Low systemic blood flow occurs in up to 30% of infants born at less than 30 wk gestation. It is associated with increased morbidity and mortality, and current treatments are ineffective in 40% of cases. The aim of this study was to assess the ability of the preterm heart to respond to the acute shifts in preload and afterload that occur at the time of birth. Myocardial and coronary vascular function was assessed using an isolated working heart model in term (115 days) and preterm (92 days) piglets. Cardiac output/kg body wt in preterm hearts was ∼50% lower than that of term hearts (P = 0.001). Pressure development was similar in term and preterm hearts. Elevations in preload increased cardiac output and aortic flow similarly in term and preterm hearts, demonstrating significant preload "reserve". By contrast, elevations in afterload markedly depressed aortic flow, with a greater proportion of cardiac output being distributed to coronary flow in preterm hearts at high afterloads. The demands of increased workload were associated with greater increases in coronary flow in preterm hearts compared with term hearts. In preterm hearts, exposure to maternal glucocorticoids resulted in increased aortic flow when afterload was below 25 mmHg. These data suggest the preterm heart lacks the functional capacity to acutely adapt to postnatal afterload. To maximize systemic blood flow in preterm infants, treatments limiting afterload, while harnessing significant preload reserve, should be further explored.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1152/ajpregu.00010.2012 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Nocturnal pulse oxygen saturation dynamics at simulated high altitude: Predictive value for acute mountain sickness in healthy men born pre-term.
Exp Physiol
January 2025
Department for Automatics, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia.
The physiological sequelae of pre-term birth might influence the responses of this population to hypoxia. Moreover, identifying variables associated with development of acute mountain sickness (AMS) remains a key practically significant area of altitude research. We investigated the effects of pre-term birth on nocturnal oxygen saturation ( ) dynamics and assessed the predictive potential of nocturnal -related metrics for morning AMS in 12 healthy adults with gestational age < 32 weeks (pre-term) and 12 term-born control participants.
View Article and Find Full Text PDFHeart Rate Variability Does Not Predict Recurrence of Apnoea of Prematurity After Ceasing Caffeine Therapy: A Prospective Cohort Study.
Acta Paediatr
January 2025
Department of Neonatology, University Children's Hospital Basel UKBB, University of Basel, Basel, Switzerland.
Aim: We evaluated whether sample entropy of heart rate time series could serve as a biomarker for guiding caffeine cessation in preterm infants treated for apnoea of prematurity (AOP). We also assessed associations of sample entropy with weeks of gestation, clinical morbidity, AOP frequency and caffeine reinitiation.
Methods: We conducted a prospective single-centre study at the University Children's Hospital Basel, Switzerland, from July 2019 to June 2020.
Background: Pregnant patients with cardiovascular disease (CVD) face increased risk of preeclampsia and preterm delivery, yet data is limited data regarding degree of risk and impact of hypertensive disorders of pregnancy (HDP) on gestational age at delivery.
Objectives: To examine HDP risk and impact on delivery timing in patients with CVD.
Methods: This retrospective cohort study included patients >18 years old who delivered between 10/1/2015 and 12/31/2020 using the Premier Healthcare Database.
Antenatal betamethasone augments lung perfusion but lowers upper body blood flow and O delivery with delayed cord clamping at birth in preterm lambs.
J Physiol
January 2025
Heart Research, Murdoch Children's Research Institute, Parkville, Victoria, Australia.
Although the corticosteroid betamethasone is routinely administered to accelerate lung and cardiovascular maturation in the preterm fetus prior to birth, and use of delayed cord clamping (DCC) is recommended at birth by professional bodies, it is unknown whether antenatal betamethasone alters perinatal pulmonary or systemic arterial blood flow accompaniments of DCC. To address this issue, preterm fetal lambs [gestation 127 (1) days, term = 147 days] with (n = 10) or without (n = 10) antenatal betamethasone treatment were acutely instrumented under general anaesthesia with flow probes to obtain left (LV) and right ventricular (RV) outputs, major central arterial blood flows and shunt flow across both the ductus arteriosus and foramen ovale (FO). After delivery, lambs underwent initial ventilation for 2 min prior to DCC.
View Article and Find Full Text PDFThe development of preterm infants from low socio-economic status families: The combined effects of melatonin, autonomic nervous system maturation and psychosocial factors (ProMote): A study protocol.
PLoS One
January 2025
Department of Neonatology/Neonatal Intensive Care Unit, University Hospital of Heraklion, School of Medicine, University of Crete, Heraklion, Crete, Greece.
Preterm births constitute a major public health issue and a chronic, cross-generational condition globally. Psychological and biological factors interact in a way that women from low socio-economic status (SES) are disproportionally affected by preterm delivery and at increased risk for the development of perinatal mental health problems. Low SES constitutes one of the most evident contributors to poor neurodevelopment of preterm infants.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!