A physiological approach to the timing of umbilical cord clamping at birth.
نویسندگان
چکیده
Umbilical cord clamping at birth has a major impact on an infant's cardiovascular system that varies in significance depending upon whether the infant has commenced breathing. As umbilical venous return is a major source of preload for the left ventricle during fetal life, recent experimental evidence has shown that clamping the umbilical cord severely limits cardiac venous return in the absence of pulmonary ventilation. As a result, cardiac output greatly reduces and remains low until breathing commences. Once the infant begins breathing, aeration of the lung triggers a large increase in pulmonary blood flow, which replaces umbilical venous return as the source of preload for the left ventricle. As a result, cardiac output markedly increases, as indicated by an increase in heart rate immediately after birth. Thus, infants born apnoeic and hypoxic and have their cords immediately clamped, are likely to have a restricted cardiac output combined with hypoxia. As increased cardiac output is a major physiological defence mechanism that counteracts the effects of hypoxaemia, limiting the increase in cardiac output exposes the infant to ischaemia along with hypoxia. However, if the infant commences breathing, aerates its lungs and increases pulmonary blood flow before the umbilical cord is clamped, then pulmonary venous return can immediately take over the supply of left ventricular preload upon cord clamping. As a result, there is no intervening period of reduced preload and cardiac output and the large swings in arterial pressures and flows are reduced leading to a more stable circulatory transition.
منابع مشابه
Umbilical Cord Clamping Timing in Preterm Infants Delivered by Cesarean Section
Background: The timing of umbilical cord clamping may affect the need to bloodtransfusion and other morbidities of preterm infants. This study aimed to compare three different cord clamping timing (immediate cord clamping, delayed cord clamping and umbilical cord milking) in preterm infants delivered by cesarean section (CS). <em...
متن کاملKnowledge and Practice of Umbilical Cord Clamping among Maternity Care Providers
Background & aim: Based on the current scientific evidence, delayed cord clamping (DCC) elevates early hemoglobin concentrations and iron stores in the neonate. However, the persistent practice of early cord clamping (ECC) is still a routine care. The aim of the present study was to investigate the umbilical cord clamping practices of maternity care providers in Oman. Methods: This cross-sectio...
متن کاملIs "Delayed Umbilical Cord Clamping" Beneficial for Premature Newborns?
Background: The appropriate moment for clamping the umbilical cord is controversial. Immediate cord clamping (ICC) is an item of active management of the third stage of labor (AMTSL). Unclamped umbilical cord may cause inconvenience in preterm neonates because they commonly need some levels of emergent services. Some studies revealed delayed cord clamping (DCC) of preterm neonates results in be...
متن کاملMankind’s first natural stem cell transplant
The timing of the umbilical cord clamping at birth is still controversial. In the modern era of medicine, the cord has been clamped early to facilitate resuscitation and stabilization of infants. However, recently delayed cord clamping has been supported by physicians because it allows for the physiological transfer of blood from the placenta to the infant. Many clinical studies have revealed t...
متن کاملThe timing of umbilical cord clamping at birth: physiological considerations
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. Whet...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Archives of disease in childhood. Fetal and neonatal edition
دوره 100 4 شماره
صفحات -
تاریخ انتشار 2015