Physiological measurements of the effect of cord clamping strategies

Abstract

In this thesis we have investigated spontaneous breathing as a possible driving force for placental transfusion and the implementation of PBCC in a clinical setting. Spontaneous breathing at birth, and lung aeration, is pivotal to accomplish the increase in pulmonary blood flow and decrease in pulmonary vascular resistance needed for a successful transition to extra-uterine life. Indeed, we demonstrated spontaneous breathing to influence umbilical blood flow and to potentially create a preferential blood flow from the placenta towards the infant. Based on this thesis we have therefore concluded that spontaneous breathing is likely to be a driving force in placental transfusion. In addition, we investigated physiological-based cord clamping (PBCC). Experimental studies clearly demonstrated the beneficial physiological effects of PBCC and that lung aeration, with the subsequent increase in pulmonary blood flow, is vital for the success of this approach. The studies in this thesis demonstrate the proof of concept for performing PBCC in preterm infants in a clinical setting: that it is both possible and safe, and that a similar effect can be observed as in an experimental setting. We also demonstrated that resuscitation on the cord is at least as effective, while allowing longer and variable cord clamping times.