unventilated controls. IUGR does not induce pulmonary structural changes in our model. Furthermore, IUGR and AG preterm lambs have similar ventilator requirements in the immediate postnatal period. This study suggests that increased morbidity and mortality in IUGR infants is not due to altered lung tissue or vascular structure, or to an altered response to early ventilation.
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Neurodevelopmental Outcomes of Premature Infants Treated for Patent Ductus Arteriosus: A Population-Based Cohort Study. J Pediatr 2015; 167:1025-32.e3. [PMID: 26227439 DOI: 10.1016/j.jpeds.2015.06.054] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 06/01/2015] [Accepted: 06/25/2015] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To compare neurodevelopmental outcomes of extremely preterm infants diagnosed with patent ductus arteriosus (PDA) who were treated medically or surgically and those who were not diagnosed with PDA or who did not undergo treatment for PDA. STUDY DESIGN This retrospective population-based cohort study used data from a geographically defined area in New South Wales and the Australian Capital Territory served by a network of 10 neonatal intensive care units. Patients included all preterm infants born at <29 completed weeks of gestation between 1998 and 2004. Moderate/severe functional disability at 2-3 years corrected age was defined as developmental delay, cerebral palsy requiring aids, sensorineural or conductive deafness (requiring bilateral hearing aids or cochlear implant), or bilateral blindness (best visual acuity of <6/60). RESULTS Follow-up information at age 2-3 years was available for 1473 infants (74.8%). Compared with infants not diagnosed with a PDA or who did not receive PDA treatment for PDA, those with medically treated PDA (aOR, 1.622; 95% CI, 1.199-2.196) and those with surgically treated PDA (aOR, 2.001; 95% CI, 1.126-3.556) were at significantly greater risk for adverse neurodevelopmental outcomes at age 2-3 years. CONCLUSION Our results demonstrate that treatment for PDA may be associated with a greater risk of adverse neurodevelopmental outcome at age 2-3 years. This was particularly so among infants born at <25 weeks gestation. These results may support permissive tolerance of PDAs; however, reasons for this association remain to be elucidated through carefully designed prospective trials.
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Abstract
Immediate clamping and cutting of the umbilical cord at birth has been the accepted standard of care for decades. The physiologic rationale relating umbilical cord clamping (UCC) to the events of the circulatory transition is not considered in arbitrarily recommended cord clamping times. Systematic review of early versus deferred UCC shows significant hemodynamic benefits to the deferred group. Mechanisms for this protective effect are considered in this review. The original concept of a placental transfusion with a volume load and prevention of low cardiac output relies on the physiological end point of the amount of blood transfused. The newer concept of an ordered physiological transition is increasingly supported. This model places aeration of the lungs and an increase in pulmonary blood flow back at the centre of the circulatory transition with timing of UCC being related to establishment of respiration. The need for "physiologically based" UCC is discussed.
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Prolonged rupture of membranes and pulmonary hypoplasia in very preterm infants: pathophysiology and guided treatment. J Pediatr 2015; 166:1113-20. [PMID: 25681201 DOI: 10.1016/j.jpeds.2015.01.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 11/19/2014] [Accepted: 01/06/2015] [Indexed: 11/30/2022]
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Protective ventilation of preterm lambs exposed to acute chorioamnionitis does not reduce ventilation-induced lung or brain injury. PLoS One 2014; 9:e112402. [PMID: 25379714 PMCID: PMC4224447 DOI: 10.1371/journal.pone.0112402] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 10/15/2014] [Indexed: 01/25/2023] Open
Abstract
Background The onset of mechanical ventilation is a critical time for the initiation of cerebral white matter (WM) injury in preterm neonates, particularly if they are inadvertently exposed to high tidal volumes (VT) in the delivery room. Protective ventilation strategies at birth reduce ventilation-induced lung and brain inflammation and injury, however its efficacy in a compromised newborn is not known. Chorioamnionitis is a common antecedent of preterm birth, and increases the risk and severity of WM injury. We investigated the effects of high VT ventilation, after chorioamnionitis, on preterm lung and WM inflammation and injury, and whether a protective ventilation strategy could mitigate the response. Methods Pregnant ewes (n = 18) received intra-amniotic lipopolysaccharide (LPS) 2 days before delivery, instrumentation and ventilation at 127±1 days gestation. Lambs were either immediately euthanased and used as unventilated controls (LPSUVC; n = 6), or were ventilated using an injurious high VT strategy (LPSINJ; n = 5) or a protective ventilation strategy (LPSPROT; n = 7) for a total of 90 min. Mean arterial pressure, heart rate and cerebral haemodynamics and oxygenation were measured continuously. Lungs and brains underwent molecular and histological assessment of inflammation and injury. Results LPSINJ lambs had poorer oxygenation than LPSPROT lambs. Ventilation requirements and cardiopulmonary and systemic haemodynamics were not different between ventilation strategies. Compared to unventilated lambs, LPSINJ and LPSPROT lambs had increases in pro-inflammatory cytokine expression within the lungs and brain, and increased astrogliosis (p<0.02) and cell death (p<0.05) in the WM, which were equivalent in magnitude between groups. Conclusions Ventilation after acute chorioamnionitis, irrespective of strategy used, increases haemodynamic instability and lung and cerebral inflammation and injury. Mechanical ventilation is a potential contributor to WM injury in infants exposed to chorioamnionitis.
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Post-implementation review of pulse oximetry screening of well newborns in an Australian tertiary maternity hospital. J Paediatr Child Health 2014; 50:920-5. [PMID: 24923996 DOI: 10.1111/jpc.12651] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/09/2014] [Indexed: 12/21/2022]
Abstract
AIM Despite there being evidence that pulse oximetry screening is better than clinical examination alone in early detection of CHD, implementation has been slow. The aim of this paper was to evaluate the practice after its implementation into routine care at Royal Prince Alfred Hospital in 2008. METHODS A single pulse oximetry measurement was incorporated in the routine discharge newborn examination or, with early discharge, as a part of the Midwife Discharge Support Programme. An oxygen saturation level greater than or equal to 95% was considered normal, and a level less than 95%, confirmed on a repeat measure, triggered a review and examination by a consultant neonatal paediatrician. The saturation levels were recorded in the hospital database. Ascertainment of major CHD requiring surgery in the first 12 months was performed by searching the cardiac surgery database of the Heart Centre for Children. RESULTS A total of 18 801 babies were screened over a 42-month period. Of these, four babies with major CHD were diagnosed prior to discharge with the main clinical alert resulting from routine pulse oximetry screening (true positive). Of the 11 cases with saturation <95% but no CHD (false positive cases), six had respiratory pathology. One baby with normal saturation level needed surgery in the first year for a large ventricular septal defect (false negative). The false positive rate of pulse oximetry screening for CHD was 0.13% with sensitivity 80%, specificity of 99.8%, a positive predictive value of 13.3% and a negative predictive value of 99.9%. Nine additional echocardiogram were required over 42 months. CONCLUSIONS These post-implementation data confirm that pulse oximetry screening increases early diagnosis of major CHD as well as other important pathology with a very low false positive rate and minimal requirement for extra echocardiograms. Pulse oximetry screening of apparently well newborns should become a standard of care.
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Abstract
Clinician performed ultrasound (CPU) by the clinician caring for a sick patient is increasingly used in critical care specialties. The real-time haemodynamic information obtained helps the clinician to understand underlying physiology, target treatment and refine clinical decision-making. Neonatologists are increasingly using ultrasound to assess sick neonates with a range of clinical presentations and demand for training and accreditation programmes is increasing. This review discusses the current expanded uses for CPU in the haemodynamic assessment of the sick neonate.
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MESH Headings
- Heart Defects, Congenital/diagnostic imaging
- Hemodynamics/physiology
- Humans
- Infant, Extremely Low Birth Weight
- Infant, Newborn
- Infant, Newborn, Diseases/diagnostic imaging
- Infant, Newborn, Diseases/physiopathology
- Infant, Premature
- Infant, Premature, Diseases/diagnostic imaging
- Oxygen Inhalation Therapy
- Persistent Fetal Circulation Syndrome/diagnostic imaging
- Ultrasonography
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Respiratory support for premature neonates in the delivery room: effects on cardiovascular function and the development of brain injury. Pediatr Res 2014; 75:682-8. [PMID: 24614803 DOI: 10.1038/pr.2014.40] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 12/16/2013] [Indexed: 02/02/2023]
Abstract
The transition to newborn life in preterm infants is complicated by immature cardiovascular and respiratory systems. Consequently, preterm infants often require respiratory support immediately after birth. Although aeration of the lung underpins the circulatory transition at birth, positive pressure ventilation can adversely affect cardiorespiratory function during this vulnerable period, reducing pulmonary blood flow and left ventricular output. Furthermore, pulmonary volutrauma is known to initiate pulmonary inflammatory responses, resulting in remote systemic involvement. This review focuses on the downstream consequences of positive pressure ventilation, in particular, interactions between cardiovascular output and the initiation of a systemic inflammatory cascade, on the immature brain. Recent studies have highlighted that positive pressure ventilation strategies are precursors of cerebral injury, probably mediated through cerebral blood flow instability. The presence of, or initiation of, an inflammatory cascade accentuates adverse cerebral blood flow, in addition to being a direct source of brain injury. Importantly, the degree of brain injury is dependent on the nature of the initial ventilation strategy used.
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Abstract
OBJECTIVE Failure of closure of the patent ductus arteriosus (PDA) may be associated with harm. Early cardiac ultrasound-targeted treatment of a large PDA may result in a reduction in adverse outcomes and need for later PDA closure with no increase in adverse effects. STUDY DESIGN Multicentre, double-blind, placebo-controlled randomised trial. SETTING Three neonatal intensive care units in Australia. PATIENTS AND INTERVENTIONS Eligible infants born <29 weeks were screened for a large PDA and received indomethacin or placebo before age 12 h. MAIN OUTCOME Death or abnormal cranial ultrasound. RESULTS The trial ceased enrolment early due to lack of availability of indomethacin. 164 eligible infants were screened before 12 h; of the 92 infants with a large PDA, 44 were randomised to indomethacin and 48 to placebo. There was no difference in the main outcome between groups. Infants receiving early indomethacin had significantly less early pulmonary haemorrhage (PH) (2% vs 21%), a trend towards less periventricular/intraventricular haemorrhage (PIVH) (4.5% vs 12.5%) and were less likely to receive later open-label treatment for a PDA (20% vs 40%). The 72 non-randomised infants with a small PDA were at low risk of pulmonary haemorrhage and had an 80% spontaneous PDA closure rate. CONCLUSIONS Early cardiac ultrasound-targeted treatment of a large PDA is feasible and safe, resulted in a reduction in early pulmonary haemorrhage and later medical treatment but had no effect on the primary outcome of death or abnormal cranial ultrasound. REGISTERED TRIAL Australian New Zealand Clinical Trials Registry (ACTRN12608000295347).
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Delaying cord clamping until ventilation onset improves cardiovascular function at birth in preterm lambs. J Physiol 2013; 591:2113-26. [PMID: 23401615 DOI: 10.1113/jphysiol.2012.250084] [Citation(s) in RCA: 295] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Delayed cord clamping improves circulatory stability in preterm infants at birth, but the underlying physiology is unclear. We investigated the effects of umbilical cord clamping, before and after ventilation onset, on cardiovascular function at birth. Prenatal surgery was performed on lambs (123 days) to implant catheters into the pulmonary and carotid arteries and probes to measure pulmonary (PBF), carotid (CaBF) and ductus arteriosus blood flows. Lambs were delivered at 126 ± 1 days and: (1) the umbilical cord was clamped at delivery and ventilation was delayed for about 2 min (Clamp 1st; n = 6), and (2) umbilical cord clamping was delayed for 3-4 min, until after ventilation was established (Vent 1st; n = 6). All lambs were subsequently ventilated for 30 min. In Clamp 1st lambs, cord clamping rapidly (within four heartbeats), but transiently, increased pulmonary and carotid arterial pressures (by ∼30%) and CaBF (from 30.2 ± 5.6 to 40.1 ± 4.6 ml min(-1) kg(-1)), which then decreased again within 30-60 s. Following ventilation onset, these parameters rapidly increased again. In Clamp 1st lambs, cord clamping reduced heart rate (by ∼40%) and right ventricular output (RVO; from 114.6 ± 14.4 to 38.8 ± 9.7 ml min(-1) kg(-1)), which were restored by ventilation. In Vent 1st lambs, cord clamping reduced RVO from 153.5 ± 3.8 to 119.2 ± 10.6 ml min(-1) kg(-1), did not affect heart rates and resulted in stable blood flows and pressures during transition. Delaying cord clamping for 3-4 min until after ventilation is established improves cardiovascular function by increasing pulmonary blood flow before the cord is clamped. As a result, cardiac output remains stable, leading to a smoother cardiovascular transition throughout the early newborn period.
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