Physiological-based cord clamping in very preterm infants: the Aeration, Breathing, Clamping 3 (ABC3) trial—study protocol for a multicentre randomised controlled trial

Abstract

Background International guidelines recommend delayed umbilical cord clamping (DCC) up to 1 min in preterm infants, unless the condition of the infant requires immediate resuscitation. However, clamping the cord prior to lung aeration may severely limit circulatory adaptation resulting in a reduction in cardiac output and hypoxia. Delaying cord clamping until lung aeration and ventilation have been established (physiological-based cord clamping, PBCC) allows for an adequately established pulmonary circulation and results in a more stable circulatory transition. The decline in cardiac output following time-based delayed cord clamping (TBCC) may thus be avoided. We hypothesise that PBCC, compared to TBCC, results in a more stable transition in very preterm infants, leading to improved clinical outcomes. The primary objective is to compare the effect of PBCC on intact survival with TBCC. Methods The Aeriation, Breathing, Clamping 3 (ABC3) trial is a multicentre randomised controlled clinical trial. In the interventional PBCC group, the umbilical cord is clamped after the infant is stabilised, defined as reaching heart rate > 100 bpm and SpO2 > 85% while using supplemental oxygen < 40%. In the control TBCC group, cord clamping is time based at 30–60 s. The primary outcome is survival without major cerebral and/or intestinal injury. Preterm infants born before 30 weeks of gestation are included after prenatal parental informed consent. The required sample size is 660 infants. Discussion The findings of this trial will provide evidence for future clinical guidelines on optimal cord clamping management in very preterm infants at birth. Trial registration ClinicalTrials.gov NCT03808051. First registered on January 17, 2019.

Ventilatory Assistance Before Umbilical Cord Clamping in Extremely Preterm Infants

“…An additional limitation is that we could not assess lung aeration prior to cord clamping. In another trial of physiologic-based cord clamping, respiratory and vital sign monitoring during the intervention were used to determine when to cut the cord …”

“…In another trial of physiologic-based cord clamping, respiratory and vital sign monitoring during the intervention were used to determine when to cut the cord. 21 …”

Thermoregulation for very preterm infants in the delivery room: a narrative review

“…A number of mobile resuscitation trolleys (MRT) have been manufactured and studies of feasibility and efficacy are ongoing. 97 , 101 The thermal care afforded by commercially available MRTs varies from none, to a heated mattress (e.g., LifeStart TM ) or an overhead radiant heater (e.g., Concord™). In a study comparing ICC (<20 s) or placement on an MRT with CC at 2 min there was no difference in the incidence of admission hypothermia between the two groups (13% vs 14%), 102 however the authors did not describe the thermal care provided for either group.…”

Placental Perfusion Rather Than Placental Transfusion—Key to Umbilical Cord Management at Birth?

“…Results from additional studies of PBCC, using resuscitation with cord and placenta still intact with the uterus, will soon be available . These studies will be important, in particular given that they also include infants delivered by vaginal birth, a group that cannot receive EPP.…”

“…Results from additional studies of PBCC, using resuscitation with cord and placenta still intact with the uterus, will soon be available. 5 These studies will be important, in particular given that they also include infants delivered by vaginal birth, a group that cannot receive EPP. We do not have a direct comparison of EPP vs PBCC in which the placenta remains in situ, and studies assessing this question would be valuable.…”